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6238 lines
194 KiB
C
6238 lines
194 KiB
C
/* Fold a constant sub-tree into a single node for C-compiler
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Copyright (C) 1987, 88, 92-98, 1999 Free Software Foundation, Inc.
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This file is part of GNU CC.
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GNU CC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU CC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/*@@ This file should be rewritten to use an arbitrary precision
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@@ representation for "struct tree_int_cst" and "struct tree_real_cst".
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@@ Perhaps the routines could also be used for bc/dc, and made a lib.
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@@ The routines that translate from the ap rep should
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@@ warn if precision et. al. is lost.
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@@ This would also make life easier when this technology is used
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@@ for cross-compilers. */
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/* The entry points in this file are fold, size_int_wide, size_binop
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and force_fit_type.
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fold takes a tree as argument and returns a simplified tree.
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size_binop takes a tree code for an arithmetic operation
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and two operands that are trees, and produces a tree for the
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result, assuming the type comes from `sizetype'.
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size_int takes an integer value, and creates a tree constant
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with type from `sizetype'.
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force_fit_type takes a constant and prior overflow indicator, and
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forces the value to fit the type. It returns an overflow indicator. */
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#include "config.h"
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#include "system.h"
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#include <setjmp.h>
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#include "flags.h"
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#include "tree.h"
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#include "toplev.h"
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/* Handle floating overflow for `const_binop'. */
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static jmp_buf float_error;
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static void encode PROTO((HOST_WIDE_INT *,
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HOST_WIDE_INT, HOST_WIDE_INT));
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static void decode PROTO((HOST_WIDE_INT *,
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HOST_WIDE_INT *, HOST_WIDE_INT *));
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int div_and_round_double PROTO((enum tree_code, int, HOST_WIDE_INT,
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HOST_WIDE_INT, HOST_WIDE_INT,
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HOST_WIDE_INT, HOST_WIDE_INT *,
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HOST_WIDE_INT *, HOST_WIDE_INT *,
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HOST_WIDE_INT *));
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static int split_tree PROTO((tree, enum tree_code, tree *,
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tree *, int *));
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static tree int_const_binop PROTO((enum tree_code, tree, tree, int, int));
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static tree const_binop PROTO((enum tree_code, tree, tree, int));
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static tree fold_convert PROTO((tree, tree));
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static enum tree_code invert_tree_comparison PROTO((enum tree_code));
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static enum tree_code swap_tree_comparison PROTO((enum tree_code));
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static int truth_value_p PROTO((enum tree_code));
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static int operand_equal_for_comparison_p PROTO((tree, tree, tree));
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static int twoval_comparison_p PROTO((tree, tree *, tree *, int *));
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static tree eval_subst PROTO((tree, tree, tree, tree, tree));
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static tree omit_one_operand PROTO((tree, tree, tree));
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static tree pedantic_omit_one_operand PROTO((tree, tree, tree));
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static tree distribute_bit_expr PROTO((enum tree_code, tree, tree, tree));
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static tree make_bit_field_ref PROTO((tree, tree, int, int, int));
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static tree optimize_bit_field_compare PROTO((enum tree_code, tree,
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tree, tree));
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static tree decode_field_reference PROTO((tree, int *, int *,
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enum machine_mode *, int *,
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int *, tree *, tree *));
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static int all_ones_mask_p PROTO((tree, int));
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static int simple_operand_p PROTO((tree));
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static tree range_binop PROTO((enum tree_code, tree, tree, int,
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tree, int));
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static tree make_range PROTO((tree, int *, tree *, tree *));
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static tree build_range_check PROTO((tree, tree, int, tree, tree));
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static int merge_ranges PROTO((int *, tree *, tree *, int, tree, tree,
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int, tree, tree));
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static tree fold_range_test PROTO((tree));
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static tree unextend PROTO((tree, int, int, tree));
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static tree fold_truthop PROTO((enum tree_code, tree, tree, tree));
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static tree strip_compound_expr PROTO((tree, tree));
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static int multiple_of_p PROTO((tree, tree, tree));
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static tree constant_boolean_node PROTO((int, tree));
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#ifndef BRANCH_COST
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#define BRANCH_COST 1
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#endif
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/* Suppose A1 + B1 = SUM1, using 2's complement arithmetic ignoring overflow.
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Suppose A, B and SUM have the same respective signs as A1, B1, and SUM1.
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Then this yields nonzero if overflow occurred during the addition.
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Overflow occurs if A and B have the same sign, but A and SUM differ in sign.
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Use `^' to test whether signs differ, and `< 0' to isolate the sign. */
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#define overflow_sum_sign(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
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/* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
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We do that by representing the two-word integer in 4 words, with only
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HOST_BITS_PER_WIDE_INT/2 bits stored in each word, as a positive number. */
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#define LOWPART(x) \
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((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT/2)) - 1))
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#define HIGHPART(x) \
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((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT/2)
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#define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT/2)
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/* Unpack a two-word integer into 4 words.
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LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
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WORDS points to the array of HOST_WIDE_INTs. */
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static void
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encode (words, low, hi)
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HOST_WIDE_INT *words;
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HOST_WIDE_INT low, hi;
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{
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words[0] = LOWPART (low);
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words[1] = HIGHPART (low);
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words[2] = LOWPART (hi);
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words[3] = HIGHPART (hi);
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}
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/* Pack an array of 4 words into a two-word integer.
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WORDS points to the array of words.
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The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
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static void
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decode (words, low, hi)
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HOST_WIDE_INT *words;
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HOST_WIDE_INT *low, *hi;
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{
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*low = words[0] | words[1] * BASE;
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*hi = words[2] | words[3] * BASE;
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}
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/* Make the integer constant T valid for its type
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by setting to 0 or 1 all the bits in the constant
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that don't belong in the type.
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Yield 1 if a signed overflow occurs, 0 otherwise.
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If OVERFLOW is nonzero, a signed overflow has already occurred
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in calculating T, so propagate it.
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Make the real constant T valid for its type by calling CHECK_FLOAT_VALUE,
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if it exists. */
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int
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force_fit_type (t, overflow)
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tree t;
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int overflow;
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{
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HOST_WIDE_INT low, high;
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register int prec;
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if (TREE_CODE (t) == REAL_CST)
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{
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#ifdef CHECK_FLOAT_VALUE
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CHECK_FLOAT_VALUE (TYPE_MODE (TREE_TYPE (t)), TREE_REAL_CST (t),
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overflow);
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#endif
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return overflow;
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}
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else if (TREE_CODE (t) != INTEGER_CST)
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return overflow;
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low = TREE_INT_CST_LOW (t);
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high = TREE_INT_CST_HIGH (t);
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if (POINTER_TYPE_P (TREE_TYPE (t)))
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prec = POINTER_SIZE;
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else
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prec = TYPE_PRECISION (TREE_TYPE (t));
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/* First clear all bits that are beyond the type's precision. */
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if (prec == 2 * HOST_BITS_PER_WIDE_INT)
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;
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else if (prec > HOST_BITS_PER_WIDE_INT)
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{
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TREE_INT_CST_HIGH (t)
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&= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
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}
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else
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{
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TREE_INT_CST_HIGH (t) = 0;
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if (prec < HOST_BITS_PER_WIDE_INT)
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TREE_INT_CST_LOW (t) &= ~((HOST_WIDE_INT) (-1) << prec);
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}
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/* Unsigned types do not suffer sign extension or overflow. */
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if (TREE_UNSIGNED (TREE_TYPE (t)))
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return overflow;
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/* If the value's sign bit is set, extend the sign. */
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if (prec != 2 * HOST_BITS_PER_WIDE_INT
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&& (prec > HOST_BITS_PER_WIDE_INT
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? (TREE_INT_CST_HIGH (t)
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& ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1)))
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: TREE_INT_CST_LOW (t) & ((HOST_WIDE_INT) 1 << (prec - 1))))
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{
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/* Value is negative:
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set to 1 all the bits that are outside this type's precision. */
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if (prec > HOST_BITS_PER_WIDE_INT)
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{
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TREE_INT_CST_HIGH (t)
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|= ((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
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}
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else
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{
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TREE_INT_CST_HIGH (t) = -1;
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if (prec < HOST_BITS_PER_WIDE_INT)
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TREE_INT_CST_LOW (t) |= ((HOST_WIDE_INT) (-1) << prec);
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}
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}
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/* Yield nonzero if signed overflow occurred. */
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return
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((overflow | (low ^ TREE_INT_CST_LOW (t)) | (high ^ TREE_INT_CST_HIGH (t)))
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!= 0);
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}
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/* Add two doubleword integers with doubleword result.
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Each argument is given as two `HOST_WIDE_INT' pieces.
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One argument is L1 and H1; the other, L2 and H2.
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The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
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int
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add_double (l1, h1, l2, h2, lv, hv)
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HOST_WIDE_INT l1, h1, l2, h2;
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HOST_WIDE_INT *lv, *hv;
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{
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HOST_WIDE_INT l, h;
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l = l1 + l2;
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h = h1 + h2 + ((unsigned HOST_WIDE_INT) l < l1);
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*lv = l;
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*hv = h;
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return overflow_sum_sign (h1, h2, h);
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}
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/* Negate a doubleword integer with doubleword result.
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Return nonzero if the operation overflows, assuming it's signed.
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The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
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The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
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int
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neg_double (l1, h1, lv, hv)
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HOST_WIDE_INT l1, h1;
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HOST_WIDE_INT *lv, *hv;
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{
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if (l1 == 0)
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{
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*lv = 0;
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*hv = - h1;
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return (*hv & h1) < 0;
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}
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else
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{
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*lv = - l1;
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*hv = ~ h1;
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return 0;
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}
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}
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/* Multiply two doubleword integers with doubleword result.
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Return nonzero if the operation overflows, assuming it's signed.
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Each argument is given as two `HOST_WIDE_INT' pieces.
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One argument is L1 and H1; the other, L2 and H2.
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The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
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int
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mul_double (l1, h1, l2, h2, lv, hv)
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HOST_WIDE_INT l1, h1, l2, h2;
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HOST_WIDE_INT *lv, *hv;
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{
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HOST_WIDE_INT arg1[4];
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HOST_WIDE_INT arg2[4];
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HOST_WIDE_INT prod[4 * 2];
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register unsigned HOST_WIDE_INT carry;
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register int i, j, k;
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HOST_WIDE_INT toplow, tophigh, neglow, neghigh;
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encode (arg1, l1, h1);
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encode (arg2, l2, h2);
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bzero ((char *) prod, sizeof prod);
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for (i = 0; i < 4; i++)
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{
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carry = 0;
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for (j = 0; j < 4; j++)
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{
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k = i + j;
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/* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
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carry += arg1[i] * arg2[j];
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/* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
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carry += prod[k];
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prod[k] = LOWPART (carry);
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carry = HIGHPART (carry);
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}
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prod[i + 4] = carry;
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}
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decode (prod, lv, hv); /* This ignores prod[4] through prod[4*2-1] */
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/* Check for overflow by calculating the top half of the answer in full;
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it should agree with the low half's sign bit. */
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decode (prod+4, &toplow, &tophigh);
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if (h1 < 0)
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{
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neg_double (l2, h2, &neglow, &neghigh);
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add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
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}
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if (h2 < 0)
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{
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neg_double (l1, h1, &neglow, &neghigh);
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add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
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}
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return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
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}
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/* Shift the doubleword integer in L1, H1 left by COUNT places
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keeping only PREC bits of result.
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Shift right if COUNT is negative.
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ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
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Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
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void
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lshift_double (l1, h1, count, prec, lv, hv, arith)
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HOST_WIDE_INT l1, h1, count;
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int prec;
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HOST_WIDE_INT *lv, *hv;
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int arith;
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{
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if (count < 0)
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{
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rshift_double (l1, h1, - count, prec, lv, hv, arith);
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return;
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}
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#ifdef SHIFT_COUNT_TRUNCATED
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if (SHIFT_COUNT_TRUNCATED)
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count %= prec;
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#endif
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if (count >= HOST_BITS_PER_WIDE_INT)
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{
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*hv = (unsigned HOST_WIDE_INT) l1 << (count - HOST_BITS_PER_WIDE_INT);
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*lv = 0;
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}
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else
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{
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*hv = (((unsigned HOST_WIDE_INT) h1 << count)
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| ((unsigned HOST_WIDE_INT) l1 >> (HOST_BITS_PER_WIDE_INT - count - 1) >> 1));
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*lv = (unsigned HOST_WIDE_INT) l1 << count;
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}
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}
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/* Shift the doubleword integer in L1, H1 right by COUNT places
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keeping only PREC bits of result. COUNT must be positive.
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ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
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Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
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|
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void
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rshift_double (l1, h1, count, prec, lv, hv, arith)
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HOST_WIDE_INT l1, h1, count;
|
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int prec;
|
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HOST_WIDE_INT *lv, *hv;
|
||
int arith;
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{
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unsigned HOST_WIDE_INT signmask;
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||
signmask = (arith
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? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1))
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: 0);
|
||
|
||
#ifdef SHIFT_COUNT_TRUNCATED
|
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if (SHIFT_COUNT_TRUNCATED)
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count %= prec;
|
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#endif
|
||
|
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if (count >= HOST_BITS_PER_WIDE_INT)
|
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{
|
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*hv = signmask;
|
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*lv = ((signmask << (2 * HOST_BITS_PER_WIDE_INT - count - 1) << 1)
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| ((unsigned HOST_WIDE_INT) h1 >> (count - HOST_BITS_PER_WIDE_INT)));
|
||
}
|
||
else
|
||
{
|
||
*lv = (((unsigned HOST_WIDE_INT) l1 >> count)
|
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| ((unsigned HOST_WIDE_INT) h1 << (HOST_BITS_PER_WIDE_INT - count - 1) << 1));
|
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*hv = ((signmask << (HOST_BITS_PER_WIDE_INT - count))
|
||
| ((unsigned HOST_WIDE_INT) h1 >> count));
|
||
}
|
||
}
|
||
|
||
/* Rotate the doubleword integer in L1, H1 left by COUNT places
|
||
keeping only PREC bits of result.
|
||
Rotate right if COUNT is negative.
|
||
Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
|
||
|
||
void
|
||
lrotate_double (l1, h1, count, prec, lv, hv)
|
||
HOST_WIDE_INT l1, h1, count;
|
||
int prec;
|
||
HOST_WIDE_INT *lv, *hv;
|
||
{
|
||
HOST_WIDE_INT s1l, s1h, s2l, s2h;
|
||
|
||
count %= prec;
|
||
if (count < 0)
|
||
count += prec;
|
||
|
||
lshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
|
||
rshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
|
||
*lv = s1l | s2l;
|
||
*hv = s1h | s2h;
|
||
}
|
||
|
||
/* Rotate the doubleword integer in L1, H1 left by COUNT places
|
||
keeping only PREC bits of result. COUNT must be positive.
|
||
Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
|
||
|
||
void
|
||
rrotate_double (l1, h1, count, prec, lv, hv)
|
||
HOST_WIDE_INT l1, h1, count;
|
||
int prec;
|
||
HOST_WIDE_INT *lv, *hv;
|
||
{
|
||
HOST_WIDE_INT s1l, s1h, s2l, s2h;
|
||
|
||
count %= prec;
|
||
if (count < 0)
|
||
count += prec;
|
||
|
||
rshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
|
||
lshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
|
||
*lv = s1l | s2l;
|
||
*hv = s1h | s2h;
|
||
}
|
||
|
||
/* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
|
||
for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
|
||
CODE is a tree code for a kind of division, one of
|
||
TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
|
||
or EXACT_DIV_EXPR
|
||
It controls how the quotient is rounded to a integer.
|
||
Return nonzero if the operation overflows.
|
||
UNS nonzero says do unsigned division. */
|
||
|
||
int
|
||
div_and_round_double (code, uns,
|
||
lnum_orig, hnum_orig, lden_orig, hden_orig,
|
||
lquo, hquo, lrem, hrem)
|
||
enum tree_code code;
|
||
int uns;
|
||
HOST_WIDE_INT lnum_orig, hnum_orig; /* num == numerator == dividend */
|
||
HOST_WIDE_INT lden_orig, hden_orig; /* den == denominator == divisor */
|
||
HOST_WIDE_INT *lquo, *hquo, *lrem, *hrem;
|
||
{
|
||
int quo_neg = 0;
|
||
HOST_WIDE_INT num[4 + 1]; /* extra element for scaling. */
|
||
HOST_WIDE_INT den[4], quo[4];
|
||
register int i, j;
|
||
unsigned HOST_WIDE_INT work;
|
||
register unsigned HOST_WIDE_INT carry = 0;
|
||
HOST_WIDE_INT lnum = lnum_orig;
|
||
HOST_WIDE_INT hnum = hnum_orig;
|
||
HOST_WIDE_INT lden = lden_orig;
|
||
HOST_WIDE_INT hden = hden_orig;
|
||
int overflow = 0;
|
||
|
||
if ((hden == 0) && (lden == 0))
|
||
overflow = 1, lden = 1;
|
||
|
||
/* calculate quotient sign and convert operands to unsigned. */
|
||
if (!uns)
|
||
{
|
||
if (hnum < 0)
|
||
{
|
||
quo_neg = ~ quo_neg;
|
||
/* (minimum integer) / (-1) is the only overflow case. */
|
||
if (neg_double (lnum, hnum, &lnum, &hnum) && (lden & hden) == -1)
|
||
overflow = 1;
|
||
}
|
||
if (hden < 0)
|
||
{
|
||
quo_neg = ~ quo_neg;
|
||
neg_double (lden, hden, &lden, &hden);
|
||
}
|
||
}
|
||
|
||
if (hnum == 0 && hden == 0)
|
||
{ /* single precision */
|
||
*hquo = *hrem = 0;
|
||
/* This unsigned division rounds toward zero. */
|
||
*lquo = lnum / (unsigned HOST_WIDE_INT) lden;
|
||
goto finish_up;
|
||
}
|
||
|
||
if (hnum == 0)
|
||
{ /* trivial case: dividend < divisor */
|
||
/* hden != 0 already checked. */
|
||
*hquo = *lquo = 0;
|
||
*hrem = hnum;
|
||
*lrem = lnum;
|
||
goto finish_up;
|
||
}
|
||
|
||
bzero ((char *) quo, sizeof quo);
|
||
|
||
bzero ((char *) num, sizeof num); /* to zero 9th element */
|
||
bzero ((char *) den, sizeof den);
|
||
|
||
encode (num, lnum, hnum);
|
||
encode (den, lden, hden);
|
||
|
||
/* Special code for when the divisor < BASE. */
|
||
if (hden == 0 && lden < BASE)
|
||
{
|
||
/* hnum != 0 already checked. */
|
||
for (i = 4 - 1; i >= 0; i--)
|
||
{
|
||
work = num[i] + carry * BASE;
|
||
quo[i] = work / (unsigned HOST_WIDE_INT) lden;
|
||
carry = work % (unsigned HOST_WIDE_INT) lden;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* Full double precision division,
|
||
with thanks to Don Knuth's "Seminumerical Algorithms". */
|
||
int num_hi_sig, den_hi_sig;
|
||
unsigned HOST_WIDE_INT quo_est, scale;
|
||
|
||
/* Find the highest non-zero divisor digit. */
|
||
for (i = 4 - 1; ; i--)
|
||
if (den[i] != 0) {
|
||
den_hi_sig = i;
|
||
break;
|
||
}
|
||
|
||
/* Insure that the first digit of the divisor is at least BASE/2.
|
||
This is required by the quotient digit estimation algorithm. */
|
||
|
||
scale = BASE / (den[den_hi_sig] + 1);
|
||
if (scale > 1) { /* scale divisor and dividend */
|
||
carry = 0;
|
||
for (i = 0; i <= 4 - 1; i++) {
|
||
work = (num[i] * scale) + carry;
|
||
num[i] = LOWPART (work);
|
||
carry = HIGHPART (work);
|
||
} num[4] = carry;
|
||
carry = 0;
|
||
for (i = 0; i <= 4 - 1; i++) {
|
||
work = (den[i] * scale) + carry;
|
||
den[i] = LOWPART (work);
|
||
carry = HIGHPART (work);
|
||
if (den[i] != 0) den_hi_sig = i;
|
||
}
|
||
}
|
||
|
||
num_hi_sig = 4;
|
||
|
||
/* Main loop */
|
||
for (i = num_hi_sig - den_hi_sig - 1; i >= 0; i--) {
|
||
/* guess the next quotient digit, quo_est, by dividing the first
|
||
two remaining dividend digits by the high order quotient digit.
|
||
quo_est is never low and is at most 2 high. */
|
||
unsigned HOST_WIDE_INT tmp;
|
||
|
||
num_hi_sig = i + den_hi_sig + 1;
|
||
work = num[num_hi_sig] * BASE + num[num_hi_sig - 1];
|
||
if (num[num_hi_sig] != den[den_hi_sig])
|
||
quo_est = work / den[den_hi_sig];
|
||
else
|
||
quo_est = BASE - 1;
|
||
|
||
/* refine quo_est so it's usually correct, and at most one high. */
|
||
tmp = work - quo_est * den[den_hi_sig];
|
||
if (tmp < BASE
|
||
&& den[den_hi_sig - 1] * quo_est > (tmp * BASE + num[num_hi_sig - 2]))
|
||
quo_est--;
|
||
|
||
/* Try QUO_EST as the quotient digit, by multiplying the
|
||
divisor by QUO_EST and subtracting from the remaining dividend.
|
||
Keep in mind that QUO_EST is the I - 1st digit. */
|
||
|
||
carry = 0;
|
||
for (j = 0; j <= den_hi_sig; j++)
|
||
{
|
||
work = quo_est * den[j] + carry;
|
||
carry = HIGHPART (work);
|
||
work = num[i + j] - LOWPART (work);
|
||
num[i + j] = LOWPART (work);
|
||
carry += HIGHPART (work) != 0;
|
||
}
|
||
|
||
/* if quo_est was high by one, then num[i] went negative and
|
||
we need to correct things. */
|
||
|
||
if (num[num_hi_sig] < carry)
|
||
{
|
||
quo_est--;
|
||
carry = 0; /* add divisor back in */
|
||
for (j = 0; j <= den_hi_sig; j++)
|
||
{
|
||
work = num[i + j] + den[j] + carry;
|
||
carry = HIGHPART (work);
|
||
num[i + j] = LOWPART (work);
|
||
}
|
||
num [num_hi_sig] += carry;
|
||
}
|
||
|
||
/* store the quotient digit. */
|
||
quo[i] = quo_est;
|
||
}
|
||
}
|
||
|
||
decode (quo, lquo, hquo);
|
||
|
||
finish_up:
|
||
/* if result is negative, make it so. */
|
||
if (quo_neg)
|
||
neg_double (*lquo, *hquo, lquo, hquo);
|
||
|
||
/* compute trial remainder: rem = num - (quo * den) */
|
||
mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
|
||
neg_double (*lrem, *hrem, lrem, hrem);
|
||
add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
|
||
|
||
switch (code)
|
||
{
|
||
case TRUNC_DIV_EXPR:
|
||
case TRUNC_MOD_EXPR: /* round toward zero */
|
||
case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */
|
||
return overflow;
|
||
|
||
case FLOOR_DIV_EXPR:
|
||
case FLOOR_MOD_EXPR: /* round toward negative infinity */
|
||
if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */
|
||
{
|
||
/* quo = quo - 1; */
|
||
add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1,
|
||
lquo, hquo);
|
||
}
|
||
else return overflow;
|
||
break;
|
||
|
||
case CEIL_DIV_EXPR:
|
||
case CEIL_MOD_EXPR: /* round toward positive infinity */
|
||
if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */
|
||
{
|
||
add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
|
||
lquo, hquo);
|
||
}
|
||
else return overflow;
|
||
break;
|
||
|
||
case ROUND_DIV_EXPR:
|
||
case ROUND_MOD_EXPR: /* round to closest integer */
|
||
{
|
||
HOST_WIDE_INT labs_rem = *lrem, habs_rem = *hrem;
|
||
HOST_WIDE_INT labs_den = lden, habs_den = hden, ltwice, htwice;
|
||
|
||
/* get absolute values */
|
||
if (*hrem < 0) neg_double (*lrem, *hrem, &labs_rem, &habs_rem);
|
||
if (hden < 0) neg_double (lden, hden, &labs_den, &habs_den);
|
||
|
||
/* if (2 * abs (lrem) >= abs (lden)) */
|
||
mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0,
|
||
labs_rem, habs_rem, <wice, &htwice);
|
||
if (((unsigned HOST_WIDE_INT) habs_den
|
||
< (unsigned HOST_WIDE_INT) htwice)
|
||
|| (((unsigned HOST_WIDE_INT) habs_den
|
||
== (unsigned HOST_WIDE_INT) htwice)
|
||
&& ((HOST_WIDE_INT unsigned) labs_den
|
||
< (unsigned HOST_WIDE_INT) ltwice)))
|
||
{
|
||
if (*hquo < 0)
|
||
/* quo = quo - 1; */
|
||
add_double (*lquo, *hquo,
|
||
(HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo);
|
||
else
|
||
/* quo = quo + 1; */
|
||
add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
|
||
lquo, hquo);
|
||
}
|
||
else return overflow;
|
||
}
|
||
break;
|
||
|
||
default:
|
||
abort ();
|
||
}
|
||
|
||
/* compute true remainder: rem = num - (quo * den) */
|
||
mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
|
||
neg_double (*lrem, *hrem, lrem, hrem);
|
||
add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
|
||
return overflow;
|
||
}
|
||
|
||
#ifndef REAL_ARITHMETIC
|
||
/* Effectively truncate a real value to represent the nearest possible value
|
||
in a narrower mode. The result is actually represented in the same data
|
||
type as the argument, but its value is usually different.
|
||
|
||
A trap may occur during the FP operations and it is the responsibility
|
||
of the calling function to have a handler established. */
|
||
|
||
REAL_VALUE_TYPE
|
||
real_value_truncate (mode, arg)
|
||
enum machine_mode mode;
|
||
REAL_VALUE_TYPE arg;
|
||
{
|
||
return REAL_VALUE_TRUNCATE (mode, arg);
|
||
}
|
||
|
||
#if TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
|
||
|
||
/* Check for infinity in an IEEE double precision number. */
|
||
|
||
int
|
||
target_isinf (x)
|
||
REAL_VALUE_TYPE x;
|
||
{
|
||
/* The IEEE 64-bit double format. */
|
||
union {
|
||
REAL_VALUE_TYPE d;
|
||
struct {
|
||
unsigned sign : 1;
|
||
unsigned exponent : 11;
|
||
unsigned mantissa1 : 20;
|
||
unsigned mantissa2;
|
||
} little_endian;
|
||
struct {
|
||
unsigned mantissa2;
|
||
unsigned mantissa1 : 20;
|
||
unsigned exponent : 11;
|
||
unsigned sign : 1;
|
||
} big_endian;
|
||
} u;
|
||
|
||
u.d = dconstm1;
|
||
if (u.big_endian.sign == 1)
|
||
{
|
||
u.d = x;
|
||
return (u.big_endian.exponent == 2047
|
||
&& u.big_endian.mantissa1 == 0
|
||
&& u.big_endian.mantissa2 == 0);
|
||
}
|
||
else
|
||
{
|
||
u.d = x;
|
||
return (u.little_endian.exponent == 2047
|
||
&& u.little_endian.mantissa1 == 0
|
||
&& u.little_endian.mantissa2 == 0);
|
||
}
|
||
}
|
||
|
||
/* Check whether an IEEE double precision number is a NaN. */
|
||
|
||
int
|
||
target_isnan (x)
|
||
REAL_VALUE_TYPE x;
|
||
{
|
||
/* The IEEE 64-bit double format. */
|
||
union {
|
||
REAL_VALUE_TYPE d;
|
||
struct {
|
||
unsigned sign : 1;
|
||
unsigned exponent : 11;
|
||
unsigned mantissa1 : 20;
|
||
unsigned mantissa2;
|
||
} little_endian;
|
||
struct {
|
||
unsigned mantissa2;
|
||
unsigned mantissa1 : 20;
|
||
unsigned exponent : 11;
|
||
unsigned sign : 1;
|
||
} big_endian;
|
||
} u;
|
||
|
||
u.d = dconstm1;
|
||
if (u.big_endian.sign == 1)
|
||
{
|
||
u.d = x;
|
||
return (u.big_endian.exponent == 2047
|
||
&& (u.big_endian.mantissa1 != 0
|
||
|| u.big_endian.mantissa2 != 0));
|
||
}
|
||
else
|
||
{
|
||
u.d = x;
|
||
return (u.little_endian.exponent == 2047
|
||
&& (u.little_endian.mantissa1 != 0
|
||
|| u.little_endian.mantissa2 != 0));
|
||
}
|
||
}
|
||
|
||
/* Check for a negative IEEE double precision number. */
|
||
|
||
int
|
||
target_negative (x)
|
||
REAL_VALUE_TYPE x;
|
||
{
|
||
/* The IEEE 64-bit double format. */
|
||
union {
|
||
REAL_VALUE_TYPE d;
|
||
struct {
|
||
unsigned sign : 1;
|
||
unsigned exponent : 11;
|
||
unsigned mantissa1 : 20;
|
||
unsigned mantissa2;
|
||
} little_endian;
|
||
struct {
|
||
unsigned mantissa2;
|
||
unsigned mantissa1 : 20;
|
||
unsigned exponent : 11;
|
||
unsigned sign : 1;
|
||
} big_endian;
|
||
} u;
|
||
|
||
u.d = dconstm1;
|
||
if (u.big_endian.sign == 1)
|
||
{
|
||
u.d = x;
|
||
return u.big_endian.sign;
|
||
}
|
||
else
|
||
{
|
||
u.d = x;
|
||
return u.little_endian.sign;
|
||
}
|
||
}
|
||
#else /* Target not IEEE */
|
||
|
||
/* Let's assume other float formats don't have infinity.
|
||
(This can be overridden by redefining REAL_VALUE_ISINF.) */
|
||
|
||
target_isinf (x)
|
||
REAL_VALUE_TYPE x;
|
||
{
|
||
return 0;
|
||
}
|
||
|
||
/* Let's assume other float formats don't have NaNs.
|
||
(This can be overridden by redefining REAL_VALUE_ISNAN.) */
|
||
|
||
target_isnan (x)
|
||
REAL_VALUE_TYPE x;
|
||
{
|
||
return 0;
|
||
}
|
||
|
||
/* Let's assume other float formats don't have minus zero.
|
||
(This can be overridden by redefining REAL_VALUE_NEGATIVE.) */
|
||
|
||
target_negative (x)
|
||
REAL_VALUE_TYPE x;
|
||
{
|
||
return x < 0;
|
||
}
|
||
#endif /* Target not IEEE */
|
||
|
||
/* Try to change R into its exact multiplicative inverse in machine mode
|
||
MODE. Return nonzero function value if successful. */
|
||
|
||
int
|
||
exact_real_inverse (mode, r)
|
||
enum machine_mode mode;
|
||
REAL_VALUE_TYPE *r;
|
||
{
|
||
union
|
||
{
|
||
double d;
|
||
unsigned short i[4];
|
||
}x, t, y;
|
||
int i;
|
||
|
||
/* Usually disable if bounds checks are not reliable. */
|
||
if ((HOST_FLOAT_FORMAT != TARGET_FLOAT_FORMAT) && !flag_pretend_float)
|
||
return 0;
|
||
|
||
/* Set array index to the less significant bits in the unions, depending
|
||
on the endian-ness of the host doubles.
|
||
Disable if insufficient information on the data structure. */
|
||
#if HOST_FLOAT_FORMAT == UNKNOWN_FLOAT_FORMAT
|
||
return 0;
|
||
#else
|
||
#if HOST_FLOAT_FORMAT == VAX_FLOAT_FORMAT
|
||
#define K 2
|
||
#else
|
||
#if HOST_FLOAT_FORMAT == IBM_FLOAT_FORMAT
|
||
#define K 2
|
||
#else
|
||
#define K (2 * HOST_FLOAT_WORDS_BIG_ENDIAN)
|
||
#endif
|
||
#endif
|
||
#endif
|
||
|
||
if (setjmp (float_error))
|
||
{
|
||
/* Don't do the optimization if there was an arithmetic error. */
|
||
fail:
|
||
set_float_handler (NULL_PTR);
|
||
return 0;
|
||
}
|
||
set_float_handler (float_error);
|
||
|
||
/* Domain check the argument. */
|
||
x.d = *r;
|
||
if (x.d == 0.0)
|
||
goto fail;
|
||
|
||
#ifdef REAL_INFINITY
|
||
if (REAL_VALUE_ISINF (x.d) || REAL_VALUE_ISNAN (x.d))
|
||
goto fail;
|
||
#endif
|
||
|
||
/* Compute the reciprocal and check for numerical exactness.
|
||
It is unnecessary to check all the significand bits to determine
|
||
whether X is a power of 2. If X is not, then it is impossible for
|
||
the bottom half significand of both X and 1/X to be all zero bits.
|
||
Hence we ignore the data structure of the top half and examine only
|
||
the low order bits of the two significands. */
|
||
t.d = 1.0 / x.d;
|
||
if (x.i[K] != 0 || x.i[K + 1] != 0 || t.i[K] != 0 || t.i[K + 1] != 0)
|
||
goto fail;
|
||
|
||
/* Truncate to the required mode and range-check the result. */
|
||
y.d = REAL_VALUE_TRUNCATE (mode, t.d);
|
||
#ifdef CHECK_FLOAT_VALUE
|
||
i = 0;
|
||
if (CHECK_FLOAT_VALUE (mode, y.d, i))
|
||
goto fail;
|
||
#endif
|
||
|
||
/* Fail if truncation changed the value. */
|
||
if (y.d != t.d || y.d == 0.0)
|
||
goto fail;
|
||
|
||
#ifdef REAL_INFINITY
|
||
if (REAL_VALUE_ISINF (y.d) || REAL_VALUE_ISNAN (y.d))
|
||
goto fail;
|
||
#endif
|
||
|
||
/* Output the reciprocal and return success flag. */
|
||
set_float_handler (NULL_PTR);
|
||
*r = y.d;
|
||
return 1;
|
||
}
|
||
#endif /* no REAL_ARITHMETIC */
|
||
|
||
/* Split a tree IN into a constant and a variable part
|
||
that could be combined with CODE to make IN.
|
||
CODE must be a commutative arithmetic operation.
|
||
Store the constant part into *CONP and the variable in &VARP.
|
||
Return 1 if this was done; zero means the tree IN did not decompose
|
||
this way.
|
||
|
||
If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR.
|
||
Therefore, we must tell the caller whether the variable part
|
||
was subtracted. We do this by storing 1 or -1 into *VARSIGNP.
|
||
The value stored is the coefficient for the variable term.
|
||
The constant term we return should always be added;
|
||
we negate it if necessary. */
|
||
|
||
static int
|
||
split_tree (in, code, varp, conp, varsignp)
|
||
tree in;
|
||
enum tree_code code;
|
||
tree *varp, *conp;
|
||
int *varsignp;
|
||
{
|
||
register tree outtype = TREE_TYPE (in);
|
||
*varp = 0;
|
||
*conp = 0;
|
||
|
||
/* Strip any conversions that don't change the machine mode. */
|
||
while ((TREE_CODE (in) == NOP_EXPR
|
||
|| TREE_CODE (in) == CONVERT_EXPR)
|
||
&& (TYPE_MODE (TREE_TYPE (in))
|
||
== TYPE_MODE (TREE_TYPE (TREE_OPERAND (in, 0)))))
|
||
in = TREE_OPERAND (in, 0);
|
||
|
||
if (TREE_CODE (in) == code
|
||
|| (! FLOAT_TYPE_P (TREE_TYPE (in))
|
||
/* We can associate addition and subtraction together
|
||
(even though the C standard doesn't say so)
|
||
for integers because the value is not affected.
|
||
For reals, the value might be affected, so we can't. */
|
||
&& ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR)
|
||
|| (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR))))
|
||
{
|
||
enum tree_code code = TREE_CODE (TREE_OPERAND (in, 0));
|
||
if (code == INTEGER_CST)
|
||
{
|
||
*conp = TREE_OPERAND (in, 0);
|
||
*varp = TREE_OPERAND (in, 1);
|
||
if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
|
||
&& TREE_TYPE (*varp) != outtype)
|
||
*varp = convert (outtype, *varp);
|
||
*varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
|
||
return 1;
|
||
}
|
||
if (TREE_CONSTANT (TREE_OPERAND (in, 1)))
|
||
{
|
||
*conp = TREE_OPERAND (in, 1);
|
||
*varp = TREE_OPERAND (in, 0);
|
||
*varsignp = 1;
|
||
if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
|
||
&& TREE_TYPE (*varp) != outtype)
|
||
*varp = convert (outtype, *varp);
|
||
if (TREE_CODE (in) == MINUS_EXPR)
|
||
{
|
||
/* If operation is subtraction and constant is second,
|
||
must negate it to get an additive constant.
|
||
And this cannot be done unless it is a manifest constant.
|
||
It could also be the address of a static variable.
|
||
We cannot negate that, so give up. */
|
||
if (TREE_CODE (*conp) == INTEGER_CST)
|
||
/* Subtracting from integer_zero_node loses for long long. */
|
||
*conp = fold (build1 (NEGATE_EXPR, TREE_TYPE (*conp), *conp));
|
||
else
|
||
return 0;
|
||
}
|
||
return 1;
|
||
}
|
||
if (TREE_CONSTANT (TREE_OPERAND (in, 0)))
|
||
{
|
||
*conp = TREE_OPERAND (in, 0);
|
||
*varp = TREE_OPERAND (in, 1);
|
||
if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
|
||
&& TREE_TYPE (*varp) != outtype)
|
||
*varp = convert (outtype, *varp);
|
||
*varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
|
||
return 1;
|
||
}
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/* Combine two integer constants ARG1 and ARG2 under operation CODE
|
||
to produce a new constant.
|
||
|
||
If NOTRUNC is nonzero, do not truncate the result to fit the data type.
|
||
If FORSIZE is nonzero, compute overflow for unsigned types. */
|
||
|
||
static tree
|
||
int_const_binop (code, arg1, arg2, notrunc, forsize)
|
||
enum tree_code code;
|
||
register tree arg1, arg2;
|
||
int notrunc, forsize;
|
||
{
|
||
HOST_WIDE_INT int1l, int1h, int2l, int2h;
|
||
HOST_WIDE_INT low, hi;
|
||
HOST_WIDE_INT garbagel, garbageh;
|
||
register tree t;
|
||
int uns = TREE_UNSIGNED (TREE_TYPE (arg1));
|
||
int overflow = 0;
|
||
int no_overflow = 0;
|
||
|
||
int1l = TREE_INT_CST_LOW (arg1);
|
||
int1h = TREE_INT_CST_HIGH (arg1);
|
||
int2l = TREE_INT_CST_LOW (arg2);
|
||
int2h = TREE_INT_CST_HIGH (arg2);
|
||
|
||
switch (code)
|
||
{
|
||
case BIT_IOR_EXPR:
|
||
low = int1l | int2l, hi = int1h | int2h;
|
||
break;
|
||
|
||
case BIT_XOR_EXPR:
|
||
low = int1l ^ int2l, hi = int1h ^ int2h;
|
||
break;
|
||
|
||
case BIT_AND_EXPR:
|
||
low = int1l & int2l, hi = int1h & int2h;
|
||
break;
|
||
|
||
case BIT_ANDTC_EXPR:
|
||
low = int1l & ~int2l, hi = int1h & ~int2h;
|
||
break;
|
||
|
||
case RSHIFT_EXPR:
|
||
int2l = - int2l;
|
||
case LSHIFT_EXPR:
|
||
/* It's unclear from the C standard whether shifts can overflow.
|
||
The following code ignores overflow; perhaps a C standard
|
||
interpretation ruling is needed. */
|
||
lshift_double (int1l, int1h, int2l,
|
||
TYPE_PRECISION (TREE_TYPE (arg1)),
|
||
&low, &hi,
|
||
!uns);
|
||
no_overflow = 1;
|
||
break;
|
||
|
||
case RROTATE_EXPR:
|
||
int2l = - int2l;
|
||
case LROTATE_EXPR:
|
||
lrotate_double (int1l, int1h, int2l,
|
||
TYPE_PRECISION (TREE_TYPE (arg1)),
|
||
&low, &hi);
|
||
break;
|
||
|
||
case PLUS_EXPR:
|
||
overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
|
||
break;
|
||
|
||
case MINUS_EXPR:
|
||
neg_double (int2l, int2h, &low, &hi);
|
||
add_double (int1l, int1h, low, hi, &low, &hi);
|
||
overflow = overflow_sum_sign (hi, int2h, int1h);
|
||
break;
|
||
|
||
case MULT_EXPR:
|
||
overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
|
||
break;
|
||
|
||
case TRUNC_DIV_EXPR:
|
||
case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
|
||
case EXACT_DIV_EXPR:
|
||
/* This is a shortcut for a common special case. */
|
||
if (int2h == 0 && int2l > 0
|
||
&& ! TREE_CONSTANT_OVERFLOW (arg1)
|
||
&& ! TREE_CONSTANT_OVERFLOW (arg2)
|
||
&& int1h == 0 && int1l >= 0)
|
||
{
|
||
if (code == CEIL_DIV_EXPR)
|
||
int1l += int2l - 1;
|
||
low = int1l / int2l, hi = 0;
|
||
break;
|
||
}
|
||
|
||
/* ... fall through ... */
|
||
|
||
case ROUND_DIV_EXPR:
|
||
if (int2h == 0 && int2l == 1)
|
||
{
|
||
low = int1l, hi = int1h;
|
||
break;
|
||
}
|
||
if (int1l == int2l && int1h == int2h
|
||
&& ! (int1l == 0 && int1h == 0))
|
||
{
|
||
low = 1, hi = 0;
|
||
break;
|
||
}
|
||
overflow = div_and_round_double (code, uns,
|
||
int1l, int1h, int2l, int2h,
|
||
&low, &hi, &garbagel, &garbageh);
|
||
break;
|
||
|
||
case TRUNC_MOD_EXPR:
|
||
case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
|
||
/* This is a shortcut for a common special case. */
|
||
if (int2h == 0 && int2l > 0
|
||
&& ! TREE_CONSTANT_OVERFLOW (arg1)
|
||
&& ! TREE_CONSTANT_OVERFLOW (arg2)
|
||
&& int1h == 0 && int1l >= 0)
|
||
{
|
||
if (code == CEIL_MOD_EXPR)
|
||
int1l += int2l - 1;
|
||
low = int1l % int2l, hi = 0;
|
||
break;
|
||
}
|
||
|
||
/* ... fall through ... */
|
||
|
||
case ROUND_MOD_EXPR:
|
||
overflow = div_and_round_double (code, uns,
|
||
int1l, int1h, int2l, int2h,
|
||
&garbagel, &garbageh, &low, &hi);
|
||
break;
|
||
|
||
case MIN_EXPR:
|
||
case MAX_EXPR:
|
||
if (uns)
|
||
{
|
||
low = (((unsigned HOST_WIDE_INT) int1h
|
||
< (unsigned HOST_WIDE_INT) int2h)
|
||
|| (((unsigned HOST_WIDE_INT) int1h
|
||
== (unsigned HOST_WIDE_INT) int2h)
|
||
&& ((unsigned HOST_WIDE_INT) int1l
|
||
< (unsigned HOST_WIDE_INT) int2l)));
|
||
}
|
||
else
|
||
{
|
||
low = ((int1h < int2h)
|
||
|| ((int1h == int2h)
|
||
&& ((unsigned HOST_WIDE_INT) int1l
|
||
< (unsigned HOST_WIDE_INT) int2l)));
|
||
}
|
||
if (low == (code == MIN_EXPR))
|
||
low = int1l, hi = int1h;
|
||
else
|
||
low = int2l, hi = int2h;
|
||
break;
|
||
|
||
default:
|
||
abort ();
|
||
}
|
||
|
||
if (TREE_TYPE (arg1) == sizetype && hi == 0
|
||
&& low >= 0
|
||
&& (TYPE_MAX_VALUE (sizetype) == NULL
|
||
|| low <= TREE_INT_CST_LOW (TYPE_MAX_VALUE (sizetype)))
|
||
&& ! overflow
|
||
&& ! TREE_OVERFLOW (arg1) && ! TREE_OVERFLOW (arg2))
|
||
t = size_int (low);
|
||
else
|
||
{
|
||
t = build_int_2 (low, hi);
|
||
TREE_TYPE (t) = TREE_TYPE (arg1);
|
||
}
|
||
|
||
TREE_OVERFLOW (t)
|
||
= ((notrunc ? (!uns || forsize) && overflow
|
||
: force_fit_type (t, (!uns || forsize) && overflow) && ! no_overflow)
|
||
| TREE_OVERFLOW (arg1)
|
||
| TREE_OVERFLOW (arg2));
|
||
/* If we're doing a size calculation, unsigned arithmetic does overflow.
|
||
So check if force_fit_type truncated the value. */
|
||
if (forsize
|
||
&& ! TREE_OVERFLOW (t)
|
||
&& (TREE_INT_CST_HIGH (t) != hi
|
||
|| TREE_INT_CST_LOW (t) != low))
|
||
TREE_OVERFLOW (t) = 1;
|
||
TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t)
|
||
| TREE_CONSTANT_OVERFLOW (arg1)
|
||
| TREE_CONSTANT_OVERFLOW (arg2));
|
||
return t;
|
||
}
|
||
|
||
/* Combine two constants ARG1 and ARG2 under operation CODE
|
||
to produce a new constant.
|
||
We assume ARG1 and ARG2 have the same data type,
|
||
or at least are the same kind of constant and the same machine mode.
|
||
|
||
If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
|
||
|
||
static tree
|
||
const_binop (code, arg1, arg2, notrunc)
|
||
enum tree_code code;
|
||
register tree arg1, arg2;
|
||
int notrunc;
|
||
{
|
||
STRIP_NOPS (arg1); STRIP_NOPS (arg2);
|
||
|
||
if (TREE_CODE (arg1) == INTEGER_CST)
|
||
return int_const_binop (code, arg1, arg2, notrunc, 0);
|
||
|
||
#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
|
||
if (TREE_CODE (arg1) == REAL_CST)
|
||
{
|
||
REAL_VALUE_TYPE d1;
|
||
REAL_VALUE_TYPE d2;
|
||
int overflow = 0;
|
||
REAL_VALUE_TYPE value;
|
||
tree t;
|
||
|
||
d1 = TREE_REAL_CST (arg1);
|
||
d2 = TREE_REAL_CST (arg2);
|
||
|
||
/* If either operand is a NaN, just return it. Otherwise, set up
|
||
for floating-point trap; we return an overflow. */
|
||
if (REAL_VALUE_ISNAN (d1))
|
||
return arg1;
|
||
else if (REAL_VALUE_ISNAN (d2))
|
||
return arg2;
|
||
else if (setjmp (float_error))
|
||
{
|
||
t = copy_node (arg1);
|
||
overflow = 1;
|
||
goto got_float;
|
||
}
|
||
|
||
set_float_handler (float_error);
|
||
|
||
#ifdef REAL_ARITHMETIC
|
||
REAL_ARITHMETIC (value, code, d1, d2);
|
||
#else
|
||
switch (code)
|
||
{
|
||
case PLUS_EXPR:
|
||
value = d1 + d2;
|
||
break;
|
||
|
||
case MINUS_EXPR:
|
||
value = d1 - d2;
|
||
break;
|
||
|
||
case MULT_EXPR:
|
||
value = d1 * d2;
|
||
break;
|
||
|
||
case RDIV_EXPR:
|
||
#ifndef REAL_INFINITY
|
||
if (d2 == 0)
|
||
abort ();
|
||
#endif
|
||
|
||
value = d1 / d2;
|
||
break;
|
||
|
||
case MIN_EXPR:
|
||
value = MIN (d1, d2);
|
||
break;
|
||
|
||
case MAX_EXPR:
|
||
value = MAX (d1, d2);
|
||
break;
|
||
|
||
default:
|
||
abort ();
|
||
}
|
||
#endif /* no REAL_ARITHMETIC */
|
||
t = build_real (TREE_TYPE (arg1),
|
||
real_value_truncate (TYPE_MODE (TREE_TYPE (arg1)), value));
|
||
got_float:
|
||
set_float_handler (NULL_PTR);
|
||
|
||
TREE_OVERFLOW (t)
|
||
= (force_fit_type (t, overflow)
|
||
| TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2));
|
||
TREE_CONSTANT_OVERFLOW (t)
|
||
= TREE_OVERFLOW (t)
|
||
| TREE_CONSTANT_OVERFLOW (arg1)
|
||
| TREE_CONSTANT_OVERFLOW (arg2);
|
||
return t;
|
||
}
|
||
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
|
||
if (TREE_CODE (arg1) == COMPLEX_CST)
|
||
{
|
||
register tree type = TREE_TYPE (arg1);
|
||
register tree r1 = TREE_REALPART (arg1);
|
||
register tree i1 = TREE_IMAGPART (arg1);
|
||
register tree r2 = TREE_REALPART (arg2);
|
||
register tree i2 = TREE_IMAGPART (arg2);
|
||
register tree t;
|
||
|
||
switch (code)
|
||
{
|
||
case PLUS_EXPR:
|
||
t = build_complex (type,
|
||
const_binop (PLUS_EXPR, r1, r2, notrunc),
|
||
const_binop (PLUS_EXPR, i1, i2, notrunc));
|
||
break;
|
||
|
||
case MINUS_EXPR:
|
||
t = build_complex (type,
|
||
const_binop (MINUS_EXPR, r1, r2, notrunc),
|
||
const_binop (MINUS_EXPR, i1, i2, notrunc));
|
||
break;
|
||
|
||
case MULT_EXPR:
|
||
t = build_complex (type,
|
||
const_binop (MINUS_EXPR,
|
||
const_binop (MULT_EXPR,
|
||
r1, r2, notrunc),
|
||
const_binop (MULT_EXPR,
|
||
i1, i2, notrunc),
|
||
notrunc),
|
||
const_binop (PLUS_EXPR,
|
||
const_binop (MULT_EXPR,
|
||
r1, i2, notrunc),
|
||
const_binop (MULT_EXPR,
|
||
i1, r2, notrunc),
|
||
notrunc));
|
||
break;
|
||
|
||
case RDIV_EXPR:
|
||
{
|
||
register tree magsquared
|
||
= const_binop (PLUS_EXPR,
|
||
const_binop (MULT_EXPR, r2, r2, notrunc),
|
||
const_binop (MULT_EXPR, i2, i2, notrunc),
|
||
notrunc);
|
||
|
||
t = build_complex (type,
|
||
const_binop
|
||
(INTEGRAL_TYPE_P (TREE_TYPE (r1))
|
||
? TRUNC_DIV_EXPR : RDIV_EXPR,
|
||
const_binop (PLUS_EXPR,
|
||
const_binop (MULT_EXPR, r1, r2,
|
||
notrunc),
|
||
const_binop (MULT_EXPR, i1, i2,
|
||
notrunc),
|
||
notrunc),
|
||
magsquared, notrunc),
|
||
const_binop
|
||
(INTEGRAL_TYPE_P (TREE_TYPE (r1))
|
||
? TRUNC_DIV_EXPR : RDIV_EXPR,
|
||
const_binop (MINUS_EXPR,
|
||
const_binop (MULT_EXPR, i1, r2,
|
||
notrunc),
|
||
const_binop (MULT_EXPR, r1, i2,
|
||
notrunc),
|
||
notrunc),
|
||
magsquared, notrunc));
|
||
}
|
||
break;
|
||
|
||
default:
|
||
abort ();
|
||
}
|
||
return t;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/* Return an INTEGER_CST with value V . The type is determined by bit_p:
|
||
if it is zero, the type is taken from sizetype; if it is one, the type
|
||
is taken from bitsizetype. */
|
||
|
||
tree
|
||
size_int_wide (number, high, bit_p)
|
||
unsigned HOST_WIDE_INT number, high;
|
||
int bit_p;
|
||
{
|
||
register tree t;
|
||
/* Type-size nodes already made for small sizes. */
|
||
static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1][2];
|
||
|
||
if (number < 2*HOST_BITS_PER_WIDE_INT + 1 && ! high
|
||
&& size_table[number][bit_p] != 0)
|
||
return size_table[number][bit_p];
|
||
if (number < 2*HOST_BITS_PER_WIDE_INT + 1 && ! high)
|
||
{
|
||
push_obstacks_nochange ();
|
||
/* Make this a permanent node. */
|
||
end_temporary_allocation ();
|
||
t = build_int_2 (number, 0);
|
||
TREE_TYPE (t) = bit_p ? bitsizetype : sizetype;
|
||
size_table[number][bit_p] = t;
|
||
pop_obstacks ();
|
||
}
|
||
else
|
||
{
|
||
t = build_int_2 (number, high);
|
||
TREE_TYPE (t) = bit_p ? bitsizetype : sizetype;
|
||
TREE_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (t) = force_fit_type (t, 0);
|
||
}
|
||
return t;
|
||
}
|
||
|
||
/* Combine operands OP1 and OP2 with arithmetic operation CODE.
|
||
CODE is a tree code. Data type is taken from `sizetype',
|
||
If the operands are constant, so is the result. */
|
||
|
||
tree
|
||
size_binop (code, arg0, arg1)
|
||
enum tree_code code;
|
||
tree arg0, arg1;
|
||
{
|
||
/* Handle the special case of two integer constants faster. */
|
||
if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
|
||
{
|
||
/* And some specific cases even faster than that. */
|
||
if (code == PLUS_EXPR && integer_zerop (arg0))
|
||
return arg1;
|
||
else if ((code == MINUS_EXPR || code == PLUS_EXPR)
|
||
&& integer_zerop (arg1))
|
||
return arg0;
|
||
else if (code == MULT_EXPR && integer_onep (arg0))
|
||
return arg1;
|
||
|
||
/* Handle general case of two integer constants. */
|
||
return int_const_binop (code, arg0, arg1, 0, 1);
|
||
}
|
||
|
||
if (arg0 == error_mark_node || arg1 == error_mark_node)
|
||
return error_mark_node;
|
||
|
||
return fold (build (code, sizetype, arg0, arg1));
|
||
}
|
||
|
||
/* Combine operands OP1 and OP2 with arithmetic operation CODE.
|
||
CODE is a tree code. Data type is taken from `ssizetype',
|
||
If the operands are constant, so is the result. */
|
||
|
||
tree
|
||
ssize_binop (code, arg0, arg1)
|
||
enum tree_code code;
|
||
tree arg0, arg1;
|
||
{
|
||
/* Handle the special case of two integer constants faster. */
|
||
if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
|
||
{
|
||
/* And some specific cases even faster than that. */
|
||
if (code == PLUS_EXPR && integer_zerop (arg0))
|
||
return arg1;
|
||
else if ((code == MINUS_EXPR || code == PLUS_EXPR)
|
||
&& integer_zerop (arg1))
|
||
return arg0;
|
||
else if (code == MULT_EXPR && integer_onep (arg0))
|
||
return arg1;
|
||
|
||
/* Handle general case of two integer constants. We convert
|
||
arg0 to ssizetype because int_const_binop uses its type for the
|
||
return value. */
|
||
arg0 = convert (ssizetype, arg0);
|
||
return int_const_binop (code, arg0, arg1, 0, 0);
|
||
}
|
||
|
||
if (arg0 == error_mark_node || arg1 == error_mark_node)
|
||
return error_mark_node;
|
||
|
||
return fold (build (code, ssizetype, arg0, arg1));
|
||
}
|
||
|
||
/* Given T, a tree representing type conversion of ARG1, a constant,
|
||
return a constant tree representing the result of conversion. */
|
||
|
||
static tree
|
||
fold_convert (t, arg1)
|
||
register tree t;
|
||
register tree arg1;
|
||
{
|
||
register tree type = TREE_TYPE (t);
|
||
int overflow = 0;
|
||
|
||
if (POINTER_TYPE_P (type) || INTEGRAL_TYPE_P (type))
|
||
{
|
||
if (TREE_CODE (arg1) == INTEGER_CST)
|
||
{
|
||
/* If we would build a constant wider than GCC supports,
|
||
leave the conversion unfolded. */
|
||
if (TYPE_PRECISION (type) > 2 * HOST_BITS_PER_WIDE_INT)
|
||
return t;
|
||
|
||
/* Given an integer constant, make new constant with new type,
|
||
appropriately sign-extended or truncated. */
|
||
t = build_int_2 (TREE_INT_CST_LOW (arg1),
|
||
TREE_INT_CST_HIGH (arg1));
|
||
TREE_TYPE (t) = type;
|
||
/* Indicate an overflow if (1) ARG1 already overflowed,
|
||
or (2) force_fit_type indicates an overflow.
|
||
Tell force_fit_type that an overflow has already occurred
|
||
if ARG1 is a too-large unsigned value and T is signed.
|
||
But don't indicate an overflow if converting a pointer. */
|
||
TREE_OVERFLOW (t)
|
||
= ((force_fit_type (t,
|
||
(TREE_INT_CST_HIGH (arg1) < 0
|
||
&& (TREE_UNSIGNED (type)
|
||
< TREE_UNSIGNED (TREE_TYPE (arg1)))))
|
||
&& ! POINTER_TYPE_P (TREE_TYPE (arg1)))
|
||
|| TREE_OVERFLOW (arg1));
|
||
TREE_CONSTANT_OVERFLOW (t)
|
||
= TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
|
||
}
|
||
#if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
|
||
else if (TREE_CODE (arg1) == REAL_CST)
|
||
{
|
||
/* Don't initialize these, use assignments.
|
||
Initialized local aggregates don't work on old compilers. */
|
||
REAL_VALUE_TYPE x;
|
||
REAL_VALUE_TYPE l;
|
||
REAL_VALUE_TYPE u;
|
||
tree type1 = TREE_TYPE (arg1);
|
||
int no_upper_bound;
|
||
|
||
x = TREE_REAL_CST (arg1);
|
||
l = real_value_from_int_cst (type1, TYPE_MIN_VALUE (type));
|
||
|
||
no_upper_bound = (TYPE_MAX_VALUE (type) == NULL);
|
||
if (!no_upper_bound)
|
||
u = real_value_from_int_cst (type1, TYPE_MAX_VALUE (type));
|
||
|
||
/* See if X will be in range after truncation towards 0.
|
||
To compensate for truncation, move the bounds away from 0,
|
||
but reject if X exactly equals the adjusted bounds. */
|
||
#ifdef REAL_ARITHMETIC
|
||
REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
|
||
if (!no_upper_bound)
|
||
REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
|
||
#else
|
||
l--;
|
||
if (!no_upper_bound)
|
||
u++;
|
||
#endif
|
||
/* If X is a NaN, use zero instead and show we have an overflow.
|
||
Otherwise, range check. */
|
||
if (REAL_VALUE_ISNAN (x))
|
||
overflow = 1, x = dconst0;
|
||
else if (! (REAL_VALUES_LESS (l, x)
|
||
&& !no_upper_bound
|
||
&& REAL_VALUES_LESS (x, u)))
|
||
overflow = 1;
|
||
|
||
#ifndef REAL_ARITHMETIC
|
||
{
|
||
HOST_WIDE_INT low, high;
|
||
HOST_WIDE_INT half_word
|
||
= (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2);
|
||
|
||
if (x < 0)
|
||
x = -x;
|
||
|
||
high = (HOST_WIDE_INT) (x / half_word / half_word);
|
||
x -= (REAL_VALUE_TYPE) high * half_word * half_word;
|
||
if (x >= (REAL_VALUE_TYPE) half_word * half_word / 2)
|
||
{
|
||
low = x - (REAL_VALUE_TYPE) half_word * half_word / 2;
|
||
low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1);
|
||
}
|
||
else
|
||
low = (HOST_WIDE_INT) x;
|
||
if (TREE_REAL_CST (arg1) < 0)
|
||
neg_double (low, high, &low, &high);
|
||
t = build_int_2 (low, high);
|
||
}
|
||
#else
|
||
{
|
||
HOST_WIDE_INT low, high;
|
||
REAL_VALUE_TO_INT (&low, &high, x);
|
||
t = build_int_2 (low, high);
|
||
}
|
||
#endif
|
||
TREE_TYPE (t) = type;
|
||
TREE_OVERFLOW (t)
|
||
= TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
|
||
TREE_CONSTANT_OVERFLOW (t)
|
||
= TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
|
||
}
|
||
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
|
||
TREE_TYPE (t) = type;
|
||
}
|
||
else if (TREE_CODE (type) == REAL_TYPE)
|
||
{
|
||
#if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
|
||
if (TREE_CODE (arg1) == INTEGER_CST)
|
||
return build_real_from_int_cst (type, arg1);
|
||
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
|
||
if (TREE_CODE (arg1) == REAL_CST)
|
||
{
|
||
if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
|
||
{
|
||
t = arg1;
|
||
TREE_TYPE (arg1) = type;
|
||
return t;
|
||
}
|
||
else if (setjmp (float_error))
|
||
{
|
||
overflow = 1;
|
||
t = copy_node (arg1);
|
||
goto got_it;
|
||
}
|
||
set_float_handler (float_error);
|
||
|
||
t = build_real (type, real_value_truncate (TYPE_MODE (type),
|
||
TREE_REAL_CST (arg1)));
|
||
set_float_handler (NULL_PTR);
|
||
|
||
got_it:
|
||
TREE_OVERFLOW (t)
|
||
= TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
|
||
TREE_CONSTANT_OVERFLOW (t)
|
||
= TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
|
||
return t;
|
||
}
|
||
}
|
||
TREE_CONSTANT (t) = 1;
|
||
return t;
|
||
}
|
||
|
||
/* Return an expr equal to X but certainly not valid as an lvalue.
|
||
Also make sure it is not valid as an null pointer constant. */
|
||
|
||
tree
|
||
non_lvalue (x)
|
||
tree x;
|
||
{
|
||
tree result;
|
||
|
||
/* These things are certainly not lvalues. */
|
||
if (TREE_CODE (x) == NON_LVALUE_EXPR
|
||
|| TREE_CODE (x) == INTEGER_CST
|
||
|| TREE_CODE (x) == REAL_CST
|
||
|| TREE_CODE (x) == STRING_CST
|
||
|| TREE_CODE (x) == ADDR_EXPR)
|
||
{
|
||
if (TREE_CODE (x) == INTEGER_CST && integer_zerop (x))
|
||
{
|
||
/* Use NOP_EXPR instead of NON_LVALUE_EXPR
|
||
so convert_for_assignment won't strip it.
|
||
This is so this 0 won't be treated as a null pointer constant. */
|
||
result = build1 (NOP_EXPR, TREE_TYPE (x), x);
|
||
TREE_CONSTANT (result) = TREE_CONSTANT (x);
|
||
return result;
|
||
}
|
||
return x;
|
||
}
|
||
|
||
result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x);
|
||
TREE_CONSTANT (result) = TREE_CONSTANT (x);
|
||
return result;
|
||
}
|
||
|
||
/* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
|
||
Zero means allow extended lvalues. */
|
||
|
||
int pedantic_lvalues;
|
||
|
||
/* When pedantic, return an expr equal to X but certainly not valid as a
|
||
pedantic lvalue. Otherwise, return X. */
|
||
|
||
tree
|
||
pedantic_non_lvalue (x)
|
||
tree x;
|
||
{
|
||
if (pedantic_lvalues)
|
||
return non_lvalue (x);
|
||
else
|
||
return x;
|
||
}
|
||
|
||
/* Given a tree comparison code, return the code that is the logical inverse
|
||
of the given code. It is not safe to do this for floating-point
|
||
comparisons, except for NE_EXPR and EQ_EXPR. */
|
||
|
||
static enum tree_code
|
||
invert_tree_comparison (code)
|
||
enum tree_code code;
|
||
{
|
||
switch (code)
|
||
{
|
||
case EQ_EXPR:
|
||
return NE_EXPR;
|
||
case NE_EXPR:
|
||
return EQ_EXPR;
|
||
case GT_EXPR:
|
||
return LE_EXPR;
|
||
case GE_EXPR:
|
||
return LT_EXPR;
|
||
case LT_EXPR:
|
||
return GE_EXPR;
|
||
case LE_EXPR:
|
||
return GT_EXPR;
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
|
||
/* Similar, but return the comparison that results if the operands are
|
||
swapped. This is safe for floating-point. */
|
||
|
||
static enum tree_code
|
||
swap_tree_comparison (code)
|
||
enum tree_code code;
|
||
{
|
||
switch (code)
|
||
{
|
||
case EQ_EXPR:
|
||
case NE_EXPR:
|
||
return code;
|
||
case GT_EXPR:
|
||
return LT_EXPR;
|
||
case GE_EXPR:
|
||
return LE_EXPR;
|
||
case LT_EXPR:
|
||
return GT_EXPR;
|
||
case LE_EXPR:
|
||
return GE_EXPR;
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
|
||
/* Return nonzero if CODE is a tree code that represents a truth value. */
|
||
|
||
static int
|
||
truth_value_p (code)
|
||
enum tree_code code;
|
||
{
|
||
return (TREE_CODE_CLASS (code) == '<'
|
||
|| code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
|
||
|| code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
|
||
|| code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR);
|
||
}
|
||
|
||
/* Return nonzero if two operands are necessarily equal.
|
||
If ONLY_CONST is non-zero, only return non-zero for constants.
|
||
This function tests whether the operands are indistinguishable;
|
||
it does not test whether they are equal using C's == operation.
|
||
The distinction is important for IEEE floating point, because
|
||
(1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
|
||
(2) two NaNs may be indistinguishable, but NaN!=NaN. */
|
||
|
||
int
|
||
operand_equal_p (arg0, arg1, only_const)
|
||
tree arg0, arg1;
|
||
int only_const;
|
||
{
|
||
/* If both types don't have the same signedness, then we can't consider
|
||
them equal. We must check this before the STRIP_NOPS calls
|
||
because they may change the signedness of the arguments. */
|
||
if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1)))
|
||
return 0;
|
||
|
||
STRIP_NOPS (arg0);
|
||
STRIP_NOPS (arg1);
|
||
|
||
if (TREE_CODE (arg0) != TREE_CODE (arg1)
|
||
/* This is needed for conversions and for COMPONENT_REF.
|
||
Might as well play it safe and always test this. */
|
||
|| TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
|
||
return 0;
|
||
|
||
/* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
|
||
We don't care about side effects in that case because the SAVE_EXPR
|
||
takes care of that for us. In all other cases, two expressions are
|
||
equal if they have no side effects. If we have two identical
|
||
expressions with side effects that should be treated the same due
|
||
to the only side effects being identical SAVE_EXPR's, that will
|
||
be detected in the recursive calls below. */
|
||
if (arg0 == arg1 && ! only_const
|
||
&& (TREE_CODE (arg0) == SAVE_EXPR
|
||
|| (! TREE_SIDE_EFFECTS (arg0) && ! TREE_SIDE_EFFECTS (arg1))))
|
||
return 1;
|
||
|
||
/* Next handle constant cases, those for which we can return 1 even
|
||
if ONLY_CONST is set. */
|
||
if (TREE_CONSTANT (arg0) && TREE_CONSTANT (arg1))
|
||
switch (TREE_CODE (arg0))
|
||
{
|
||
case INTEGER_CST:
|
||
return (! TREE_CONSTANT_OVERFLOW (arg0)
|
||
&& ! TREE_CONSTANT_OVERFLOW (arg1)
|
||
&& TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1)
|
||
&& TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1));
|
||
|
||
case REAL_CST:
|
||
return (! TREE_CONSTANT_OVERFLOW (arg0)
|
||
&& ! TREE_CONSTANT_OVERFLOW (arg1)
|
||
&& REAL_VALUES_IDENTICAL (TREE_REAL_CST (arg0),
|
||
TREE_REAL_CST (arg1)));
|
||
|
||
case COMPLEX_CST:
|
||
return (operand_equal_p (TREE_REALPART (arg0), TREE_REALPART (arg1),
|
||
only_const)
|
||
&& operand_equal_p (TREE_IMAGPART (arg0), TREE_IMAGPART (arg1),
|
||
only_const));
|
||
|
||
case STRING_CST:
|
||
return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1)
|
||
&& ! strncmp (TREE_STRING_POINTER (arg0),
|
||
TREE_STRING_POINTER (arg1),
|
||
TREE_STRING_LENGTH (arg0)));
|
||
|
||
case ADDR_EXPR:
|
||
return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
|
||
0);
|
||
default:
|
||
break;
|
||
}
|
||
|
||
if (only_const)
|
||
return 0;
|
||
|
||
switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
|
||
{
|
||
case '1':
|
||
/* Two conversions are equal only if signedness and modes match. */
|
||
if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR)
|
||
&& (TREE_UNSIGNED (TREE_TYPE (arg0))
|
||
!= TREE_UNSIGNED (TREE_TYPE (arg1))))
|
||
return 0;
|
||
|
||
return operand_equal_p (TREE_OPERAND (arg0, 0),
|
||
TREE_OPERAND (arg1, 0), 0);
|
||
|
||
case '<':
|
||
case '2':
|
||
if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1),
|
||
0))
|
||
return 1;
|
||
|
||
/* For commutative ops, allow the other order. */
|
||
return ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MULT_EXPR
|
||
|| TREE_CODE (arg0) == MIN_EXPR || TREE_CODE (arg0) == MAX_EXPR
|
||
|| TREE_CODE (arg0) == BIT_IOR_EXPR
|
||
|| TREE_CODE (arg0) == BIT_XOR_EXPR
|
||
|| TREE_CODE (arg0) == BIT_AND_EXPR
|
||
|| TREE_CODE (arg0) == NE_EXPR || TREE_CODE (arg0) == EQ_EXPR)
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 0),
|
||
TREE_OPERAND (arg1, 1), 0)
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 1),
|
||
TREE_OPERAND (arg1, 0), 0));
|
||
|
||
case 'r':
|
||
switch (TREE_CODE (arg0))
|
||
{
|
||
case INDIRECT_REF:
|
||
return operand_equal_p (TREE_OPERAND (arg0, 0),
|
||
TREE_OPERAND (arg1, 0), 0);
|
||
|
||
case COMPONENT_REF:
|
||
case ARRAY_REF:
|
||
return (operand_equal_p (TREE_OPERAND (arg0, 0),
|
||
TREE_OPERAND (arg1, 0), 0)
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 1),
|
||
TREE_OPERAND (arg1, 1), 0));
|
||
|
||
case BIT_FIELD_REF:
|
||
return (operand_equal_p (TREE_OPERAND (arg0, 0),
|
||
TREE_OPERAND (arg1, 0), 0)
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 1),
|
||
TREE_OPERAND (arg1, 1), 0)
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 2),
|
||
TREE_OPERAND (arg1, 2), 0));
|
||
default:
|
||
return 0;
|
||
}
|
||
|
||
default:
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
/* Similar to operand_equal_p, but see if ARG0 might have been made by
|
||
shorten_compare from ARG1 when ARG1 was being compared with OTHER.
|
||
|
||
When in doubt, return 0. */
|
||
|
||
static int
|
||
operand_equal_for_comparison_p (arg0, arg1, other)
|
||
tree arg0, arg1;
|
||
tree other;
|
||
{
|
||
int unsignedp1, unsignedpo;
|
||
tree primarg0, primarg1, primother;
|
||
unsigned correct_width;
|
||
|
||
if (operand_equal_p (arg0, arg1, 0))
|
||
return 1;
|
||
|
||
if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))
|
||
|| ! INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
|
||
return 0;
|
||
|
||
/* Discard any conversions that don't change the modes of ARG0 and ARG1
|
||
and see if the inner values are the same. This removes any
|
||
signedness comparison, which doesn't matter here. */
|
||
primarg0 = arg0, primarg1 = arg1;
|
||
STRIP_NOPS (primarg0); STRIP_NOPS (primarg1);
|
||
if (operand_equal_p (primarg0, primarg1, 0))
|
||
return 1;
|
||
|
||
/* Duplicate what shorten_compare does to ARG1 and see if that gives the
|
||
actual comparison operand, ARG0.
|
||
|
||
First throw away any conversions to wider types
|
||
already present in the operands. */
|
||
|
||
primarg1 = get_narrower (arg1, &unsignedp1);
|
||
primother = get_narrower (other, &unsignedpo);
|
||
|
||
correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
|
||
if (unsignedp1 == unsignedpo
|
||
&& TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
|
||
&& TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
|
||
{
|
||
tree type = TREE_TYPE (arg0);
|
||
|
||
/* Make sure shorter operand is extended the right way
|
||
to match the longer operand. */
|
||
primarg1 = convert (signed_or_unsigned_type (unsignedp1,
|
||
TREE_TYPE (primarg1)),
|
||
primarg1);
|
||
|
||
if (operand_equal_p (arg0, convert (type, primarg1), 0))
|
||
return 1;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* See if ARG is an expression that is either a comparison or is performing
|
||
arithmetic on comparisons. The comparisons must only be comparing
|
||
two different values, which will be stored in *CVAL1 and *CVAL2; if
|
||
they are non-zero it means that some operands have already been found.
|
||
No variables may be used anywhere else in the expression except in the
|
||
comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
|
||
the expression and save_expr needs to be called with CVAL1 and CVAL2.
|
||
|
||
If this is true, return 1. Otherwise, return zero. */
|
||
|
||
static int
|
||
twoval_comparison_p (arg, cval1, cval2, save_p)
|
||
tree arg;
|
||
tree *cval1, *cval2;
|
||
int *save_p;
|
||
{
|
||
enum tree_code code = TREE_CODE (arg);
|
||
char class = TREE_CODE_CLASS (code);
|
||
|
||
/* We can handle some of the 'e' cases here. */
|
||
if (class == 'e' && code == TRUTH_NOT_EXPR)
|
||
class = '1';
|
||
else if (class == 'e'
|
||
&& (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR
|
||
|| code == COMPOUND_EXPR))
|
||
class = '2';
|
||
|
||
/* ??? Disable this since the SAVE_EXPR might already be in use outside
|
||
the expression. There may be no way to make this work, but it needs
|
||
to be looked at again for 2.6. */
|
||
#if 0
|
||
else if (class == 'e' && code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0)
|
||
{
|
||
/* If we've already found a CVAL1 or CVAL2, this expression is
|
||
two complex to handle. */
|
||
if (*cval1 || *cval2)
|
||
return 0;
|
||
|
||
class = '1';
|
||
*save_p = 1;
|
||
}
|
||
#endif
|
||
|
||
switch (class)
|
||
{
|
||
case '1':
|
||
return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p);
|
||
|
||
case '2':
|
||
return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p)
|
||
&& twoval_comparison_p (TREE_OPERAND (arg, 1),
|
||
cval1, cval2, save_p));
|
||
|
||
case 'c':
|
||
return 1;
|
||
|
||
case 'e':
|
||
if (code == COND_EXPR)
|
||
return (twoval_comparison_p (TREE_OPERAND (arg, 0),
|
||
cval1, cval2, save_p)
|
||
&& twoval_comparison_p (TREE_OPERAND (arg, 1),
|
||
cval1, cval2, save_p)
|
||
&& twoval_comparison_p (TREE_OPERAND (arg, 2),
|
||
cval1, cval2, save_p));
|
||
return 0;
|
||
|
||
case '<':
|
||
/* First see if we can handle the first operand, then the second. For
|
||
the second operand, we know *CVAL1 can't be zero. It must be that
|
||
one side of the comparison is each of the values; test for the
|
||
case where this isn't true by failing if the two operands
|
||
are the same. */
|
||
|
||
if (operand_equal_p (TREE_OPERAND (arg, 0),
|
||
TREE_OPERAND (arg, 1), 0))
|
||
return 0;
|
||
|
||
if (*cval1 == 0)
|
||
*cval1 = TREE_OPERAND (arg, 0);
|
||
else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0))
|
||
;
|
||
else if (*cval2 == 0)
|
||
*cval2 = TREE_OPERAND (arg, 0);
|
||
else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0))
|
||
;
|
||
else
|
||
return 0;
|
||
|
||
if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0))
|
||
;
|
||
else if (*cval2 == 0)
|
||
*cval2 = TREE_OPERAND (arg, 1);
|
||
else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0))
|
||
;
|
||
else
|
||
return 0;
|
||
|
||
return 1;
|
||
|
||
default:
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
/* ARG is a tree that is known to contain just arithmetic operations and
|
||
comparisons. Evaluate the operations in the tree substituting NEW0 for
|
||
any occurrence of OLD0 as an operand of a comparison and likewise for
|
||
NEW1 and OLD1. */
|
||
|
||
static tree
|
||
eval_subst (arg, old0, new0, old1, new1)
|
||
tree arg;
|
||
tree old0, new0, old1, new1;
|
||
{
|
||
tree type = TREE_TYPE (arg);
|
||
enum tree_code code = TREE_CODE (arg);
|
||
char class = TREE_CODE_CLASS (code);
|
||
|
||
/* We can handle some of the 'e' cases here. */
|
||
if (class == 'e' && code == TRUTH_NOT_EXPR)
|
||
class = '1';
|
||
else if (class == 'e'
|
||
&& (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR))
|
||
class = '2';
|
||
|
||
switch (class)
|
||
{
|
||
case '1':
|
||
return fold (build1 (code, type,
|
||
eval_subst (TREE_OPERAND (arg, 0),
|
||
old0, new0, old1, new1)));
|
||
|
||
case '2':
|
||
return fold (build (code, type,
|
||
eval_subst (TREE_OPERAND (arg, 0),
|
||
old0, new0, old1, new1),
|
||
eval_subst (TREE_OPERAND (arg, 1),
|
||
old0, new0, old1, new1)));
|
||
|
||
case 'e':
|
||
switch (code)
|
||
{
|
||
case SAVE_EXPR:
|
||
return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1);
|
||
|
||
case COMPOUND_EXPR:
|
||
return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1);
|
||
|
||
case COND_EXPR:
|
||
return fold (build (code, type,
|
||
eval_subst (TREE_OPERAND (arg, 0),
|
||
old0, new0, old1, new1),
|
||
eval_subst (TREE_OPERAND (arg, 1),
|
||
old0, new0, old1, new1),
|
||
eval_subst (TREE_OPERAND (arg, 2),
|
||
old0, new0, old1, new1)));
|
||
default:
|
||
break;
|
||
}
|
||
/* fall through (???) */
|
||
|
||
case '<':
|
||
{
|
||
tree arg0 = TREE_OPERAND (arg, 0);
|
||
tree arg1 = TREE_OPERAND (arg, 1);
|
||
|
||
/* We need to check both for exact equality and tree equality. The
|
||
former will be true if the operand has a side-effect. In that
|
||
case, we know the operand occurred exactly once. */
|
||
|
||
if (arg0 == old0 || operand_equal_p (arg0, old0, 0))
|
||
arg0 = new0;
|
||
else if (arg0 == old1 || operand_equal_p (arg0, old1, 0))
|
||
arg0 = new1;
|
||
|
||
if (arg1 == old0 || operand_equal_p (arg1, old0, 0))
|
||
arg1 = new0;
|
||
else if (arg1 == old1 || operand_equal_p (arg1, old1, 0))
|
||
arg1 = new1;
|
||
|
||
return fold (build (code, type, arg0, arg1));
|
||
}
|
||
|
||
default:
|
||
return arg;
|
||
}
|
||
}
|
||
|
||
/* Return a tree for the case when the result of an expression is RESULT
|
||
converted to TYPE and OMITTED was previously an operand of the expression
|
||
but is now not needed (e.g., we folded OMITTED * 0).
|
||
|
||
If OMITTED has side effects, we must evaluate it. Otherwise, just do
|
||
the conversion of RESULT to TYPE. */
|
||
|
||
static tree
|
||
omit_one_operand (type, result, omitted)
|
||
tree type, result, omitted;
|
||
{
|
||
tree t = convert (type, result);
|
||
|
||
if (TREE_SIDE_EFFECTS (omitted))
|
||
return build (COMPOUND_EXPR, type, omitted, t);
|
||
|
||
return non_lvalue (t);
|
||
}
|
||
|
||
/* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
|
||
|
||
static tree
|
||
pedantic_omit_one_operand (type, result, omitted)
|
||
tree type, result, omitted;
|
||
{
|
||
tree t = convert (type, result);
|
||
|
||
if (TREE_SIDE_EFFECTS (omitted))
|
||
return build (COMPOUND_EXPR, type, omitted, t);
|
||
|
||
return pedantic_non_lvalue (t);
|
||
}
|
||
|
||
|
||
|
||
/* Return a simplified tree node for the truth-negation of ARG. This
|
||
never alters ARG itself. We assume that ARG is an operation that
|
||
returns a truth value (0 or 1). */
|
||
|
||
tree
|
||
invert_truthvalue (arg)
|
||
tree arg;
|
||
{
|
||
tree type = TREE_TYPE (arg);
|
||
enum tree_code code = TREE_CODE (arg);
|
||
|
||
if (code == ERROR_MARK)
|
||
return arg;
|
||
|
||
/* If this is a comparison, we can simply invert it, except for
|
||
floating-point non-equality comparisons, in which case we just
|
||
enclose a TRUTH_NOT_EXPR around what we have. */
|
||
|
||
if (TREE_CODE_CLASS (code) == '<')
|
||
{
|
||
if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0)))
|
||
&& code != NE_EXPR && code != EQ_EXPR)
|
||
return build1 (TRUTH_NOT_EXPR, type, arg);
|
||
else
|
||
return build (invert_tree_comparison (code), type,
|
||
TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
|
||
}
|
||
|
||
switch (code)
|
||
{
|
||
case INTEGER_CST:
|
||
return convert (type, build_int_2 (TREE_INT_CST_LOW (arg) == 0
|
||
&& TREE_INT_CST_HIGH (arg) == 0, 0));
|
||
|
||
case TRUTH_AND_EXPR:
|
||
return build (TRUTH_OR_EXPR, type,
|
||
invert_truthvalue (TREE_OPERAND (arg, 0)),
|
||
invert_truthvalue (TREE_OPERAND (arg, 1)));
|
||
|
||
case TRUTH_OR_EXPR:
|
||
return build (TRUTH_AND_EXPR, type,
|
||
invert_truthvalue (TREE_OPERAND (arg, 0)),
|
||
invert_truthvalue (TREE_OPERAND (arg, 1)));
|
||
|
||
case TRUTH_XOR_EXPR:
|
||
/* Here we can invert either operand. We invert the first operand
|
||
unless the second operand is a TRUTH_NOT_EXPR in which case our
|
||
result is the XOR of the first operand with the inside of the
|
||
negation of the second operand. */
|
||
|
||
if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
|
||
return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
|
||
TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
|
||
else
|
||
return build (TRUTH_XOR_EXPR, type,
|
||
invert_truthvalue (TREE_OPERAND (arg, 0)),
|
||
TREE_OPERAND (arg, 1));
|
||
|
||
case TRUTH_ANDIF_EXPR:
|
||
return build (TRUTH_ORIF_EXPR, type,
|
||
invert_truthvalue (TREE_OPERAND (arg, 0)),
|
||
invert_truthvalue (TREE_OPERAND (arg, 1)));
|
||
|
||
case TRUTH_ORIF_EXPR:
|
||
return build (TRUTH_ANDIF_EXPR, type,
|
||
invert_truthvalue (TREE_OPERAND (arg, 0)),
|
||
invert_truthvalue (TREE_OPERAND (arg, 1)));
|
||
|
||
case TRUTH_NOT_EXPR:
|
||
return TREE_OPERAND (arg, 0);
|
||
|
||
case COND_EXPR:
|
||
return build (COND_EXPR, type, TREE_OPERAND (arg, 0),
|
||
invert_truthvalue (TREE_OPERAND (arg, 1)),
|
||
invert_truthvalue (TREE_OPERAND (arg, 2)));
|
||
|
||
case COMPOUND_EXPR:
|
||
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
|
||
invert_truthvalue (TREE_OPERAND (arg, 1)));
|
||
|
||
case NON_LVALUE_EXPR:
|
||
return invert_truthvalue (TREE_OPERAND (arg, 0));
|
||
|
||
case NOP_EXPR:
|
||
case CONVERT_EXPR:
|
||
case FLOAT_EXPR:
|
||
return build1 (TREE_CODE (arg), type,
|
||
invert_truthvalue (TREE_OPERAND (arg, 0)));
|
||
|
||
case BIT_AND_EXPR:
|
||
if (!integer_onep (TREE_OPERAND (arg, 1)))
|
||
break;
|
||
return build (EQ_EXPR, type, arg, convert (type, integer_zero_node));
|
||
|
||
case SAVE_EXPR:
|
||
return build1 (TRUTH_NOT_EXPR, type, arg);
|
||
|
||
case CLEANUP_POINT_EXPR:
|
||
return build1 (CLEANUP_POINT_EXPR, type,
|
||
invert_truthvalue (TREE_OPERAND (arg, 0)));
|
||
|
||
default:
|
||
break;
|
||
}
|
||
if (TREE_CODE (TREE_TYPE (arg)) != BOOLEAN_TYPE)
|
||
abort ();
|
||
return build1 (TRUTH_NOT_EXPR, type, arg);
|
||
}
|
||
|
||
/* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
|
||
operands are another bit-wise operation with a common input. If so,
|
||
distribute the bit operations to save an operation and possibly two if
|
||
constants are involved. For example, convert
|
||
(A | B) & (A | C) into A | (B & C)
|
||
Further simplification will occur if B and C are constants.
|
||
|
||
If this optimization cannot be done, 0 will be returned. */
|
||
|
||
static tree
|
||
distribute_bit_expr (code, type, arg0, arg1)
|
||
enum tree_code code;
|
||
tree type;
|
||
tree arg0, arg1;
|
||
{
|
||
tree common;
|
||
tree left, right;
|
||
|
||
if (TREE_CODE (arg0) != TREE_CODE (arg1)
|
||
|| TREE_CODE (arg0) == code
|
||
|| (TREE_CODE (arg0) != BIT_AND_EXPR
|
||
&& TREE_CODE (arg0) != BIT_IOR_EXPR))
|
||
return 0;
|
||
|
||
if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0))
|
||
{
|
||
common = TREE_OPERAND (arg0, 0);
|
||
left = TREE_OPERAND (arg0, 1);
|
||
right = TREE_OPERAND (arg1, 1);
|
||
}
|
||
else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0))
|
||
{
|
||
common = TREE_OPERAND (arg0, 0);
|
||
left = TREE_OPERAND (arg0, 1);
|
||
right = TREE_OPERAND (arg1, 0);
|
||
}
|
||
else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0))
|
||
{
|
||
common = TREE_OPERAND (arg0, 1);
|
||
left = TREE_OPERAND (arg0, 0);
|
||
right = TREE_OPERAND (arg1, 1);
|
||
}
|
||
else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0))
|
||
{
|
||
common = TREE_OPERAND (arg0, 1);
|
||
left = TREE_OPERAND (arg0, 0);
|
||
right = TREE_OPERAND (arg1, 0);
|
||
}
|
||
else
|
||
return 0;
|
||
|
||
return fold (build (TREE_CODE (arg0), type, common,
|
||
fold (build (code, type, left, right))));
|
||
}
|
||
|
||
/* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
|
||
starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */
|
||
|
||
static tree
|
||
make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp)
|
||
tree inner;
|
||
tree type;
|
||
int bitsize, bitpos;
|
||
int unsignedp;
|
||
{
|
||
tree result = build (BIT_FIELD_REF, type, inner,
|
||
size_int (bitsize), bitsize_int (bitpos, 0L));
|
||
|
||
TREE_UNSIGNED (result) = unsignedp;
|
||
|
||
return result;
|
||
}
|
||
|
||
/* Optimize a bit-field compare.
|
||
|
||
There are two cases: First is a compare against a constant and the
|
||
second is a comparison of two items where the fields are at the same
|
||
bit position relative to the start of a chunk (byte, halfword, word)
|
||
large enough to contain it. In these cases we can avoid the shift
|
||
implicit in bitfield extractions.
|
||
|
||
For constants, we emit a compare of the shifted constant with the
|
||
BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
|
||
compared. For two fields at the same position, we do the ANDs with the
|
||
similar mask and compare the result of the ANDs.
|
||
|
||
CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
|
||
COMPARE_TYPE is the type of the comparison, and LHS and RHS
|
||
are the left and right operands of the comparison, respectively.
|
||
|
||
If the optimization described above can be done, we return the resulting
|
||
tree. Otherwise we return zero. */
|
||
|
||
static tree
|
||
optimize_bit_field_compare (code, compare_type, lhs, rhs)
|
||
enum tree_code code;
|
||
tree compare_type;
|
||
tree lhs, rhs;
|
||
{
|
||
int lbitpos, lbitsize, rbitpos, rbitsize;
|
||
int lnbitpos, lnbitsize, rnbitpos = 0, rnbitsize = 0;
|
||
tree type = TREE_TYPE (lhs);
|
||
tree signed_type, unsigned_type;
|
||
int const_p = TREE_CODE (rhs) == INTEGER_CST;
|
||
enum machine_mode lmode, rmode, lnmode, rnmode = VOIDmode;
|
||
int lunsignedp, runsignedp;
|
||
int lvolatilep = 0, rvolatilep = 0;
|
||
int alignment;
|
||
tree linner, rinner = NULL_TREE;
|
||
tree mask;
|
||
tree offset;
|
||
|
||
/* Get all the information about the extractions being done. If the bit size
|
||
if the same as the size of the underlying object, we aren't doing an
|
||
extraction at all and so can do nothing. */
|
||
linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
|
||
&lunsignedp, &lvolatilep, &alignment);
|
||
if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
|
||
|| offset != 0)
|
||
return 0;
|
||
|
||
if (!const_p)
|
||
{
|
||
/* If this is not a constant, we can only do something if bit positions,
|
||
sizes, and signedness are the same. */
|
||
rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, &rmode,
|
||
&runsignedp, &rvolatilep, &alignment);
|
||
|
||
if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize
|
||
|| lunsignedp != runsignedp || offset != 0)
|
||
return 0;
|
||
}
|
||
|
||
/* See if we can find a mode to refer to this field. We should be able to,
|
||
but fail if we can't. */
|
||
lnmode = get_best_mode (lbitsize, lbitpos,
|
||
TYPE_ALIGN (TREE_TYPE (linner)), word_mode,
|
||
lvolatilep);
|
||
if (lnmode == VOIDmode)
|
||
return 0;
|
||
|
||
/* Set signed and unsigned types of the precision of this mode for the
|
||
shifts below. */
|
||
signed_type = type_for_mode (lnmode, 0);
|
||
unsigned_type = type_for_mode (lnmode, 1);
|
||
|
||
if (! const_p)
|
||
{
|
||
rnmode = get_best_mode (rbitsize, rbitpos,
|
||
TYPE_ALIGN (TREE_TYPE (rinner)), word_mode,
|
||
rvolatilep);
|
||
if (rnmode == VOIDmode)
|
||
return 0;
|
||
}
|
||
|
||
/* Compute the bit position and size for the new reference and our offset
|
||
within it. If the new reference is the same size as the original, we
|
||
won't optimize anything, so return zero. */
|
||
lnbitsize = GET_MODE_BITSIZE (lnmode);
|
||
lnbitpos = lbitpos & ~ (lnbitsize - 1);
|
||
lbitpos -= lnbitpos;
|
||
if (lnbitsize == lbitsize)
|
||
return 0;
|
||
|
||
if (! const_p)
|
||
{
|
||
rnbitsize = GET_MODE_BITSIZE (rnmode);
|
||
rnbitpos = rbitpos & ~ (rnbitsize - 1);
|
||
rbitpos -= rnbitpos;
|
||
if (rnbitsize == rbitsize)
|
||
return 0;
|
||
}
|
||
|
||
if (BYTES_BIG_ENDIAN)
|
||
lbitpos = lnbitsize - lbitsize - lbitpos;
|
||
|
||
/* Make the mask to be used against the extracted field. */
|
||
mask = build_int_2 (~0, ~0);
|
||
TREE_TYPE (mask) = unsigned_type;
|
||
force_fit_type (mask, 0);
|
||
mask = convert (unsigned_type, mask);
|
||
mask = const_binop (LSHIFT_EXPR, mask, size_int (lnbitsize - lbitsize), 0);
|
||
mask = const_binop (RSHIFT_EXPR, mask,
|
||
size_int (lnbitsize - lbitsize - lbitpos), 0);
|
||
|
||
if (! const_p)
|
||
/* If not comparing with constant, just rework the comparison
|
||
and return. */
|
||
return build (code, compare_type,
|
||
build (BIT_AND_EXPR, unsigned_type,
|
||
make_bit_field_ref (linner, unsigned_type,
|
||
lnbitsize, lnbitpos, 1),
|
||
mask),
|
||
build (BIT_AND_EXPR, unsigned_type,
|
||
make_bit_field_ref (rinner, unsigned_type,
|
||
rnbitsize, rnbitpos, 1),
|
||
mask));
|
||
|
||
/* Otherwise, we are handling the constant case. See if the constant is too
|
||
big for the field. Warn and return a tree of for 0 (false) if so. We do
|
||
this not only for its own sake, but to avoid having to test for this
|
||
error case below. If we didn't, we might generate wrong code.
|
||
|
||
For unsigned fields, the constant shifted right by the field length should
|
||
be all zero. For signed fields, the high-order bits should agree with
|
||
the sign bit. */
|
||
|
||
if (lunsignedp)
|
||
{
|
||
if (! integer_zerop (const_binop (RSHIFT_EXPR,
|
||
convert (unsigned_type, rhs),
|
||
size_int (lbitsize), 0)))
|
||
{
|
||
warning ("comparison is always %s due to width of bitfield",
|
||
code == NE_EXPR ? "one" : "zero");
|
||
return convert (compare_type,
|
||
(code == NE_EXPR
|
||
? integer_one_node : integer_zero_node));
|
||
}
|
||
}
|
||
else
|
||
{
|
||
tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs),
|
||
size_int (lbitsize - 1), 0);
|
||
if (! integer_zerop (tem) && ! integer_all_onesp (tem))
|
||
{
|
||
warning ("comparison is always %s due to width of bitfield",
|
||
code == NE_EXPR ? "one" : "zero");
|
||
return convert (compare_type,
|
||
(code == NE_EXPR
|
||
? integer_one_node : integer_zero_node));
|
||
}
|
||
}
|
||
|
||
/* Single-bit compares should always be against zero. */
|
||
if (lbitsize == 1 && ! integer_zerop (rhs))
|
||
{
|
||
code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR;
|
||
rhs = convert (type, integer_zero_node);
|
||
}
|
||
|
||
/* Make a new bitfield reference, shift the constant over the
|
||
appropriate number of bits and mask it with the computed mask
|
||
(in case this was a signed field). If we changed it, make a new one. */
|
||
lhs = make_bit_field_ref (linner, unsigned_type, lnbitsize, lnbitpos, 1);
|
||
if (lvolatilep)
|
||
{
|
||
TREE_SIDE_EFFECTS (lhs) = 1;
|
||
TREE_THIS_VOLATILE (lhs) = 1;
|
||
}
|
||
|
||
rhs = fold (const_binop (BIT_AND_EXPR,
|
||
const_binop (LSHIFT_EXPR,
|
||
convert (unsigned_type, rhs),
|
||
size_int (lbitpos), 0),
|
||
mask, 0));
|
||
|
||
return build (code, compare_type,
|
||
build (BIT_AND_EXPR, unsigned_type, lhs, mask),
|
||
rhs);
|
||
}
|
||
|
||
/* Subroutine for fold_truthop: decode a field reference.
|
||
|
||
If EXP is a comparison reference, we return the innermost reference.
|
||
|
||
*PBITSIZE is set to the number of bits in the reference, *PBITPOS is
|
||
set to the starting bit number.
|
||
|
||
If the innermost field can be completely contained in a mode-sized
|
||
unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
|
||
|
||
*PVOLATILEP is set to 1 if the any expression encountered is volatile;
|
||
otherwise it is not changed.
|
||
|
||
*PUNSIGNEDP is set to the signedness of the field.
|
||
|
||
*PMASK is set to the mask used. This is either contained in a
|
||
BIT_AND_EXPR or derived from the width of the field.
|
||
|
||
*PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
|
||
|
||
Return 0 if this is not a component reference or is one that we can't
|
||
do anything with. */
|
||
|
||
static tree
|
||
decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
|
||
pvolatilep, pmask, pand_mask)
|
||
tree exp;
|
||
int *pbitsize, *pbitpos;
|
||
enum machine_mode *pmode;
|
||
int *punsignedp, *pvolatilep;
|
||
tree *pmask;
|
||
tree *pand_mask;
|
||
{
|
||
tree and_mask = 0;
|
||
tree mask, inner, offset;
|
||
tree unsigned_type;
|
||
int precision;
|
||
int alignment;
|
||
|
||
/* All the optimizations using this function assume integer fields.
|
||
There are problems with FP fields since the type_for_size call
|
||
below can fail for, e.g., XFmode. */
|
||
if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
|
||
return 0;
|
||
|
||
STRIP_NOPS (exp);
|
||
|
||
if (TREE_CODE (exp) == BIT_AND_EXPR)
|
||
{
|
||
and_mask = TREE_OPERAND (exp, 1);
|
||
exp = TREE_OPERAND (exp, 0);
|
||
STRIP_NOPS (exp); STRIP_NOPS (and_mask);
|
||
if (TREE_CODE (and_mask) != INTEGER_CST)
|
||
return 0;
|
||
}
|
||
|
||
|
||
inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
|
||
punsignedp, pvolatilep, &alignment);
|
||
if ((inner == exp && and_mask == 0)
|
||
|| *pbitsize < 0 || offset != 0)
|
||
return 0;
|
||
|
||
/* Compute the mask to access the bitfield. */
|
||
unsigned_type = type_for_size (*pbitsize, 1);
|
||
precision = TYPE_PRECISION (unsigned_type);
|
||
|
||
mask = build_int_2 (~0, ~0);
|
||
TREE_TYPE (mask) = unsigned_type;
|
||
force_fit_type (mask, 0);
|
||
mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
|
||
mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
|
||
|
||
/* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
|
||
if (and_mask != 0)
|
||
mask = fold (build (BIT_AND_EXPR, unsigned_type,
|
||
convert (unsigned_type, and_mask), mask));
|
||
|
||
*pmask = mask;
|
||
*pand_mask = and_mask;
|
||
return inner;
|
||
}
|
||
|
||
/* Return non-zero if MASK represents a mask of SIZE ones in the low-order
|
||
bit positions. */
|
||
|
||
static int
|
||
all_ones_mask_p (mask, size)
|
||
tree mask;
|
||
int size;
|
||
{
|
||
tree type = TREE_TYPE (mask);
|
||
int precision = TYPE_PRECISION (type);
|
||
tree tmask;
|
||
|
||
tmask = build_int_2 (~0, ~0);
|
||
TREE_TYPE (tmask) = signed_type (type);
|
||
force_fit_type (tmask, 0);
|
||
return
|
||
tree_int_cst_equal (mask,
|
||
const_binop (RSHIFT_EXPR,
|
||
const_binop (LSHIFT_EXPR, tmask,
|
||
size_int (precision - size),
|
||
0),
|
||
size_int (precision - size), 0));
|
||
}
|
||
|
||
/* Subroutine for fold_truthop: determine if an operand is simple enough
|
||
to be evaluated unconditionally. */
|
||
|
||
static int
|
||
simple_operand_p (exp)
|
||
tree exp;
|
||
{
|
||
/* Strip any conversions that don't change the machine mode. */
|
||
while ((TREE_CODE (exp) == NOP_EXPR
|
||
|| TREE_CODE (exp) == CONVERT_EXPR)
|
||
&& (TYPE_MODE (TREE_TYPE (exp))
|
||
== TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
|
||
exp = TREE_OPERAND (exp, 0);
|
||
|
||
return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
|
||
|| (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
|
||
&& ! TREE_ADDRESSABLE (exp)
|
||
&& ! TREE_THIS_VOLATILE (exp)
|
||
&& ! DECL_NONLOCAL (exp)
|
||
/* Don't regard global variables as simple. They may be
|
||
allocated in ways unknown to the compiler (shared memory,
|
||
#pragma weak, etc). */
|
||
&& ! TREE_PUBLIC (exp)
|
||
&& ! DECL_EXTERNAL (exp)
|
||
/* Loading a static variable is unduly expensive, but global
|
||
registers aren't expensive. */
|
||
&& (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
|
||
}
|
||
|
||
/* The following functions are subroutines to fold_range_test and allow it to
|
||
try to change a logical combination of comparisons into a range test.
|
||
|
||
For example, both
|
||
X == 2 && X == 3 && X == 4 && X == 5
|
||
and
|
||
X >= 2 && X <= 5
|
||
are converted to
|
||
(unsigned) (X - 2) <= 3
|
||
|
||
We describe each set of comparisons as being either inside or outside
|
||
a range, using a variable named like IN_P, and then describe the
|
||
range with a lower and upper bound. If one of the bounds is omitted,
|
||
it represents either the highest or lowest value of the type.
|
||
|
||
In the comments below, we represent a range by two numbers in brackets
|
||
preceded by a "+" to designate being inside that range, or a "-" to
|
||
designate being outside that range, so the condition can be inverted by
|
||
flipping the prefix. An omitted bound is represented by a "-". For
|
||
example, "- [-, 10]" means being outside the range starting at the lowest
|
||
possible value and ending at 10, in other words, being greater than 10.
|
||
The range "+ [-, -]" is always true and hence the range "- [-, -]" is
|
||
always false.
|
||
|
||
We set up things so that the missing bounds are handled in a consistent
|
||
manner so neither a missing bound nor "true" and "false" need to be
|
||
handled using a special case. */
|
||
|
||
/* Return the result of applying CODE to ARG0 and ARG1, but handle the case
|
||
of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
|
||
and UPPER1_P are nonzero if the respective argument is an upper bound
|
||
and zero for a lower. TYPE, if nonzero, is the type of the result; it
|
||
must be specified for a comparison. ARG1 will be converted to ARG0's
|
||
type if both are specified. */
|
||
|
||
static tree
|
||
range_binop (code, type, arg0, upper0_p, arg1, upper1_p)
|
||
enum tree_code code;
|
||
tree type;
|
||
tree arg0, arg1;
|
||
int upper0_p, upper1_p;
|
||
{
|
||
tree tem;
|
||
int result;
|
||
int sgn0, sgn1;
|
||
|
||
/* If neither arg represents infinity, do the normal operation.
|
||
Else, if not a comparison, return infinity. Else handle the special
|
||
comparison rules. Note that most of the cases below won't occur, but
|
||
are handled for consistency. */
|
||
|
||
if (arg0 != 0 && arg1 != 0)
|
||
{
|
||
tem = fold (build (code, type != 0 ? type : TREE_TYPE (arg0),
|
||
arg0, convert (TREE_TYPE (arg0), arg1)));
|
||
STRIP_NOPS (tem);
|
||
return TREE_CODE (tem) == INTEGER_CST ? tem : 0;
|
||
}
|
||
|
||
if (TREE_CODE_CLASS (code) != '<')
|
||
return 0;
|
||
|
||
/* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
|
||
for neither. In real maths, we cannot assume open ended ranges are
|
||
the same. But, this is computer arithmetic, where numbers are finite.
|
||
We can therefore make the transformation of any unbounded range with
|
||
the value Z, Z being greater than any representable number. This permits
|
||
us to treat unbounded ranges as equal. */
|
||
sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1);
|
||
sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1);
|
||
switch (code)
|
||
{
|
||
case EQ_EXPR:
|
||
result = sgn0 == sgn1;
|
||
break;
|
||
case NE_EXPR:
|
||
result = sgn0 != sgn1;
|
||
break;
|
||
case LT_EXPR:
|
||
result = sgn0 < sgn1;
|
||
break;
|
||
case LE_EXPR:
|
||
result = sgn0 <= sgn1;
|
||
break;
|
||
case GT_EXPR:
|
||
result = sgn0 > sgn1;
|
||
break;
|
||
case GE_EXPR:
|
||
result = sgn0 >= sgn1;
|
||
break;
|
||
default:
|
||
abort ();
|
||
}
|
||
|
||
return convert (type, result ? integer_one_node : integer_zero_node);
|
||
}
|
||
|
||
/* Given EXP, a logical expression, set the range it is testing into
|
||
variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
|
||
actually being tested. *PLOW and *PHIGH will have be made the same type
|
||
as the returned expression. If EXP is not a comparison, we will most
|
||
likely not be returning a useful value and range. */
|
||
|
||
static tree
|
||
make_range (exp, pin_p, plow, phigh)
|
||
tree exp;
|
||
int *pin_p;
|
||
tree *plow, *phigh;
|
||
{
|
||
enum tree_code code;
|
||
tree arg0, arg1, type = NULL_TREE;
|
||
tree orig_type = NULL_TREE;
|
||
int in_p, n_in_p;
|
||
tree low, high, n_low, n_high;
|
||
|
||
/* Start with simply saying "EXP != 0" and then look at the code of EXP
|
||
and see if we can refine the range. Some of the cases below may not
|
||
happen, but it doesn't seem worth worrying about this. We "continue"
|
||
the outer loop when we've changed something; otherwise we "break"
|
||
the switch, which will "break" the while. */
|
||
|
||
in_p = 0, low = high = convert (TREE_TYPE (exp), integer_zero_node);
|
||
|
||
while (1)
|
||
{
|
||
code = TREE_CODE (exp);
|
||
|
||
if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
|
||
{
|
||
arg0 = TREE_OPERAND (exp, 0);
|
||
if (TREE_CODE_CLASS (code) == '<'
|
||
|| TREE_CODE_CLASS (code) == '1'
|
||
|| TREE_CODE_CLASS (code) == '2')
|
||
type = TREE_TYPE (arg0);
|
||
if (TREE_CODE_CLASS (code) == '2'
|
||
|| TREE_CODE_CLASS (code) == '<'
|
||
|| (TREE_CODE_CLASS (code) == 'e'
|
||
&& tree_code_length[(int) code] > 1))
|
||
arg1 = TREE_OPERAND (exp, 1);
|
||
}
|
||
|
||
switch (code)
|
||
{
|
||
case TRUTH_NOT_EXPR:
|
||
in_p = ! in_p, exp = arg0;
|
||
continue;
|
||
|
||
case EQ_EXPR: case NE_EXPR:
|
||
case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR:
|
||
/* We can only do something if the range is testing for zero
|
||
and if the second operand is an integer constant. Note that
|
||
saying something is "in" the range we make is done by
|
||
complementing IN_P since it will set in the initial case of
|
||
being not equal to zero; "out" is leaving it alone. */
|
||
if (low == 0 || high == 0
|
||
|| ! integer_zerop (low) || ! integer_zerop (high)
|
||
|| TREE_CODE (arg1) != INTEGER_CST)
|
||
break;
|
||
|
||
switch (code)
|
||
{
|
||
case NE_EXPR: /* - [c, c] */
|
||
low = high = arg1;
|
||
break;
|
||
case EQ_EXPR: /* + [c, c] */
|
||
in_p = ! in_p, low = high = arg1;
|
||
break;
|
||
case GT_EXPR: /* - [-, c] */
|
||
low = 0, high = arg1;
|
||
break;
|
||
case GE_EXPR: /* + [c, -] */
|
||
in_p = ! in_p, low = arg1, high = 0;
|
||
break;
|
||
case LT_EXPR: /* - [c, -] */
|
||
low = arg1, high = 0;
|
||
break;
|
||
case LE_EXPR: /* + [-, c] */
|
||
in_p = ! in_p, low = 0, high = arg1;
|
||
break;
|
||
default:
|
||
abort ();
|
||
}
|
||
|
||
exp = arg0;
|
||
|
||
/* If this is an unsigned comparison, we also know that EXP is
|
||
greater than or equal to zero. We base the range tests we make
|
||
on that fact, so we record it here so we can parse existing
|
||
range tests. */
|
||
if (TREE_UNSIGNED (type) && (low == 0 || high == 0))
|
||
{
|
||
if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
|
||
1, convert (type, integer_zero_node),
|
||
NULL_TREE))
|
||
break;
|
||
|
||
in_p = n_in_p, low = n_low, high = n_high;
|
||
|
||
/* If the high bound is missing, reverse the range so it
|
||
goes from zero to the low bound minus 1. */
|
||
if (high == 0)
|
||
{
|
||
in_p = ! in_p;
|
||
high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,
|
||
integer_one_node, 0);
|
||
low = convert (type, integer_zero_node);
|
||
}
|
||
}
|
||
continue;
|
||
|
||
case NEGATE_EXPR:
|
||
/* (-x) IN [a,b] -> x in [-b, -a] */
|
||
n_low = range_binop (MINUS_EXPR, type,
|
||
convert (type, integer_zero_node), 0, high, 1);
|
||
n_high = range_binop (MINUS_EXPR, type,
|
||
convert (type, integer_zero_node), 0, low, 0);
|
||
low = n_low, high = n_high;
|
||
exp = arg0;
|
||
continue;
|
||
|
||
case BIT_NOT_EXPR:
|
||
/* ~ X -> -X - 1 */
|
||
exp = build (MINUS_EXPR, type, build1 (NEGATE_EXPR, type, arg0),
|
||
convert (type, integer_one_node));
|
||
continue;
|
||
|
||
case PLUS_EXPR: case MINUS_EXPR:
|
||
if (TREE_CODE (arg1) != INTEGER_CST)
|
||
break;
|
||
|
||
/* If EXP is signed, any overflow in the computation is undefined,
|
||
so we don't worry about it so long as our computations on
|
||
the bounds don't overflow. For unsigned, overflow is defined
|
||
and this is exactly the right thing. */
|
||
n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
|
||
type, low, 0, arg1, 0);
|
||
n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
|
||
type, high, 1, arg1, 0);
|
||
if ((n_low != 0 && TREE_OVERFLOW (n_low))
|
||
|| (n_high != 0 && TREE_OVERFLOW (n_high)))
|
||
break;
|
||
|
||
/* Check for an unsigned range which has wrapped around the maximum
|
||
value thus making n_high < n_low, and normalize it. */
|
||
if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
|
||
{
|
||
low = range_binop (PLUS_EXPR, type, n_high, 0,
|
||
integer_one_node, 0);
|
||
high = range_binop (MINUS_EXPR, type, n_low, 0,
|
||
integer_one_node, 0);
|
||
in_p = ! in_p;
|
||
}
|
||
else
|
||
low = n_low, high = n_high;
|
||
|
||
exp = arg0;
|
||
continue;
|
||
|
||
case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR:
|
||
if (orig_type == NULL_TREE)
|
||
orig_type = type;
|
||
if (TYPE_PRECISION (type) > TYPE_PRECISION (orig_type))
|
||
break;
|
||
|
||
if (! INTEGRAL_TYPE_P (type)
|
||
|| (low != 0 && ! int_fits_type_p (low, type))
|
||
|| (high != 0 && ! int_fits_type_p (high, type)))
|
||
break;
|
||
|
||
n_low = low, n_high = high;
|
||
|
||
if (n_low != 0)
|
||
n_low = convert (type, n_low);
|
||
|
||
if (n_high != 0)
|
||
n_high = convert (type, n_high);
|
||
|
||
/* If we're converting from an unsigned to a signed type,
|
||
we will be doing the comparison as unsigned. The tests above
|
||
have already verified that LOW and HIGH are both positive.
|
||
|
||
So we have to make sure that the original unsigned value will
|
||
be interpreted as positive. */
|
||
if (TREE_UNSIGNED (type) && ! TREE_UNSIGNED (TREE_TYPE (exp)))
|
||
{
|
||
tree equiv_type = type_for_mode (TYPE_MODE (type), 1);
|
||
tree high_positive;
|
||
|
||
/* A range without an upper bound is, naturally, unbounded.
|
||
Since convert would have cropped a very large value, use
|
||
the max value for the destination type. */
|
||
|
||
high_positive = TYPE_MAX_VALUE (equiv_type);
|
||
if (!high_positive)
|
||
{
|
||
high_positive = TYPE_MAX_VALUE (type);
|
||
if (!high_positive)
|
||
abort();
|
||
}
|
||
high_positive = fold (build (RSHIFT_EXPR, type,
|
||
convert (type, high_positive),
|
||
convert (type, integer_one_node)));
|
||
|
||
/* If the low bound is specified, "and" the range with the
|
||
range for which the original unsigned value will be
|
||
positive. */
|
||
if (low != 0)
|
||
{
|
||
if (! merge_ranges (&n_in_p, &n_low, &n_high,
|
||
1, n_low, n_high,
|
||
1, convert (type, integer_zero_node),
|
||
high_positive))
|
||
break;
|
||
|
||
in_p = (n_in_p == in_p);
|
||
}
|
||
else
|
||
{
|
||
/* Otherwise, "or" the range with the range of the input
|
||
that will be interpreted as negative. */
|
||
if (! merge_ranges (&n_in_p, &n_low, &n_high,
|
||
0, n_low, n_high,
|
||
1, convert (type, integer_zero_node),
|
||
high_positive))
|
||
break;
|
||
|
||
in_p = (in_p != n_in_p);
|
||
}
|
||
}
|
||
|
||
exp = arg0;
|
||
low = n_low, high = n_high;
|
||
continue;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
break;
|
||
}
|
||
|
||
/* If EXP is a constant, we can evaluate whether this is true or false. */
|
||
if (TREE_CODE (exp) == INTEGER_CST)
|
||
{
|
||
in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node,
|
||
exp, 0, low, 0))
|
||
&& integer_onep (range_binop (LE_EXPR, integer_type_node,
|
||
exp, 1, high, 1)));
|
||
low = high = 0;
|
||
exp = 0;
|
||
}
|
||
|
||
*pin_p = in_p, *plow = low, *phigh = high;
|
||
return exp;
|
||
}
|
||
|
||
/* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
|
||
type, TYPE, return an expression to test if EXP is in (or out of, depending
|
||
on IN_P) the range. */
|
||
|
||
static tree
|
||
build_range_check (type, exp, in_p, low, high)
|
||
tree type;
|
||
tree exp;
|
||
int in_p;
|
||
tree low, high;
|
||
{
|
||
tree etype = TREE_TYPE (exp);
|
||
tree utype, value;
|
||
|
||
if (! in_p
|
||
&& (0 != (value = build_range_check (type, exp, 1, low, high))))
|
||
return invert_truthvalue (value);
|
||
|
||
else if (low == 0 && high == 0)
|
||
return convert (type, integer_one_node);
|
||
|
||
else if (low == 0)
|
||
return fold (build (LE_EXPR, type, exp, high));
|
||
|
||
else if (high == 0)
|
||
return fold (build (GE_EXPR, type, exp, low));
|
||
|
||
else if (operand_equal_p (low, high, 0))
|
||
return fold (build (EQ_EXPR, type, exp, low));
|
||
|
||
else if (TREE_UNSIGNED (etype) && integer_zerop (low))
|
||
return build_range_check (type, exp, 1, 0, high);
|
||
|
||
else if (integer_zerop (low))
|
||
{
|
||
utype = unsigned_type (etype);
|
||
return build_range_check (type, convert (utype, exp), 1, 0,
|
||
convert (utype, high));
|
||
}
|
||
|
||
else if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
|
||
&& ! TREE_OVERFLOW (value))
|
||
return build_range_check (type,
|
||
fold (build (MINUS_EXPR, etype, exp, low)),
|
||
1, convert (etype, integer_zero_node), value);
|
||
else
|
||
return 0;
|
||
}
|
||
|
||
/* Given two ranges, see if we can merge them into one. Return 1 if we
|
||
can, 0 if we can't. Set the output range into the specified parameters. */
|
||
|
||
static int
|
||
merge_ranges (pin_p, plow, phigh, in0_p, low0, high0, in1_p, low1, high1)
|
||
int *pin_p;
|
||
tree *plow, *phigh;
|
||
int in0_p, in1_p;
|
||
tree low0, high0, low1, high1;
|
||
{
|
||
int no_overlap;
|
||
int subset;
|
||
int temp;
|
||
tree tem;
|
||
int in_p;
|
||
tree low, high;
|
||
int lowequal = ((low0 == 0 && low1 == 0)
|
||
|| integer_onep (range_binop (EQ_EXPR, integer_type_node,
|
||
low0, 0, low1, 0)));
|
||
int highequal = ((high0 == 0 && high1 == 0)
|
||
|| integer_onep (range_binop (EQ_EXPR, integer_type_node,
|
||
high0, 1, high1, 1)));
|
||
|
||
/* Make range 0 be the range that starts first, or ends last if they
|
||
start at the same value. Swap them if it isn't. */
|
||
if (integer_onep (range_binop (GT_EXPR, integer_type_node,
|
||
low0, 0, low1, 0))
|
||
|| (lowequal
|
||
&& integer_onep (range_binop (GT_EXPR, integer_type_node,
|
||
high1, 1, high0, 1))))
|
||
{
|
||
temp = in0_p, in0_p = in1_p, in1_p = temp;
|
||
tem = low0, low0 = low1, low1 = tem;
|
||
tem = high0, high0 = high1, high1 = tem;
|
||
}
|
||
|
||
/* Now flag two cases, whether the ranges are disjoint or whether the
|
||
second range is totally subsumed in the first. Note that the tests
|
||
below are simplified by the ones above. */
|
||
no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node,
|
||
high0, 1, low1, 0));
|
||
subset = integer_onep (range_binop (LE_EXPR, integer_type_node,
|
||
high1, 1, high0, 1));
|
||
|
||
/* We now have four cases, depending on whether we are including or
|
||
excluding the two ranges. */
|
||
if (in0_p && in1_p)
|
||
{
|
||
/* If they don't overlap, the result is false. If the second range
|
||
is a subset it is the result. Otherwise, the range is from the start
|
||
of the second to the end of the first. */
|
||
if (no_overlap)
|
||
in_p = 0, low = high = 0;
|
||
else if (subset)
|
||
in_p = 1, low = low1, high = high1;
|
||
else
|
||
in_p = 1, low = low1, high = high0;
|
||
}
|
||
|
||
else if (in0_p && ! in1_p)
|
||
{
|
||
/* If they don't overlap, the result is the first range. If they are
|
||
equal, the result is false. If the second range is a subset of the
|
||
first, and the ranges begin at the same place, we go from just after
|
||
the end of the first range to the end of the second. If the second
|
||
range is not a subset of the first, or if it is a subset and both
|
||
ranges end at the same place, the range starts at the start of the
|
||
first range and ends just before the second range.
|
||
Otherwise, we can't describe this as a single range. */
|
||
if (no_overlap)
|
||
in_p = 1, low = low0, high = high0;
|
||
else if (lowequal && highequal)
|
||
in_p = 0, low = high = 0;
|
||
else if (subset && lowequal)
|
||
{
|
||
in_p = 1, high = high0;
|
||
low = range_binop (PLUS_EXPR, NULL_TREE, high1, 0,
|
||
integer_one_node, 0);
|
||
}
|
||
else if (! subset || highequal)
|
||
{
|
||
in_p = 1, low = low0;
|
||
high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0,
|
||
integer_one_node, 0);
|
||
}
|
||
else
|
||
return 0;
|
||
}
|
||
|
||
else if (! in0_p && in1_p)
|
||
{
|
||
/* If they don't overlap, the result is the second range. If the second
|
||
is a subset of the first, the result is false. Otherwise,
|
||
the range starts just after the first range and ends at the
|
||
end of the second. */
|
||
if (no_overlap)
|
||
in_p = 1, low = low1, high = high1;
|
||
else if (subset)
|
||
in_p = 0, low = high = 0;
|
||
else
|
||
{
|
||
in_p = 1, high = high1;
|
||
low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1,
|
||
integer_one_node, 0);
|
||
}
|
||
}
|
||
|
||
else
|
||
{
|
||
/* The case where we are excluding both ranges. Here the complex case
|
||
is if they don't overlap. In that case, the only time we have a
|
||
range is if they are adjacent. If the second is a subset of the
|
||
first, the result is the first. Otherwise, the range to exclude
|
||
starts at the beginning of the first range and ends at the end of the
|
||
second. */
|
||
if (no_overlap)
|
||
{
|
||
if (integer_onep (range_binop (EQ_EXPR, integer_type_node,
|
||
range_binop (PLUS_EXPR, NULL_TREE,
|
||
high0, 1,
|
||
integer_one_node, 1),
|
||
1, low1, 0)))
|
||
in_p = 0, low = low0, high = high1;
|
||
else
|
||
return 0;
|
||
}
|
||
else if (subset)
|
||
in_p = 0, low = low0, high = high0;
|
||
else
|
||
in_p = 0, low = low0, high = high1;
|
||
}
|
||
|
||
*pin_p = in_p, *plow = low, *phigh = high;
|
||
return 1;
|
||
}
|
||
|
||
/* EXP is some logical combination of boolean tests. See if we can
|
||
merge it into some range test. Return the new tree if so. */
|
||
|
||
static tree
|
||
fold_range_test (exp)
|
||
tree exp;
|
||
{
|
||
int or_op = (TREE_CODE (exp) == TRUTH_ORIF_EXPR
|
||
|| TREE_CODE (exp) == TRUTH_OR_EXPR);
|
||
int in0_p, in1_p, in_p;
|
||
tree low0, low1, low, high0, high1, high;
|
||
tree lhs = make_range (TREE_OPERAND (exp, 0), &in0_p, &low0, &high0);
|
||
tree rhs = make_range (TREE_OPERAND (exp, 1), &in1_p, &low1, &high1);
|
||
tree tem;
|
||
|
||
/* If this is an OR operation, invert both sides; we will invert
|
||
again at the end. */
|
||
if (or_op)
|
||
in0_p = ! in0_p, in1_p = ! in1_p;
|
||
|
||
/* If both expressions are the same, if we can merge the ranges, and we
|
||
can build the range test, return it or it inverted. If one of the
|
||
ranges is always true or always false, consider it to be the same
|
||
expression as the other. */
|
||
if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0))
|
||
&& merge_ranges (&in_p, &low, &high, in0_p, low0, high0,
|
||
in1_p, low1, high1)
|
||
&& 0 != (tem = (build_range_check (TREE_TYPE (exp),
|
||
lhs != 0 ? lhs
|
||
: rhs != 0 ? rhs : integer_zero_node,
|
||
in_p, low, high))))
|
||
return or_op ? invert_truthvalue (tem) : tem;
|
||
|
||
/* On machines where the branch cost is expensive, if this is a
|
||
short-circuited branch and the underlying object on both sides
|
||
is the same, make a non-short-circuit operation. */
|
||
else if (BRANCH_COST >= 2
|
||
&& (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
|
||
|| TREE_CODE (exp) == TRUTH_ORIF_EXPR)
|
||
&& operand_equal_p (lhs, rhs, 0))
|
||
{
|
||
/* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
|
||
unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
|
||
which cases we can't do this. */
|
||
if (simple_operand_p (lhs))
|
||
return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
|
||
? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
|
||
TREE_TYPE (exp), TREE_OPERAND (exp, 0),
|
||
TREE_OPERAND (exp, 1));
|
||
|
||
else if (current_function_decl != 0
|
||
&& ! contains_placeholder_p (lhs))
|
||
{
|
||
tree common = save_expr (lhs);
|
||
|
||
if (0 != (lhs = build_range_check (TREE_TYPE (exp), common,
|
||
or_op ? ! in0_p : in0_p,
|
||
low0, high0))
|
||
&& (0 != (rhs = build_range_check (TREE_TYPE (exp), common,
|
||
or_op ? ! in1_p : in1_p,
|
||
low1, high1))))
|
||
return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
|
||
? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
|
||
TREE_TYPE (exp), lhs, rhs);
|
||
}
|
||
}
|
||
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
|
||
bit value. Arrange things so the extra bits will be set to zero if and
|
||
only if C is signed-extended to its full width. If MASK is nonzero,
|
||
it is an INTEGER_CST that should be AND'ed with the extra bits. */
|
||
|
||
static tree
|
||
unextend (c, p, unsignedp, mask)
|
||
tree c;
|
||
int p;
|
||
int unsignedp;
|
||
tree mask;
|
||
{
|
||
tree type = TREE_TYPE (c);
|
||
int modesize = GET_MODE_BITSIZE (TYPE_MODE (type));
|
||
tree temp;
|
||
|
||
if (p == modesize || unsignedp)
|
||
return c;
|
||
|
||
/* We work by getting just the sign bit into the low-order bit, then
|
||
into the high-order bit, then sign-extend. We then XOR that value
|
||
with C. */
|
||
temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0);
|
||
temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0);
|
||
|
||
/* We must use a signed type in order to get an arithmetic right shift.
|
||
However, we must also avoid introducing accidental overflows, so that
|
||
a subsequent call to integer_zerop will work. Hence we must
|
||
do the type conversion here. At this point, the constant is either
|
||
zero or one, and the conversion to a signed type can never overflow.
|
||
We could get an overflow if this conversion is done anywhere else. */
|
||
if (TREE_UNSIGNED (type))
|
||
temp = convert (signed_type (type), temp);
|
||
|
||
temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0);
|
||
temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0);
|
||
if (mask != 0)
|
||
temp = const_binop (BIT_AND_EXPR, temp, convert (TREE_TYPE (c), mask), 0);
|
||
/* If necessary, convert the type back to match the type of C. */
|
||
if (TREE_UNSIGNED (type))
|
||
temp = convert (type, temp);
|
||
|
||
return convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0));
|
||
}
|
||
|
||
/* Find ways of folding logical expressions of LHS and RHS:
|
||
Try to merge two comparisons to the same innermost item.
|
||
Look for range tests like "ch >= '0' && ch <= '9'".
|
||
Look for combinations of simple terms on machines with expensive branches
|
||
and evaluate the RHS unconditionally.
|
||
|
||
For example, if we have p->a == 2 && p->b == 4 and we can make an
|
||
object large enough to span both A and B, we can do this with a comparison
|
||
against the object ANDed with the a mask.
|
||
|
||
If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
|
||
operations to do this with one comparison.
|
||
|
||
We check for both normal comparisons and the BIT_AND_EXPRs made this by
|
||
function and the one above.
|
||
|
||
CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
|
||
TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
|
||
|
||
TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
|
||
two operands.
|
||
|
||
We return the simplified tree or 0 if no optimization is possible. */
|
||
|
||
static tree
|
||
fold_truthop (code, truth_type, lhs, rhs)
|
||
enum tree_code code;
|
||
tree truth_type, lhs, rhs;
|
||
{
|
||
/* If this is the "or" of two comparisons, we can do something if we
|
||
the comparisons are NE_EXPR. If this is the "and", we can do something
|
||
if the comparisons are EQ_EXPR. I.e.,
|
||
(a->b == 2 && a->c == 4) can become (a->new == NEW).
|
||
|
||
WANTED_CODE is this operation code. For single bit fields, we can
|
||
convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
|
||
comparison for one-bit fields. */
|
||
|
||
enum tree_code wanted_code;
|
||
enum tree_code lcode, rcode;
|
||
tree ll_arg, lr_arg, rl_arg, rr_arg;
|
||
tree ll_inner, lr_inner, rl_inner, rr_inner;
|
||
int ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos;
|
||
int rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos;
|
||
int xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos;
|
||
int lnbitsize, lnbitpos, rnbitsize, rnbitpos;
|
||
int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp;
|
||
enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
|
||
enum machine_mode lnmode, rnmode;
|
||
tree ll_mask, lr_mask, rl_mask, rr_mask;
|
||
tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask;
|
||
tree l_const, r_const;
|
||
tree type, result;
|
||
int first_bit, end_bit;
|
||
int volatilep;
|
||
|
||
/* Start by getting the comparison codes. Fail if anything is volatile.
|
||
If one operand is a BIT_AND_EXPR with the constant one, treat it as if
|
||
it were surrounded with a NE_EXPR. */
|
||
|
||
if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs))
|
||
return 0;
|
||
|
||
lcode = TREE_CODE (lhs);
|
||
rcode = TREE_CODE (rhs);
|
||
|
||
if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1)))
|
||
lcode = NE_EXPR, lhs = build (NE_EXPR, truth_type, lhs, integer_zero_node);
|
||
|
||
if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1)))
|
||
rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node);
|
||
|
||
if (TREE_CODE_CLASS (lcode) != '<' || TREE_CODE_CLASS (rcode) != '<')
|
||
return 0;
|
||
|
||
code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
|
||
? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
|
||
|
||
ll_arg = TREE_OPERAND (lhs, 0);
|
||
lr_arg = TREE_OPERAND (lhs, 1);
|
||
rl_arg = TREE_OPERAND (rhs, 0);
|
||
rr_arg = TREE_OPERAND (rhs, 1);
|
||
|
||
/* If the RHS can be evaluated unconditionally and its operands are
|
||
simple, it wins to evaluate the RHS unconditionally on machines
|
||
with expensive branches. In this case, this isn't a comparison
|
||
that can be merged. */
|
||
|
||
/* @@ I'm not sure it wins on the m88110 to do this if the comparisons
|
||
are with zero (tmw). */
|
||
|
||
if (BRANCH_COST >= 2
|
||
&& INTEGRAL_TYPE_P (TREE_TYPE (rhs))
|
||
&& simple_operand_p (rl_arg)
|
||
&& simple_operand_p (rr_arg))
|
||
return build (code, truth_type, lhs, rhs);
|
||
|
||
/* See if the comparisons can be merged. Then get all the parameters for
|
||
each side. */
|
||
|
||
if ((lcode != EQ_EXPR && lcode != NE_EXPR)
|
||
|| (rcode != EQ_EXPR && rcode != NE_EXPR))
|
||
return 0;
|
||
|
||
volatilep = 0;
|
||
ll_inner = decode_field_reference (ll_arg,
|
||
&ll_bitsize, &ll_bitpos, &ll_mode,
|
||
&ll_unsignedp, &volatilep, &ll_mask,
|
||
&ll_and_mask);
|
||
lr_inner = decode_field_reference (lr_arg,
|
||
&lr_bitsize, &lr_bitpos, &lr_mode,
|
||
&lr_unsignedp, &volatilep, &lr_mask,
|
||
&lr_and_mask);
|
||
rl_inner = decode_field_reference (rl_arg,
|
||
&rl_bitsize, &rl_bitpos, &rl_mode,
|
||
&rl_unsignedp, &volatilep, &rl_mask,
|
||
&rl_and_mask);
|
||
rr_inner = decode_field_reference (rr_arg,
|
||
&rr_bitsize, &rr_bitpos, &rr_mode,
|
||
&rr_unsignedp, &volatilep, &rr_mask,
|
||
&rr_and_mask);
|
||
|
||
/* It must be true that the inner operation on the lhs of each
|
||
comparison must be the same if we are to be able to do anything.
|
||
Then see if we have constants. If not, the same must be true for
|
||
the rhs's. */
|
||
if (volatilep || ll_inner == 0 || rl_inner == 0
|
||
|| ! operand_equal_p (ll_inner, rl_inner, 0))
|
||
return 0;
|
||
|
||
if (TREE_CODE (lr_arg) == INTEGER_CST
|
||
&& TREE_CODE (rr_arg) == INTEGER_CST)
|
||
l_const = lr_arg, r_const = rr_arg;
|
||
else if (lr_inner == 0 || rr_inner == 0
|
||
|| ! operand_equal_p (lr_inner, rr_inner, 0))
|
||
return 0;
|
||
else
|
||
l_const = r_const = 0;
|
||
|
||
/* If either comparison code is not correct for our logical operation,
|
||
fail. However, we can convert a one-bit comparison against zero into
|
||
the opposite comparison against that bit being set in the field. */
|
||
|
||
wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
|
||
if (lcode != wanted_code)
|
||
{
|
||
if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
|
||
{
|
||
if (ll_unsignedp || tree_log2 (ll_mask) + 1 < ll_bitsize)
|
||
l_const = ll_mask;
|
||
else
|
||
/* Since ll_arg is a single bit bit mask, we can sign extend
|
||
it appropriately with a NEGATE_EXPR.
|
||
l_const is made a signed value here, but since for l_const != NULL
|
||
lr_unsignedp is not used, we don't need to clear the latter. */
|
||
l_const = fold (build1 (NEGATE_EXPR, TREE_TYPE (ll_arg),
|
||
convert (TREE_TYPE (ll_arg), ll_mask)));
|
||
}
|
||
else
|
||
return 0;
|
||
}
|
||
|
||
if (rcode != wanted_code)
|
||
{
|
||
if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
|
||
{
|
||
if (rl_unsignedp || tree_log2 (rl_mask) + 1 < rl_bitsize)
|
||
r_const = rl_mask;
|
||
else
|
||
/* This is analogous to the code for l_const above. */
|
||
r_const = fold (build1 (NEGATE_EXPR, TREE_TYPE (rl_arg),
|
||
convert (TREE_TYPE (rl_arg), rl_mask)));
|
||
}
|
||
else
|
||
return 0;
|
||
}
|
||
|
||
/* See if we can find a mode that contains both fields being compared on
|
||
the left. If we can't, fail. Otherwise, update all constants and masks
|
||
to be relative to a field of that size. */
|
||
first_bit = MIN (ll_bitpos, rl_bitpos);
|
||
end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
|
||
lnmode = get_best_mode (end_bit - first_bit, first_bit,
|
||
TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
|
||
volatilep);
|
||
if (lnmode == VOIDmode)
|
||
return 0;
|
||
|
||
lnbitsize = GET_MODE_BITSIZE (lnmode);
|
||
lnbitpos = first_bit & ~ (lnbitsize - 1);
|
||
type = type_for_size (lnbitsize, 1);
|
||
xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos;
|
||
|
||
if (BYTES_BIG_ENDIAN)
|
||
{
|
||
xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize;
|
||
xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize;
|
||
}
|
||
|
||
ll_mask = const_binop (LSHIFT_EXPR, convert (type, ll_mask),
|
||
size_int (xll_bitpos), 0);
|
||
rl_mask = const_binop (LSHIFT_EXPR, convert (type, rl_mask),
|
||
size_int (xrl_bitpos), 0);
|
||
|
||
if (l_const)
|
||
{
|
||
l_const = convert (type, l_const);
|
||
l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask);
|
||
l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0);
|
||
if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const,
|
||
fold (build1 (BIT_NOT_EXPR,
|
||
type, ll_mask)),
|
||
0)))
|
||
{
|
||
warning ("comparison is always %s",
|
||
wanted_code == NE_EXPR ? "one" : "zero");
|
||
|
||
return convert (truth_type,
|
||
wanted_code == NE_EXPR
|
||
? integer_one_node : integer_zero_node);
|
||
}
|
||
}
|
||
if (r_const)
|
||
{
|
||
r_const = convert (type, r_const);
|
||
r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask);
|
||
r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0);
|
||
if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const,
|
||
fold (build1 (BIT_NOT_EXPR,
|
||
type, rl_mask)),
|
||
0)))
|
||
{
|
||
warning ("comparison is always %s",
|
||
wanted_code == NE_EXPR ? "one" : "zero");
|
||
|
||
return convert (truth_type,
|
||
wanted_code == NE_EXPR
|
||
? integer_one_node : integer_zero_node);
|
||
}
|
||
}
|
||
|
||
/* If the right sides are not constant, do the same for it. Also,
|
||
disallow this optimization if a size or signedness mismatch occurs
|
||
between the left and right sides. */
|
||
if (l_const == 0)
|
||
{
|
||
if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize
|
||
|| ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp
|
||
/* Make sure the two fields on the right
|
||
correspond to the left without being swapped. */
|
||
|| ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos)
|
||
return 0;
|
||
|
||
first_bit = MIN (lr_bitpos, rr_bitpos);
|
||
end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
|
||
rnmode = get_best_mode (end_bit - first_bit, first_bit,
|
||
TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
|
||
volatilep);
|
||
if (rnmode == VOIDmode)
|
||
return 0;
|
||
|
||
rnbitsize = GET_MODE_BITSIZE (rnmode);
|
||
rnbitpos = first_bit & ~ (rnbitsize - 1);
|
||
xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos;
|
||
|
||
if (BYTES_BIG_ENDIAN)
|
||
{
|
||
xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize;
|
||
xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize;
|
||
}
|
||
|
||
lr_mask = const_binop (LSHIFT_EXPR, convert (type, lr_mask),
|
||
size_int (xlr_bitpos), 0);
|
||
rr_mask = const_binop (LSHIFT_EXPR, convert (type, rr_mask),
|
||
size_int (xrr_bitpos), 0);
|
||
|
||
/* Make a mask that corresponds to both fields being compared.
|
||
Do this for both items being compared. If the masks agree,
|
||
we can do this by masking both and comparing the masked
|
||
results. */
|
||
ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
|
||
lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0);
|
||
if (operand_equal_p (ll_mask, lr_mask, 0) && lnbitsize == rnbitsize)
|
||
{
|
||
lhs = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
|
||
ll_unsignedp || rl_unsignedp);
|
||
rhs = make_bit_field_ref (lr_inner, type, rnbitsize, rnbitpos,
|
||
lr_unsignedp || rr_unsignedp);
|
||
if (! all_ones_mask_p (ll_mask, lnbitsize))
|
||
{
|
||
lhs = build (BIT_AND_EXPR, type, lhs, ll_mask);
|
||
rhs = build (BIT_AND_EXPR, type, rhs, ll_mask);
|
||
}
|
||
return build (wanted_code, truth_type, lhs, rhs);
|
||
}
|
||
|
||
/* There is still another way we can do something: If both pairs of
|
||
fields being compared are adjacent, we may be able to make a wider
|
||
field containing them both. */
|
||
if ((ll_bitsize + ll_bitpos == rl_bitpos
|
||
&& lr_bitsize + lr_bitpos == rr_bitpos)
|
||
|| (ll_bitpos == rl_bitpos + rl_bitsize
|
||
&& lr_bitpos == rr_bitpos + rr_bitsize))
|
||
return build (wanted_code, truth_type,
|
||
make_bit_field_ref (ll_inner, type,
|
||
ll_bitsize + rl_bitsize,
|
||
MIN (ll_bitpos, rl_bitpos),
|
||
ll_unsignedp),
|
||
make_bit_field_ref (lr_inner, type,
|
||
lr_bitsize + rr_bitsize,
|
||
MIN (lr_bitpos, rr_bitpos),
|
||
lr_unsignedp));
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Handle the case of comparisons with constants. If there is something in
|
||
common between the masks, those bits of the constants must be the same.
|
||
If not, the condition is always false. Test for this to avoid generating
|
||
incorrect code below. */
|
||
result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0);
|
||
if (! integer_zerop (result)
|
||
&& simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0),
|
||
const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1)
|
||
{
|
||
if (wanted_code == NE_EXPR)
|
||
{
|
||
warning ("`or' of unmatched not-equal tests is always 1");
|
||
return convert (truth_type, integer_one_node);
|
||
}
|
||
else
|
||
{
|
||
warning ("`and' of mutually exclusive equal-tests is always zero");
|
||
return convert (truth_type, integer_zero_node);
|
||
}
|
||
}
|
||
|
||
/* Construct the expression we will return. First get the component
|
||
reference we will make. Unless the mask is all ones the width of
|
||
that field, perform the mask operation. Then compare with the
|
||
merged constant. */
|
||
result = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
|
||
ll_unsignedp || rl_unsignedp);
|
||
|
||
ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
|
||
if (! all_ones_mask_p (ll_mask, lnbitsize))
|
||
result = build (BIT_AND_EXPR, type, result, ll_mask);
|
||
|
||
return build (wanted_code, truth_type, result,
|
||
const_binop (BIT_IOR_EXPR, l_const, r_const, 0));
|
||
}
|
||
|
||
/* If T contains a COMPOUND_EXPR which was inserted merely to evaluate
|
||
S, a SAVE_EXPR, return the expression actually being evaluated. Note
|
||
that we may sometimes modify the tree. */
|
||
|
||
static tree
|
||
strip_compound_expr (t, s)
|
||
tree t;
|
||
tree s;
|
||
{
|
||
enum tree_code code = TREE_CODE (t);
|
||
|
||
/* See if this is the COMPOUND_EXPR we want to eliminate. */
|
||
if (code == COMPOUND_EXPR && TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR
|
||
&& TREE_OPERAND (TREE_OPERAND (t, 0), 0) == s)
|
||
return TREE_OPERAND (t, 1);
|
||
|
||
/* See if this is a COND_EXPR or a simple arithmetic operator. We
|
||
don't bother handling any other types. */
|
||
else if (code == COND_EXPR)
|
||
{
|
||
TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
|
||
TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
|
||
TREE_OPERAND (t, 2) = strip_compound_expr (TREE_OPERAND (t, 2), s);
|
||
}
|
||
else if (TREE_CODE_CLASS (code) == '1')
|
||
TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
|
||
else if (TREE_CODE_CLASS (code) == '<'
|
||
|| TREE_CODE_CLASS (code) == '2')
|
||
{
|
||
TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
|
||
TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
|
||
}
|
||
|
||
return t;
|
||
}
|
||
|
||
/* Return a node which has the indicated constant VALUE (either 0 or
|
||
1), and is of the indicated TYPE. */
|
||
|
||
static tree
|
||
constant_boolean_node (value, type)
|
||
int value;
|
||
tree type;
|
||
{
|
||
if (type == integer_type_node)
|
||
return value ? integer_one_node : integer_zero_node;
|
||
else if (TREE_CODE (type) == BOOLEAN_TYPE)
|
||
return truthvalue_conversion (value ? integer_one_node :
|
||
integer_zero_node);
|
||
else
|
||
{
|
||
tree t = build_int_2 (value, 0);
|
||
TREE_TYPE (t) = type;
|
||
return t;
|
||
}
|
||
}
|
||
|
||
/* Perform constant folding and related simplification of EXPR.
|
||
The related simplifications include x*1 => x, x*0 => 0, etc.,
|
||
and application of the associative law.
|
||
NOP_EXPR conversions may be removed freely (as long as we
|
||
are careful not to change the C type of the overall expression)
|
||
We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
|
||
but we can constant-fold them if they have constant operands. */
|
||
|
||
tree
|
||
fold (expr)
|
||
tree expr;
|
||
{
|
||
register tree t = expr;
|
||
tree t1 = NULL_TREE;
|
||
tree tem;
|
||
tree type = TREE_TYPE (expr);
|
||
register tree arg0 = NULL_TREE, arg1 = NULL_TREE;
|
||
register enum tree_code code = TREE_CODE (t);
|
||
register int kind;
|
||
int invert;
|
||
|
||
/* WINS will be nonzero when the switch is done
|
||
if all operands are constant. */
|
||
|
||
int wins = 1;
|
||
|
||
/* Don't try to process an RTL_EXPR since its operands aren't trees.
|
||
Likewise for a SAVE_EXPR that's already been evaluated. */
|
||
if (code == RTL_EXPR || (code == SAVE_EXPR && SAVE_EXPR_RTL (t)) != 0)
|
||
return t;
|
||
|
||
/* Return right away if already constant. */
|
||
if (TREE_CONSTANT (t))
|
||
{
|
||
if (code == CONST_DECL)
|
||
return DECL_INITIAL (t);
|
||
return t;
|
||
}
|
||
|
||
#ifdef MAX_INTEGER_COMPUTATION_MODE
|
||
check_max_integer_computation_mode (expr);
|
||
#endif
|
||
|
||
kind = TREE_CODE_CLASS (code);
|
||
if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
|
||
{
|
||
tree subop;
|
||
|
||
/* Special case for conversion ops that can have fixed point args. */
|
||
arg0 = TREE_OPERAND (t, 0);
|
||
|
||
/* Don't use STRIP_NOPS, because signedness of argument type matters. */
|
||
if (arg0 != 0)
|
||
STRIP_TYPE_NOPS (arg0);
|
||
|
||
if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST)
|
||
subop = TREE_REALPART (arg0);
|
||
else
|
||
subop = arg0;
|
||
|
||
if (subop != 0 && TREE_CODE (subop) != INTEGER_CST
|
||
#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
|
||
&& TREE_CODE (subop) != REAL_CST
|
||
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
|
||
)
|
||
/* Note that TREE_CONSTANT isn't enough:
|
||
static var addresses are constant but we can't
|
||
do arithmetic on them. */
|
||
wins = 0;
|
||
}
|
||
else if (kind == 'e' || kind == '<'
|
||
|| kind == '1' || kind == '2' || kind == 'r')
|
||
{
|
||
register int len = tree_code_length[(int) code];
|
||
register int i;
|
||
for (i = 0; i < len; i++)
|
||
{
|
||
tree op = TREE_OPERAND (t, i);
|
||
tree subop;
|
||
|
||
if (op == 0)
|
||
continue; /* Valid for CALL_EXPR, at least. */
|
||
|
||
if (kind == '<' || code == RSHIFT_EXPR)
|
||
{
|
||
/* Signedness matters here. Perhaps we can refine this
|
||
later. */
|
||
STRIP_TYPE_NOPS (op);
|
||
}
|
||
else
|
||
{
|
||
/* Strip any conversions that don't change the mode. */
|
||
STRIP_NOPS (op);
|
||
}
|
||
|
||
if (TREE_CODE (op) == COMPLEX_CST)
|
||
subop = TREE_REALPART (op);
|
||
else
|
||
subop = op;
|
||
|
||
if (TREE_CODE (subop) != INTEGER_CST
|
||
#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
|
||
&& TREE_CODE (subop) != REAL_CST
|
||
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
|
||
)
|
||
/* Note that TREE_CONSTANT isn't enough:
|
||
static var addresses are constant but we can't
|
||
do arithmetic on them. */
|
||
wins = 0;
|
||
|
||
if (i == 0)
|
||
arg0 = op;
|
||
else if (i == 1)
|
||
arg1 = op;
|
||
}
|
||
}
|
||
|
||
/* If this is a commutative operation, and ARG0 is a constant, move it
|
||
to ARG1 to reduce the number of tests below. */
|
||
if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR
|
||
|| code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR
|
||
|| code == BIT_AND_EXPR)
|
||
&& (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST))
|
||
{
|
||
tem = arg0; arg0 = arg1; arg1 = tem;
|
||
|
||
tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1);
|
||
TREE_OPERAND (t, 1) = tem;
|
||
}
|
||
|
||
/* Now WINS is set as described above,
|
||
ARG0 is the first operand of EXPR,
|
||
and ARG1 is the second operand (if it has more than one operand).
|
||
|
||
First check for cases where an arithmetic operation is applied to a
|
||
compound, conditional, or comparison operation. Push the arithmetic
|
||
operation inside the compound or conditional to see if any folding
|
||
can then be done. Convert comparison to conditional for this purpose.
|
||
The also optimizes non-constant cases that used to be done in
|
||
expand_expr.
|
||
|
||
Before we do that, see if this is a BIT_AND_EXPR or a BIT_OR_EXPR,
|
||
one of the operands is a comparison and the other is a comparison, a
|
||
BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
|
||
code below would make the expression more complex. Change it to a
|
||
TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
|
||
TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
|
||
|
||
if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR
|
||
|| code == EQ_EXPR || code == NE_EXPR)
|
||
&& ((truth_value_p (TREE_CODE (arg0))
|
||
&& (truth_value_p (TREE_CODE (arg1))
|
||
|| (TREE_CODE (arg1) == BIT_AND_EXPR
|
||
&& integer_onep (TREE_OPERAND (arg1, 1)))))
|
||
|| (truth_value_p (TREE_CODE (arg1))
|
||
&& (truth_value_p (TREE_CODE (arg0))
|
||
|| (TREE_CODE (arg0) == BIT_AND_EXPR
|
||
&& integer_onep (TREE_OPERAND (arg0, 1)))))))
|
||
{
|
||
t = fold (build (code == BIT_AND_EXPR ? TRUTH_AND_EXPR
|
||
: code == BIT_IOR_EXPR ? TRUTH_OR_EXPR
|
||
: TRUTH_XOR_EXPR,
|
||
type, arg0, arg1));
|
||
|
||
if (code == EQ_EXPR)
|
||
t = invert_truthvalue (t);
|
||
|
||
return t;
|
||
}
|
||
|
||
if (TREE_CODE_CLASS (code) == '1')
|
||
{
|
||
if (TREE_CODE (arg0) == COMPOUND_EXPR)
|
||
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
|
||
fold (build1 (code, type, TREE_OPERAND (arg0, 1))));
|
||
else if (TREE_CODE (arg0) == COND_EXPR)
|
||
{
|
||
t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0),
|
||
fold (build1 (code, type, TREE_OPERAND (arg0, 1))),
|
||
fold (build1 (code, type, TREE_OPERAND (arg0, 2)))));
|
||
|
||
/* If this was a conversion, and all we did was to move into
|
||
inside the COND_EXPR, bring it back out. But leave it if
|
||
it is a conversion from integer to integer and the
|
||
result precision is no wider than a word since such a
|
||
conversion is cheap and may be optimized away by combine,
|
||
while it couldn't if it were outside the COND_EXPR. Then return
|
||
so we don't get into an infinite recursion loop taking the
|
||
conversion out and then back in. */
|
||
|
||
if ((code == NOP_EXPR || code == CONVERT_EXPR
|
||
|| code == NON_LVALUE_EXPR)
|
||
&& TREE_CODE (t) == COND_EXPR
|
||
&& TREE_CODE (TREE_OPERAND (t, 1)) == code
|
||
&& TREE_CODE (TREE_OPERAND (t, 2)) == code
|
||
&& (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))
|
||
== TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0)))
|
||
&& ! (INTEGRAL_TYPE_P (TREE_TYPE (t))
|
||
&& INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)))
|
||
&& TYPE_PRECISION (TREE_TYPE (t)) <= BITS_PER_WORD))
|
||
t = build1 (code, type,
|
||
build (COND_EXPR,
|
||
TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)),
|
||
TREE_OPERAND (t, 0),
|
||
TREE_OPERAND (TREE_OPERAND (t, 1), 0),
|
||
TREE_OPERAND (TREE_OPERAND (t, 2), 0)));
|
||
return t;
|
||
}
|
||
else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
|
||
return fold (build (COND_EXPR, type, arg0,
|
||
fold (build1 (code, type, integer_one_node)),
|
||
fold (build1 (code, type, integer_zero_node))));
|
||
}
|
||
else if (TREE_CODE_CLASS (code) == '2'
|
||
|| TREE_CODE_CLASS (code) == '<')
|
||
{
|
||
if (TREE_CODE (arg1) == COMPOUND_EXPR)
|
||
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
|
||
fold (build (code, type,
|
||
arg0, TREE_OPERAND (arg1, 1))));
|
||
else if ((TREE_CODE (arg1) == COND_EXPR
|
||
|| (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<'
|
||
&& TREE_CODE_CLASS (code) != '<'))
|
||
&& (! TREE_SIDE_EFFECTS (arg0)
|
||
|| (current_function_decl != 0
|
||
&& ! contains_placeholder_p (arg0))))
|
||
{
|
||
tree test, true_value, false_value;
|
||
tree lhs = 0, rhs = 0;
|
||
|
||
if (TREE_CODE (arg1) == COND_EXPR)
|
||
{
|
||
test = TREE_OPERAND (arg1, 0);
|
||
true_value = TREE_OPERAND (arg1, 1);
|
||
false_value = TREE_OPERAND (arg1, 2);
|
||
}
|
||
else
|
||
{
|
||
tree testtype = TREE_TYPE (arg1);
|
||
test = arg1;
|
||
true_value = convert (testtype, integer_one_node);
|
||
false_value = convert (testtype, integer_zero_node);
|
||
}
|
||
|
||
/* If ARG0 is complex we want to make sure we only evaluate
|
||
it once. Though this is only required if it is volatile, it
|
||
might be more efficient even if it is not. However, if we
|
||
succeed in folding one part to a constant, we do not need
|
||
to make this SAVE_EXPR. Since we do this optimization
|
||
primarily to see if we do end up with constant and this
|
||
SAVE_EXPR interferes with later optimizations, suppressing
|
||
it when we can is important.
|
||
|
||
If we are not in a function, we can't make a SAVE_EXPR, so don't
|
||
try to do so. Don't try to see if the result is a constant
|
||
if an arm is a COND_EXPR since we get exponential behavior
|
||
in that case. */
|
||
|
||
if (TREE_CODE (arg0) != SAVE_EXPR && ! TREE_CONSTANT (arg0)
|
||
&& current_function_decl != 0
|
||
&& ((TREE_CODE (arg0) != VAR_DECL
|
||
&& TREE_CODE (arg0) != PARM_DECL)
|
||
|| TREE_SIDE_EFFECTS (arg0)))
|
||
{
|
||
if (TREE_CODE (true_value) != COND_EXPR)
|
||
lhs = fold (build (code, type, arg0, true_value));
|
||
|
||
if (TREE_CODE (false_value) != COND_EXPR)
|
||
rhs = fold (build (code, type, arg0, false_value));
|
||
|
||
if ((lhs == 0 || ! TREE_CONSTANT (lhs))
|
||
&& (rhs == 0 || !TREE_CONSTANT (rhs)))
|
||
arg0 = save_expr (arg0), lhs = rhs = 0;
|
||
}
|
||
|
||
if (lhs == 0)
|
||
lhs = fold (build (code, type, arg0, true_value));
|
||
if (rhs == 0)
|
||
rhs = fold (build (code, type, arg0, false_value));
|
||
|
||
test = fold (build (COND_EXPR, type, test, lhs, rhs));
|
||
|
||
if (TREE_CODE (arg0) == SAVE_EXPR)
|
||
return build (COMPOUND_EXPR, type,
|
||
convert (void_type_node, arg0),
|
||
strip_compound_expr (test, arg0));
|
||
else
|
||
return convert (type, test);
|
||
}
|
||
|
||
else if (TREE_CODE (arg0) == COMPOUND_EXPR)
|
||
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
|
||
fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
|
||
else if ((TREE_CODE (arg0) == COND_EXPR
|
||
|| (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
|
||
&& TREE_CODE_CLASS (code) != '<'))
|
||
&& (! TREE_SIDE_EFFECTS (arg1)
|
||
|| (current_function_decl != 0
|
||
&& ! contains_placeholder_p (arg1))))
|
||
{
|
||
tree test, true_value, false_value;
|
||
tree lhs = 0, rhs = 0;
|
||
|
||
if (TREE_CODE (arg0) == COND_EXPR)
|
||
{
|
||
test = TREE_OPERAND (arg0, 0);
|
||
true_value = TREE_OPERAND (arg0, 1);
|
||
false_value = TREE_OPERAND (arg0, 2);
|
||
}
|
||
else
|
||
{
|
||
tree testtype = TREE_TYPE (arg0);
|
||
test = arg0;
|
||
true_value = convert (testtype, integer_one_node);
|
||
false_value = convert (testtype, integer_zero_node);
|
||
}
|
||
|
||
if (TREE_CODE (arg1) != SAVE_EXPR && ! TREE_CONSTANT (arg0)
|
||
&& current_function_decl != 0
|
||
&& ((TREE_CODE (arg1) != VAR_DECL
|
||
&& TREE_CODE (arg1) != PARM_DECL)
|
||
|| TREE_SIDE_EFFECTS (arg1)))
|
||
{
|
||
if (TREE_CODE (true_value) != COND_EXPR)
|
||
lhs = fold (build (code, type, true_value, arg1));
|
||
|
||
if (TREE_CODE (false_value) != COND_EXPR)
|
||
rhs = fold (build (code, type, false_value, arg1));
|
||
|
||
if ((lhs == 0 || ! TREE_CONSTANT (lhs))
|
||
&& (rhs == 0 || !TREE_CONSTANT (rhs)))
|
||
arg1 = save_expr (arg1), lhs = rhs = 0;
|
||
}
|
||
|
||
if (lhs == 0)
|
||
lhs = fold (build (code, type, true_value, arg1));
|
||
|
||
if (rhs == 0)
|
||
rhs = fold (build (code, type, false_value, arg1));
|
||
|
||
test = fold (build (COND_EXPR, type, test, lhs, rhs));
|
||
if (TREE_CODE (arg1) == SAVE_EXPR)
|
||
return build (COMPOUND_EXPR, type,
|
||
convert (void_type_node, arg1),
|
||
strip_compound_expr (test, arg1));
|
||
else
|
||
return convert (type, test);
|
||
}
|
||
}
|
||
else if (TREE_CODE_CLASS (code) == '<'
|
||
&& TREE_CODE (arg0) == COMPOUND_EXPR)
|
||
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
|
||
fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
|
||
else if (TREE_CODE_CLASS (code) == '<'
|
||
&& TREE_CODE (arg1) == COMPOUND_EXPR)
|
||
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
|
||
fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
|
||
|
||
switch (code)
|
||
{
|
||
case INTEGER_CST:
|
||
case REAL_CST:
|
||
case STRING_CST:
|
||
case COMPLEX_CST:
|
||
case CONSTRUCTOR:
|
||
return t;
|
||
|
||
case CONST_DECL:
|
||
return fold (DECL_INITIAL (t));
|
||
|
||
case NOP_EXPR:
|
||
case FLOAT_EXPR:
|
||
case CONVERT_EXPR:
|
||
case FIX_TRUNC_EXPR:
|
||
/* Other kinds of FIX are not handled properly by fold_convert. */
|
||
|
||
if (TREE_TYPE (TREE_OPERAND (t, 0)) == TREE_TYPE (t))
|
||
return TREE_OPERAND (t, 0);
|
||
|
||
/* Handle cases of two conversions in a row. */
|
||
if (TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
|
||
|| TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR)
|
||
{
|
||
tree inside_type = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0));
|
||
tree inter_type = TREE_TYPE (TREE_OPERAND (t, 0));
|
||
tree final_type = TREE_TYPE (t);
|
||
int inside_int = INTEGRAL_TYPE_P (inside_type);
|
||
int inside_ptr = POINTER_TYPE_P (inside_type);
|
||
int inside_float = FLOAT_TYPE_P (inside_type);
|
||
int inside_prec = TYPE_PRECISION (inside_type);
|
||
int inside_unsignedp = TREE_UNSIGNED (inside_type);
|
||
int inter_int = INTEGRAL_TYPE_P (inter_type);
|
||
int inter_ptr = POINTER_TYPE_P (inter_type);
|
||
int inter_float = FLOAT_TYPE_P (inter_type);
|
||
int inter_prec = TYPE_PRECISION (inter_type);
|
||
int inter_unsignedp = TREE_UNSIGNED (inter_type);
|
||
int final_int = INTEGRAL_TYPE_P (final_type);
|
||
int final_ptr = POINTER_TYPE_P (final_type);
|
||
int final_float = FLOAT_TYPE_P (final_type);
|
||
int final_prec = TYPE_PRECISION (final_type);
|
||
int final_unsignedp = TREE_UNSIGNED (final_type);
|
||
|
||
/* In addition to the cases of two conversions in a row
|
||
handled below, if we are converting something to its own
|
||
type via an object of identical or wider precision, neither
|
||
conversion is needed. */
|
||
if (inside_type == final_type
|
||
&& ((inter_int && final_int) || (inter_float && final_float))
|
||
&& inter_prec >= final_prec)
|
||
return TREE_OPERAND (TREE_OPERAND (t, 0), 0);
|
||
|
||
/* Likewise, if the intermediate and final types are either both
|
||
float or both integer, we don't need the middle conversion if
|
||
it is wider than the final type and doesn't change the signedness
|
||
(for integers). Avoid this if the final type is a pointer
|
||
since then we sometimes need the inner conversion. Likewise if
|
||
the outer has a precision not equal to the size of its mode. */
|
||
if ((((inter_int || inter_ptr) && (inside_int || inside_ptr))
|
||
|| (inter_float && inside_float))
|
||
&& inter_prec >= inside_prec
|
||
&& (inter_float || inter_unsignedp == inside_unsignedp)
|
||
&& ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
|
||
&& TYPE_MODE (final_type) == TYPE_MODE (inter_type))
|
||
&& ! final_ptr)
|
||
return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
|
||
|
||
/* If we have a sign-extension of a zero-extended value, we can
|
||
replace that by a single zero-extension. */
|
||
if (inside_int && inter_int && final_int
|
||
&& inside_prec < inter_prec && inter_prec < final_prec
|
||
&& inside_unsignedp && !inter_unsignedp)
|
||
return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
|
||
|
||
/* Two conversions in a row are not needed unless:
|
||
- some conversion is floating-point (overstrict for now), or
|
||
- the intermediate type is narrower than both initial and
|
||
final, or
|
||
- the intermediate type and innermost type differ in signedness,
|
||
and the outermost type is wider than the intermediate, or
|
||
- the initial type is a pointer type and the precisions of the
|
||
intermediate and final types differ, or
|
||
- the final type is a pointer type and the precisions of the
|
||
initial and intermediate types differ. */
|
||
if (! inside_float && ! inter_float && ! final_float
|
||
&& (inter_prec > inside_prec || inter_prec > final_prec)
|
||
&& ! (inside_int && inter_int
|
||
&& inter_unsignedp != inside_unsignedp
|
||
&& inter_prec < final_prec)
|
||
&& ((inter_unsignedp && inter_prec > inside_prec)
|
||
== (final_unsignedp && final_prec > inter_prec))
|
||
&& ! (inside_ptr && inter_prec != final_prec)
|
||
&& ! (final_ptr && inside_prec != inter_prec)
|
||
&& ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
|
||
&& TYPE_MODE (final_type) == TYPE_MODE (inter_type))
|
||
&& ! final_ptr)
|
||
return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
|
||
}
|
||
|
||
if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR
|
||
&& TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))
|
||
/* Detect assigning a bitfield. */
|
||
&& !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF
|
||
&& DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1))))
|
||
{
|
||
/* Don't leave an assignment inside a conversion
|
||
unless assigning a bitfield. */
|
||
tree prev = TREE_OPERAND (t, 0);
|
||
TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1);
|
||
/* First do the assignment, then return converted constant. */
|
||
t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t));
|
||
TREE_USED (t) = 1;
|
||
return t;
|
||
}
|
||
if (!wins)
|
||
{
|
||
TREE_CONSTANT (t) = TREE_CONSTANT (arg0);
|
||
return t;
|
||
}
|
||
return fold_convert (t, arg0);
|
||
|
||
#if 0 /* This loses on &"foo"[0]. */
|
||
case ARRAY_REF:
|
||
{
|
||
int i;
|
||
|
||
/* Fold an expression like: "foo"[2] */
|
||
if (TREE_CODE (arg0) == STRING_CST
|
||
&& TREE_CODE (arg1) == INTEGER_CST
|
||
&& !TREE_INT_CST_HIGH (arg1)
|
||
&& (i = TREE_INT_CST_LOW (arg1)) < TREE_STRING_LENGTH (arg0))
|
||
{
|
||
t = build_int_2 (TREE_STRING_POINTER (arg0)[i], 0);
|
||
TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0));
|
||
force_fit_type (t, 0);
|
||
}
|
||
}
|
||
return t;
|
||
#endif /* 0 */
|
||
|
||
case COMPONENT_REF:
|
||
if (TREE_CODE (arg0) == CONSTRUCTOR)
|
||
{
|
||
tree m = purpose_member (arg1, CONSTRUCTOR_ELTS (arg0));
|
||
if (m)
|
||
t = TREE_VALUE (m);
|
||
}
|
||
return t;
|
||
|
||
case RANGE_EXPR:
|
||
TREE_CONSTANT (t) = wins;
|
||
return t;
|
||
|
||
case NEGATE_EXPR:
|
||
if (wins)
|
||
{
|
||
if (TREE_CODE (arg0) == INTEGER_CST)
|
||
{
|
||
HOST_WIDE_INT low, high;
|
||
int overflow = neg_double (TREE_INT_CST_LOW (arg0),
|
||
TREE_INT_CST_HIGH (arg0),
|
||
&low, &high);
|
||
t = build_int_2 (low, high);
|
||
TREE_TYPE (t) = type;
|
||
TREE_OVERFLOW (t)
|
||
= (TREE_OVERFLOW (arg0)
|
||
| force_fit_type (t, overflow && !TREE_UNSIGNED (type)));
|
||
TREE_CONSTANT_OVERFLOW (t)
|
||
= TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
|
||
}
|
||
else if (TREE_CODE (arg0) == REAL_CST)
|
||
t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
|
||
}
|
||
else if (TREE_CODE (arg0) == NEGATE_EXPR)
|
||
return TREE_OPERAND (arg0, 0);
|
||
|
||
/* Convert - (a - b) to (b - a) for non-floating-point. */
|
||
else if (TREE_CODE (arg0) == MINUS_EXPR && ! FLOAT_TYPE_P (type))
|
||
return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1),
|
||
TREE_OPERAND (arg0, 0));
|
||
|
||
return t;
|
||
|
||
case ABS_EXPR:
|
||
if (wins)
|
||
{
|
||
if (TREE_CODE (arg0) == INTEGER_CST)
|
||
{
|
||
if (! TREE_UNSIGNED (type)
|
||
&& TREE_INT_CST_HIGH (arg0) < 0)
|
||
{
|
||
HOST_WIDE_INT low, high;
|
||
int overflow = neg_double (TREE_INT_CST_LOW (arg0),
|
||
TREE_INT_CST_HIGH (arg0),
|
||
&low, &high);
|
||
t = build_int_2 (low, high);
|
||
TREE_TYPE (t) = type;
|
||
TREE_OVERFLOW (t)
|
||
= (TREE_OVERFLOW (arg0)
|
||
| force_fit_type (t, overflow));
|
||
TREE_CONSTANT_OVERFLOW (t)
|
||
= TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
|
||
}
|
||
}
|
||
else if (TREE_CODE (arg0) == REAL_CST)
|
||
{
|
||
if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0)))
|
||
t = build_real (type,
|
||
REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
|
||
}
|
||
}
|
||
else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
|
||
return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
|
||
return t;
|
||
|
||
case CONJ_EXPR:
|
||
if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
|
||
return arg0;
|
||
else if (TREE_CODE (arg0) == COMPLEX_EXPR)
|
||
return build (COMPLEX_EXPR, TREE_TYPE (arg0),
|
||
TREE_OPERAND (arg0, 0),
|
||
fold (build1 (NEGATE_EXPR,
|
||
TREE_TYPE (TREE_TYPE (arg0)),
|
||
TREE_OPERAND (arg0, 1))));
|
||
else if (TREE_CODE (arg0) == COMPLEX_CST)
|
||
return build_complex (type, TREE_OPERAND (arg0, 0),
|
||
fold (build1 (NEGATE_EXPR,
|
||
TREE_TYPE (TREE_TYPE (arg0)),
|
||
TREE_OPERAND (arg0, 1))));
|
||
else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
|
||
return fold (build (TREE_CODE (arg0), type,
|
||
fold (build1 (CONJ_EXPR, type,
|
||
TREE_OPERAND (arg0, 0))),
|
||
fold (build1 (CONJ_EXPR,
|
||
type, TREE_OPERAND (arg0, 1)))));
|
||
else if (TREE_CODE (arg0) == CONJ_EXPR)
|
||
return TREE_OPERAND (arg0, 0);
|
||
return t;
|
||
|
||
case BIT_NOT_EXPR:
|
||
if (wins)
|
||
{
|
||
t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
|
||
~ TREE_INT_CST_HIGH (arg0));
|
||
TREE_TYPE (t) = type;
|
||
force_fit_type (t, 0);
|
||
TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0);
|
||
TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0);
|
||
}
|
||
else if (TREE_CODE (arg0) == BIT_NOT_EXPR)
|
||
return TREE_OPERAND (arg0, 0);
|
||
return t;
|
||
|
||
case PLUS_EXPR:
|
||
/* A + (-B) -> A - B */
|
||
if (TREE_CODE (arg1) == NEGATE_EXPR)
|
||
return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
|
||
else if (! FLOAT_TYPE_P (type))
|
||
{
|
||
if (integer_zerop (arg1))
|
||
return non_lvalue (convert (type, arg0));
|
||
|
||
/* If we are adding two BIT_AND_EXPR's, both of which are and'ing
|
||
with a constant, and the two constants have no bits in common,
|
||
we should treat this as a BIT_IOR_EXPR since this may produce more
|
||
simplifications. */
|
||
if (TREE_CODE (arg0) == BIT_AND_EXPR
|
||
&& TREE_CODE (arg1) == BIT_AND_EXPR
|
||
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
|
||
&& TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
|
||
&& integer_zerop (const_binop (BIT_AND_EXPR,
|
||
TREE_OPERAND (arg0, 1),
|
||
TREE_OPERAND (arg1, 1), 0)))
|
||
{
|
||
code = BIT_IOR_EXPR;
|
||
goto bit_ior;
|
||
}
|
||
|
||
/* (A * C) + (B * C) -> (A+B) * C. Since we are most concerned
|
||
about the case where C is a constant, just try one of the
|
||
four possibilities. */
|
||
|
||
if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 1),
|
||
TREE_OPERAND (arg1, 1), 0))
|
||
return fold (build (MULT_EXPR, type,
|
||
fold (build (PLUS_EXPR, type,
|
||
TREE_OPERAND (arg0, 0),
|
||
TREE_OPERAND (arg1, 0))),
|
||
TREE_OPERAND (arg0, 1)));
|
||
}
|
||
/* In IEEE floating point, x+0 may not equal x. */
|
||
else if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
|
||
|| flag_fast_math)
|
||
&& real_zerop (arg1))
|
||
return non_lvalue (convert (type, arg0));
|
||
associate:
|
||
/* In most languages, can't associate operations on floats
|
||
through parentheses. Rather than remember where the parentheses
|
||
were, we don't associate floats at all. It shouldn't matter much.
|
||
However, associating multiplications is only very slightly
|
||
inaccurate, so do that if -ffast-math is specified. */
|
||
if (FLOAT_TYPE_P (type)
|
||
&& ! (flag_fast_math && code == MULT_EXPR))
|
||
goto binary;
|
||
|
||
/* The varsign == -1 cases happen only for addition and subtraction.
|
||
It says that the arg that was split was really CON minus VAR.
|
||
The rest of the code applies to all associative operations. */
|
||
if (!wins)
|
||
{
|
||
tree var, con;
|
||
int varsign;
|
||
|
||
if (split_tree (arg0, code, &var, &con, &varsign))
|
||
{
|
||
if (varsign == -1)
|
||
{
|
||
/* EXPR is (CON-VAR) +- ARG1. */
|
||
/* If it is + and VAR==ARG1, return just CONST. */
|
||
if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0))
|
||
return convert (TREE_TYPE (t), con);
|
||
|
||
/* If ARG0 is a constant, don't change things around;
|
||
instead keep all the constant computations together. */
|
||
|
||
if (TREE_CONSTANT (arg0))
|
||
return t;
|
||
|
||
/* Otherwise return (CON +- ARG1) - VAR. */
|
||
t = build (MINUS_EXPR, type,
|
||
fold (build (code, type, con, arg1)), var);
|
||
}
|
||
else
|
||
{
|
||
/* EXPR is (VAR+CON) +- ARG1. */
|
||
/* If it is - and VAR==ARG1, return just CONST. */
|
||
if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0))
|
||
return convert (TREE_TYPE (t), con);
|
||
|
||
/* If ARG0 is a constant, don't change things around;
|
||
instead keep all the constant computations together. */
|
||
|
||
if (TREE_CONSTANT (arg0))
|
||
return t;
|
||
|
||
/* Otherwise return VAR +- (ARG1 +- CON). */
|
||
tem = fold (build (code, type, arg1, con));
|
||
t = build (code, type, var, tem);
|
||
|
||
if (integer_zerop (tem)
|
||
&& (code == PLUS_EXPR || code == MINUS_EXPR))
|
||
return convert (type, var);
|
||
/* If we have x +/- (c - d) [c an explicit integer]
|
||
change it to x -/+ (d - c) since if d is relocatable
|
||
then the latter can be a single immediate insn
|
||
and the former cannot. */
|
||
if (TREE_CODE (tem) == MINUS_EXPR
|
||
&& TREE_CODE (TREE_OPERAND (tem, 0)) == INTEGER_CST)
|
||
{
|
||
tree tem1 = TREE_OPERAND (tem, 1);
|
||
TREE_OPERAND (tem, 1) = TREE_OPERAND (tem, 0);
|
||
TREE_OPERAND (tem, 0) = tem1;
|
||
TREE_SET_CODE (t,
|
||
(code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
|
||
}
|
||
}
|
||
return t;
|
||
}
|
||
|
||
if (split_tree (arg1, code, &var, &con, &varsign))
|
||
{
|
||
if (TREE_CONSTANT (arg1))
|
||
return t;
|
||
|
||
if (varsign == -1)
|
||
TREE_SET_CODE (t,
|
||
(code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
|
||
|
||
/* EXPR is ARG0 +- (CON +- VAR). */
|
||
if (TREE_CODE (t) == MINUS_EXPR
|
||
&& operand_equal_p (var, arg0, 0))
|
||
{
|
||
/* If VAR and ARG0 cancel, return just CON or -CON. */
|
||
if (code == PLUS_EXPR)
|
||
return convert (TREE_TYPE (t), con);
|
||
return fold (build1 (NEGATE_EXPR, TREE_TYPE (t),
|
||
convert (TREE_TYPE (t), con)));
|
||
}
|
||
|
||
t = build (TREE_CODE (t), type,
|
||
fold (build (code, TREE_TYPE (t), arg0, con)), var);
|
||
|
||
if (integer_zerop (TREE_OPERAND (t, 0))
|
||
&& TREE_CODE (t) == PLUS_EXPR)
|
||
return convert (TREE_TYPE (t), var);
|
||
return t;
|
||
}
|
||
}
|
||
binary:
|
||
#if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC)
|
||
if (TREE_CODE (arg1) == REAL_CST)
|
||
return t;
|
||
#endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */
|
||
if (wins)
|
||
t1 = const_binop (code, arg0, arg1, 0);
|
||
if (t1 != NULL_TREE)
|
||
{
|
||
/* The return value should always have
|
||
the same type as the original expression. */
|
||
if (TREE_TYPE (t1) != TREE_TYPE (t))
|
||
t1 = convert (TREE_TYPE (t), t1);
|
||
|
||
return t1;
|
||
}
|
||
return t;
|
||
|
||
case MINUS_EXPR:
|
||
if (! FLOAT_TYPE_P (type))
|
||
{
|
||
if (! wins && integer_zerop (arg0))
|
||
return build1 (NEGATE_EXPR, type, arg1);
|
||
if (integer_zerop (arg1))
|
||
return non_lvalue (convert (type, arg0));
|
||
|
||
/* (A * C) - (B * C) -> (A-B) * C. Since we are most concerned
|
||
about the case where C is a constant, just try one of the
|
||
four possibilities. */
|
||
|
||
if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 1),
|
||
TREE_OPERAND (arg1, 1), 0))
|
||
return fold (build (MULT_EXPR, type,
|
||
fold (build (MINUS_EXPR, type,
|
||
TREE_OPERAND (arg0, 0),
|
||
TREE_OPERAND (arg1, 0))),
|
||
TREE_OPERAND (arg0, 1)));
|
||
}
|
||
/* Convert A - (-B) to A + B. */
|
||
else if (TREE_CODE (arg1) == NEGATE_EXPR)
|
||
return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
|
||
|
||
else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
|
||
|| flag_fast_math)
|
||
{
|
||
/* Except with IEEE floating point, 0-x equals -x. */
|
||
if (! wins && real_zerop (arg0))
|
||
return build1 (NEGATE_EXPR, type, arg1);
|
||
/* Except with IEEE floating point, x-0 equals x. */
|
||
if (real_zerop (arg1))
|
||
return non_lvalue (convert (type, arg0));
|
||
}
|
||
|
||
/* Fold &x - &x. This can happen from &x.foo - &x.
|
||
This is unsafe for certain floats even in non-IEEE formats.
|
||
In IEEE, it is unsafe because it does wrong for NaNs.
|
||
Also note that operand_equal_p is always false if an operand
|
||
is volatile. */
|
||
|
||
if ((! FLOAT_TYPE_P (type) || flag_fast_math)
|
||
&& operand_equal_p (arg0, arg1, 0))
|
||
return convert (type, integer_zero_node);
|
||
|
||
goto associate;
|
||
|
||
case MULT_EXPR:
|
||
if (! FLOAT_TYPE_P (type))
|
||
{
|
||
if (integer_zerop (arg1))
|
||
return omit_one_operand (type, arg1, arg0);
|
||
if (integer_onep (arg1))
|
||
return non_lvalue (convert (type, arg0));
|
||
|
||
/* ((A / C) * C) is A if the division is an
|
||
EXACT_DIV_EXPR. Since C is normally a constant,
|
||
just check for one of the four possibilities. */
|
||
|
||
if (TREE_CODE (arg0) == EXACT_DIV_EXPR
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
|
||
return TREE_OPERAND (arg0, 0);
|
||
|
||
/* (a * (1 << b)) is (a << b) */
|
||
if (TREE_CODE (arg1) == LSHIFT_EXPR
|
||
&& integer_onep (TREE_OPERAND (arg1, 0)))
|
||
return fold (build (LSHIFT_EXPR, type, arg0,
|
||
TREE_OPERAND (arg1, 1)));
|
||
if (TREE_CODE (arg0) == LSHIFT_EXPR
|
||
&& integer_onep (TREE_OPERAND (arg0, 0)))
|
||
return fold (build (LSHIFT_EXPR, type, arg1,
|
||
TREE_OPERAND (arg0, 1)));
|
||
}
|
||
else
|
||
{
|
||
/* x*0 is 0, except for IEEE floating point. */
|
||
if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
|
||
|| flag_fast_math)
|
||
&& real_zerop (arg1))
|
||
return omit_one_operand (type, arg1, arg0);
|
||
/* In IEEE floating point, x*1 is not equivalent to x for snans.
|
||
However, ANSI says we can drop signals,
|
||
so we can do this anyway. */
|
||
if (real_onep (arg1))
|
||
return non_lvalue (convert (type, arg0));
|
||
/* x*2 is x+x */
|
||
if (! wins && real_twop (arg1) && current_function_decl != 0
|
||
&& ! contains_placeholder_p (arg0))
|
||
{
|
||
tree arg = save_expr (arg0);
|
||
return build (PLUS_EXPR, type, arg, arg);
|
||
}
|
||
}
|
||
goto associate;
|
||
|
||
case BIT_IOR_EXPR:
|
||
bit_ior:
|
||
{
|
||
register enum tree_code code0, code1;
|
||
|
||
if (integer_all_onesp (arg1))
|
||
return omit_one_operand (type, arg1, arg0);
|
||
if (integer_zerop (arg1))
|
||
return non_lvalue (convert (type, arg0));
|
||
t1 = distribute_bit_expr (code, type, arg0, arg1);
|
||
if (t1 != NULL_TREE)
|
||
return t1;
|
||
|
||
/* (A << C1) | (A >> C2) if A is unsigned and C1+C2 is the size of A
|
||
is a rotate of A by C1 bits. */
|
||
/* (A << B) | (A >> (Z - B)) if A is unsigned and Z is the size of A
|
||
is a rotate of A by B bits. */
|
||
|
||
code0 = TREE_CODE (arg0);
|
||
code1 = TREE_CODE (arg1);
|
||
if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR)
|
||
|| (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR))
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0)
|
||
&& TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
|
||
{
|
||
register tree tree01, tree11;
|
||
register enum tree_code code01, code11;
|
||
|
||
tree01 = TREE_OPERAND (arg0, 1);
|
||
tree11 = TREE_OPERAND (arg1, 1);
|
||
code01 = TREE_CODE (tree01);
|
||
code11 = TREE_CODE (tree11);
|
||
if (code01 == INTEGER_CST
|
||
&& code11 == INTEGER_CST
|
||
&& TREE_INT_CST_HIGH (tree01) == 0
|
||
&& TREE_INT_CST_HIGH (tree11) == 0
|
||
&& ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11))
|
||
== TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
|
||
return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
|
||
code0 == LSHIFT_EXPR ? tree01 : tree11);
|
||
else if (code11 == MINUS_EXPR
|
||
&& TREE_CODE (TREE_OPERAND (tree11, 0)) == INTEGER_CST
|
||
&& TREE_INT_CST_HIGH (TREE_OPERAND (tree11, 0)) == 0
|
||
&& TREE_INT_CST_LOW (TREE_OPERAND (tree11, 0))
|
||
== TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
|
||
&& operand_equal_p (tree01, TREE_OPERAND (tree11, 1), 0))
|
||
return build (code0 == LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
|
||
type, TREE_OPERAND (arg0, 0), tree01);
|
||
else if (code01 == MINUS_EXPR
|
||
&& TREE_CODE (TREE_OPERAND (tree01, 0)) == INTEGER_CST
|
||
&& TREE_INT_CST_HIGH (TREE_OPERAND (tree01, 0)) == 0
|
||
&& TREE_INT_CST_LOW (TREE_OPERAND (tree01, 0))
|
||
== TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
|
||
&& operand_equal_p (tree11, TREE_OPERAND (tree01, 1), 0))
|
||
return build (code0 != LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
|
||
type, TREE_OPERAND (arg0, 0), tree11);
|
||
}
|
||
|
||
goto associate;
|
||
}
|
||
|
||
case BIT_XOR_EXPR:
|
||
if (integer_zerop (arg1))
|
||
return non_lvalue (convert (type, arg0));
|
||
if (integer_all_onesp (arg1))
|
||
return fold (build1 (BIT_NOT_EXPR, type, arg0));
|
||
goto associate;
|
||
|
||
case BIT_AND_EXPR:
|
||
bit_and:
|
||
if (integer_all_onesp (arg1))
|
||
return non_lvalue (convert (type, arg0));
|
||
if (integer_zerop (arg1))
|
||
return omit_one_operand (type, arg1, arg0);
|
||
t1 = distribute_bit_expr (code, type, arg0, arg1);
|
||
if (t1 != NULL_TREE)
|
||
return t1;
|
||
/* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */
|
||
if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR
|
||
&& TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0))))
|
||
{
|
||
int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0)));
|
||
if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
|
||
&& (~TREE_INT_CST_LOW (arg0)
|
||
& (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
|
||
return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0));
|
||
}
|
||
if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
|
||
&& TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
|
||
{
|
||
int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
|
||
if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
|
||
&& (~TREE_INT_CST_LOW (arg1)
|
||
& (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
|
||
return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0));
|
||
}
|
||
goto associate;
|
||
|
||
case BIT_ANDTC_EXPR:
|
||
if (integer_all_onesp (arg0))
|
||
return non_lvalue (convert (type, arg1));
|
||
if (integer_zerop (arg0))
|
||
return omit_one_operand (type, arg0, arg1);
|
||
if (TREE_CODE (arg1) == INTEGER_CST)
|
||
{
|
||
arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1));
|
||
code = BIT_AND_EXPR;
|
||
goto bit_and;
|
||
}
|
||
goto binary;
|
||
|
||
case RDIV_EXPR:
|
||
/* In most cases, do nothing with a divide by zero. */
|
||
#if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
|
||
#ifndef REAL_INFINITY
|
||
if (TREE_CODE (arg1) == REAL_CST && real_zerop (arg1))
|
||
return t;
|
||
#endif
|
||
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
|
||
|
||
/* In IEEE floating point, x/1 is not equivalent to x for snans.
|
||
However, ANSI says we can drop signals, so we can do this anyway. */
|
||
if (real_onep (arg1))
|
||
return non_lvalue (convert (type, arg0));
|
||
|
||
/* If ARG1 is a constant, we can convert this to a multiply by the
|
||
reciprocal. This does not have the same rounding properties,
|
||
so only do this if -ffast-math. We can actually always safely
|
||
do it if ARG1 is a power of two, but it's hard to tell if it is
|
||
or not in a portable manner. */
|
||
if (TREE_CODE (arg1) == REAL_CST)
|
||
{
|
||
if (flag_fast_math
|
||
&& 0 != (tem = const_binop (code, build_real (type, dconst1),
|
||
arg1, 0)))
|
||
return fold (build (MULT_EXPR, type, arg0, tem));
|
||
/* Find the reciprocal if optimizing and the result is exact. */
|
||
else if (optimize)
|
||
{
|
||
REAL_VALUE_TYPE r;
|
||
r = TREE_REAL_CST (arg1);
|
||
if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r))
|
||
{
|
||
tem = build_real (type, r);
|
||
return fold (build (MULT_EXPR, type, arg0, tem));
|
||
}
|
||
}
|
||
}
|
||
goto binary;
|
||
|
||
case TRUNC_DIV_EXPR:
|
||
case ROUND_DIV_EXPR:
|
||
case FLOOR_DIV_EXPR:
|
||
case CEIL_DIV_EXPR:
|
||
case EXACT_DIV_EXPR:
|
||
if (integer_onep (arg1))
|
||
return non_lvalue (convert (type, arg0));
|
||
if (integer_zerop (arg1))
|
||
return t;
|
||
|
||
/* If arg0 is a multiple of arg1, then rewrite to the fastest div
|
||
operation, EXACT_DIV_EXPR.
|
||
|
||
Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
|
||
At one time others generated faster code, it's not clear if they do
|
||
after the last round to changes to the DIV code in expmed.c. */
|
||
if ((code == CEIL_DIV_EXPR || code == FLOOR_DIV_EXPR)
|
||
&& multiple_of_p (type, arg0, arg1))
|
||
return fold (build (EXACT_DIV_EXPR, type, arg0, arg1));
|
||
|
||
/* If we have ((a / C1) / C2) where both division are the same type, try
|
||
to simplify. First see if C1 * C2 overflows or not. */
|
||
if (TREE_CODE (arg0) == code && TREE_CODE (arg1) == INTEGER_CST
|
||
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
|
||
{
|
||
tree new_divisor;
|
||
|
||
new_divisor = const_binop (MULT_EXPR, TREE_OPERAND (arg0, 1), arg1, 0);
|
||
tem = const_binop (FLOOR_DIV_EXPR, new_divisor, arg1, 0);
|
||
|
||
if (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_LOW (tem)
|
||
&& TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_HIGH (tem))
|
||
{
|
||
/* If no overflow, divide by C1*C2. */
|
||
return fold (build (code, type, TREE_OPERAND (arg0, 0), new_divisor));
|
||
}
|
||
}
|
||
|
||
/* Look for ((a * C1) / C3) or (((a * C1) + C2) / C3),
|
||
where C1 % C3 == 0 or C3 % C1 == 0. We can simplify these
|
||
expressions, which often appear in the offsets or sizes of
|
||
objects with a varying size. Only deal with positive divisors
|
||
and multiplicands. If C2 is negative, we must have C2 % C3 == 0.
|
||
|
||
Look for NOPs and SAVE_EXPRs inside. */
|
||
|
||
if (TREE_CODE (arg1) == INTEGER_CST
|
||
&& tree_int_cst_sgn (arg1) >= 0)
|
||
{
|
||
int have_save_expr = 0;
|
||
tree c2 = integer_zero_node;
|
||
tree xarg0 = arg0;
|
||
|
||
if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
|
||
have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
|
||
|
||
STRIP_NOPS (xarg0);
|
||
|
||
/* Look inside the dividend and simplify using EXACT_DIV_EXPR
|
||
if possible. */
|
||
if (TREE_CODE (xarg0) == MULT_EXPR
|
||
&& multiple_of_p (type, TREE_OPERAND (xarg0, 0), arg1))
|
||
{
|
||
tree t;
|
||
|
||
t = fold (build (MULT_EXPR, type,
|
||
fold (build (EXACT_DIV_EXPR, type,
|
||
TREE_OPERAND (xarg0, 0), arg1)),
|
||
TREE_OPERAND (xarg0, 1)));
|
||
if (have_save_expr)
|
||
t = save_expr (t);
|
||
return t;
|
||
|
||
}
|
||
|
||
if (TREE_CODE (xarg0) == MULT_EXPR
|
||
&& multiple_of_p (type, TREE_OPERAND (xarg0, 1), arg1))
|
||
{
|
||
tree t;
|
||
|
||
t = fold (build (MULT_EXPR, type,
|
||
fold (build (EXACT_DIV_EXPR, type,
|
||
TREE_OPERAND (xarg0, 1), arg1)),
|
||
TREE_OPERAND (xarg0, 0)));
|
||
if (have_save_expr)
|
||
t = save_expr (t);
|
||
return t;
|
||
}
|
||
|
||
if (TREE_CODE (xarg0) == PLUS_EXPR
|
||
&& TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
|
||
c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
|
||
else if (TREE_CODE (xarg0) == MINUS_EXPR
|
||
&& TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
|
||
/* If we are doing this computation unsigned, the negate
|
||
is incorrect. */
|
||
&& ! TREE_UNSIGNED (type))
|
||
{
|
||
c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
|
||
xarg0 = TREE_OPERAND (xarg0, 0);
|
||
}
|
||
|
||
if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
|
||
have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
|
||
|
||
STRIP_NOPS (xarg0);
|
||
|
||
if (TREE_CODE (xarg0) == MULT_EXPR
|
||
&& TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
|
||
&& tree_int_cst_sgn (TREE_OPERAND (xarg0, 1)) >= 0
|
||
&& (integer_zerop (const_binop (TRUNC_MOD_EXPR,
|
||
TREE_OPERAND (xarg0, 1), arg1, 1))
|
||
|| integer_zerop (const_binop (TRUNC_MOD_EXPR, arg1,
|
||
TREE_OPERAND (xarg0, 1), 1)))
|
||
&& (tree_int_cst_sgn (c2) >= 0
|
||
|| integer_zerop (const_binop (TRUNC_MOD_EXPR, c2,
|
||
arg1, 1))))
|
||
{
|
||
tree outer_div = integer_one_node;
|
||
tree c1 = TREE_OPERAND (xarg0, 1);
|
||
tree c3 = arg1;
|
||
|
||
/* If C3 > C1, set them equal and do a divide by
|
||
C3/C1 at the end of the operation. */
|
||
if (tree_int_cst_lt (c1, c3))
|
||
outer_div = const_binop (code, c3, c1, 0), c3 = c1;
|
||
|
||
/* The result is A * (C1/C3) + (C2/C3). */
|
||
t = fold (build (PLUS_EXPR, type,
|
||
fold (build (MULT_EXPR, type,
|
||
TREE_OPERAND (xarg0, 0),
|
||
const_binop (code, c1, c3, 1))),
|
||
const_binop (code, c2, c3, 1)));
|
||
|
||
if (! integer_onep (outer_div))
|
||
t = fold (build (code, type, t, convert (type, outer_div)));
|
||
|
||
if (have_save_expr)
|
||
t = save_expr (t);
|
||
|
||
return t;
|
||
}
|
||
}
|
||
|
||
goto binary;
|
||
|
||
case CEIL_MOD_EXPR:
|
||
case FLOOR_MOD_EXPR:
|
||
case ROUND_MOD_EXPR:
|
||
case TRUNC_MOD_EXPR:
|
||
if (integer_onep (arg1))
|
||
return omit_one_operand (type, integer_zero_node, arg0);
|
||
if (integer_zerop (arg1))
|
||
return t;
|
||
|
||
/* Look for ((a * C1) % C3) or (((a * C1) + C2) % C3),
|
||
where C1 % C3 == 0. Handle similarly to the division case,
|
||
but don't bother with SAVE_EXPRs. */
|
||
|
||
if (TREE_CODE (arg1) == INTEGER_CST
|
||
&& ! integer_zerop (arg1))
|
||
{
|
||
tree c2 = integer_zero_node;
|
||
tree xarg0 = arg0;
|
||
|
||
if (TREE_CODE (xarg0) == PLUS_EXPR
|
||
&& TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
|
||
c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
|
||
else if (TREE_CODE (xarg0) == MINUS_EXPR
|
||
&& TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
|
||
&& ! TREE_UNSIGNED (type))
|
||
{
|
||
c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
|
||
xarg0 = TREE_OPERAND (xarg0, 0);
|
||
}
|
||
|
||
STRIP_NOPS (xarg0);
|
||
|
||
if (TREE_CODE (xarg0) == MULT_EXPR
|
||
&& TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
|
||
&& integer_zerop (const_binop (TRUNC_MOD_EXPR,
|
||
TREE_OPERAND (xarg0, 1),
|
||
arg1, 1))
|
||
&& tree_int_cst_sgn (c2) >= 0)
|
||
/* The result is (C2%C3). */
|
||
return omit_one_operand (type, const_binop (code, c2, arg1, 1),
|
||
TREE_OPERAND (xarg0, 0));
|
||
}
|
||
|
||
goto binary;
|
||
|
||
case LSHIFT_EXPR:
|
||
case RSHIFT_EXPR:
|
||
case LROTATE_EXPR:
|
||
case RROTATE_EXPR:
|
||
if (integer_zerop (arg1))
|
||
return non_lvalue (convert (type, arg0));
|
||
/* Since negative shift count is not well-defined,
|
||
don't try to compute it in the compiler. */
|
||
if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0)
|
||
return t;
|
||
/* Rewrite an LROTATE_EXPR by a constant into an
|
||
RROTATE_EXPR by a new constant. */
|
||
if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST)
|
||
{
|
||
TREE_SET_CODE (t, RROTATE_EXPR);
|
||
code = RROTATE_EXPR;
|
||
TREE_OPERAND (t, 1) = arg1
|
||
= const_binop
|
||
(MINUS_EXPR,
|
||
convert (TREE_TYPE (arg1),
|
||
build_int_2 (GET_MODE_BITSIZE (TYPE_MODE (type)), 0)),
|
||
arg1, 0);
|
||
if (tree_int_cst_sgn (arg1) < 0)
|
||
return t;
|
||
}
|
||
|
||
/* If we have a rotate of a bit operation with the rotate count and
|
||
the second operand of the bit operation both constant,
|
||
permute the two operations. */
|
||
if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
|
||
&& (TREE_CODE (arg0) == BIT_AND_EXPR
|
||
|| TREE_CODE (arg0) == BIT_ANDTC_EXPR
|
||
|| TREE_CODE (arg0) == BIT_IOR_EXPR
|
||
|| TREE_CODE (arg0) == BIT_XOR_EXPR)
|
||
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
|
||
return fold (build (TREE_CODE (arg0), type,
|
||
fold (build (code, type,
|
||
TREE_OPERAND (arg0, 0), arg1)),
|
||
fold (build (code, type,
|
||
TREE_OPERAND (arg0, 1), arg1))));
|
||
|
||
/* Two consecutive rotates adding up to the width of the mode can
|
||
be ignored. */
|
||
if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
|
||
&& TREE_CODE (arg0) == RROTATE_EXPR
|
||
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
|
||
&& TREE_INT_CST_HIGH (arg1) == 0
|
||
&& TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
|
||
&& ((TREE_INT_CST_LOW (arg1)
|
||
+ TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)))
|
||
== GET_MODE_BITSIZE (TYPE_MODE (type))))
|
||
return TREE_OPERAND (arg0, 0);
|
||
|
||
goto binary;
|
||
|
||
case MIN_EXPR:
|
||
if (operand_equal_p (arg0, arg1, 0))
|
||
return arg0;
|
||
if (INTEGRAL_TYPE_P (type)
|
||
&& operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1))
|
||
return omit_one_operand (type, arg1, arg0);
|
||
goto associate;
|
||
|
||
case MAX_EXPR:
|
||
if (operand_equal_p (arg0, arg1, 0))
|
||
return arg0;
|
||
if (INTEGRAL_TYPE_P (type)
|
||
&& TYPE_MAX_VALUE (type)
|
||
&& operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
|
||
return omit_one_operand (type, arg1, arg0);
|
||
goto associate;
|
||
|
||
case TRUTH_NOT_EXPR:
|
||
/* Note that the operand of this must be an int
|
||
and its values must be 0 or 1.
|
||
("true" is a fixed value perhaps depending on the language,
|
||
but we don't handle values other than 1 correctly yet.) */
|
||
tem = invert_truthvalue (arg0);
|
||
/* Avoid infinite recursion. */
|
||
if (TREE_CODE (tem) == TRUTH_NOT_EXPR)
|
||
return t;
|
||
return convert (type, tem);
|
||
|
||
case TRUTH_ANDIF_EXPR:
|
||
/* Note that the operands of this must be ints
|
||
and their values must be 0 or 1.
|
||
("true" is a fixed value perhaps depending on the language.) */
|
||
/* If first arg is constant zero, return it. */
|
||
if (integer_zerop (arg0))
|
||
return arg0;
|
||
case TRUTH_AND_EXPR:
|
||
/* If either arg is constant true, drop it. */
|
||
if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
|
||
return non_lvalue (arg1);
|
||
if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
|
||
return non_lvalue (arg0);
|
||
/* If second arg is constant zero, result is zero, but first arg
|
||
must be evaluated. */
|
||
if (integer_zerop (arg1))
|
||
return omit_one_operand (type, arg1, arg0);
|
||
/* Likewise for first arg, but note that only the TRUTH_AND_EXPR
|
||
case will be handled here. */
|
||
if (integer_zerop (arg0))
|
||
return omit_one_operand (type, arg0, arg1);
|
||
|
||
truth_andor:
|
||
/* We only do these simplifications if we are optimizing. */
|
||
if (!optimize)
|
||
return t;
|
||
|
||
/* Check for things like (A || B) && (A || C). We can convert this
|
||
to A || (B && C). Note that either operator can be any of the four
|
||
truth and/or operations and the transformation will still be
|
||
valid. Also note that we only care about order for the
|
||
ANDIF and ORIF operators. If B contains side effects, this
|
||
might change the truth-value of A. */
|
||
if (TREE_CODE (arg0) == TREE_CODE (arg1)
|
||
&& (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR
|
||
|| TREE_CODE (arg0) == TRUTH_ORIF_EXPR
|
||
|| TREE_CODE (arg0) == TRUTH_AND_EXPR
|
||
|| TREE_CODE (arg0) == TRUTH_OR_EXPR)
|
||
&& ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg0, 1)))
|
||
{
|
||
tree a00 = TREE_OPERAND (arg0, 0);
|
||
tree a01 = TREE_OPERAND (arg0, 1);
|
||
tree a10 = TREE_OPERAND (arg1, 0);
|
||
tree a11 = TREE_OPERAND (arg1, 1);
|
||
int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR
|
||
|| TREE_CODE (arg0) == TRUTH_AND_EXPR)
|
||
&& (code == TRUTH_AND_EXPR
|
||
|| code == TRUTH_OR_EXPR));
|
||
|
||
if (operand_equal_p (a00, a10, 0))
|
||
return fold (build (TREE_CODE (arg0), type, a00,
|
||
fold (build (code, type, a01, a11))));
|
||
else if (commutative && operand_equal_p (a00, a11, 0))
|
||
return fold (build (TREE_CODE (arg0), type, a00,
|
||
fold (build (code, type, a01, a10))));
|
||
else if (commutative && operand_equal_p (a01, a10, 0))
|
||
return fold (build (TREE_CODE (arg0), type, a01,
|
||
fold (build (code, type, a00, a11))));
|
||
|
||
/* This case if tricky because we must either have commutative
|
||
operators or else A10 must not have side-effects. */
|
||
|
||
else if ((commutative || ! TREE_SIDE_EFFECTS (a10))
|
||
&& operand_equal_p (a01, a11, 0))
|
||
return fold (build (TREE_CODE (arg0), type,
|
||
fold (build (code, type, a00, a10)),
|
||
a01));
|
||
}
|
||
|
||
/* See if we can build a range comparison. */
|
||
if (0 != (tem = fold_range_test (t)))
|
||
return tem;
|
||
|
||
/* Check for the possibility of merging component references. If our
|
||
lhs is another similar operation, try to merge its rhs with our
|
||
rhs. Then try to merge our lhs and rhs. */
|
||
if (TREE_CODE (arg0) == code
|
||
&& 0 != (tem = fold_truthop (code, type,
|
||
TREE_OPERAND (arg0, 1), arg1)))
|
||
return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
|
||
|
||
if ((tem = fold_truthop (code, type, arg0, arg1)) != 0)
|
||
return tem;
|
||
|
||
return t;
|
||
|
||
case TRUTH_ORIF_EXPR:
|
||
/* Note that the operands of this must be ints
|
||
and their values must be 0 or true.
|
||
("true" is a fixed value perhaps depending on the language.) */
|
||
/* If first arg is constant true, return it. */
|
||
if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
|
||
return arg0;
|
||
case TRUTH_OR_EXPR:
|
||
/* If either arg is constant zero, drop it. */
|
||
if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
|
||
return non_lvalue (arg1);
|
||
if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1))
|
||
return non_lvalue (arg0);
|
||
/* If second arg is constant true, result is true, but we must
|
||
evaluate first arg. */
|
||
if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
|
||
return omit_one_operand (type, arg1, arg0);
|
||
/* Likewise for first arg, but note this only occurs here for
|
||
TRUTH_OR_EXPR. */
|
||
if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
|
||
return omit_one_operand (type, arg0, arg1);
|
||
goto truth_andor;
|
||
|
||
case TRUTH_XOR_EXPR:
|
||
/* If either arg is constant zero, drop it. */
|
||
if (integer_zerop (arg0))
|
||
return non_lvalue (arg1);
|
||
if (integer_zerop (arg1))
|
||
return non_lvalue (arg0);
|
||
/* If either arg is constant true, this is a logical inversion. */
|
||
if (integer_onep (arg0))
|
||
return non_lvalue (invert_truthvalue (arg1));
|
||
if (integer_onep (arg1))
|
||
return non_lvalue (invert_truthvalue (arg0));
|
||
return t;
|
||
|
||
case EQ_EXPR:
|
||
case NE_EXPR:
|
||
case LT_EXPR:
|
||
case GT_EXPR:
|
||
case LE_EXPR:
|
||
case GE_EXPR:
|
||
/* If one arg is a constant integer, put it last. */
|
||
if (TREE_CODE (arg0) == INTEGER_CST
|
||
&& TREE_CODE (arg1) != INTEGER_CST)
|
||
{
|
||
TREE_OPERAND (t, 0) = arg1;
|
||
TREE_OPERAND (t, 1) = arg0;
|
||
arg0 = TREE_OPERAND (t, 0);
|
||
arg1 = TREE_OPERAND (t, 1);
|
||
code = swap_tree_comparison (code);
|
||
TREE_SET_CODE (t, code);
|
||
}
|
||
|
||
/* Convert foo++ == CONST into ++foo == CONST + INCR.
|
||
First, see if one arg is constant; find the constant arg
|
||
and the other one. */
|
||
{
|
||
tree constop = 0, varop = NULL_TREE;
|
||
int constopnum = -1;
|
||
|
||
if (TREE_CONSTANT (arg1))
|
||
constopnum = 1, constop = arg1, varop = arg0;
|
||
if (TREE_CONSTANT (arg0))
|
||
constopnum = 0, constop = arg0, varop = arg1;
|
||
|
||
if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR)
|
||
{
|
||
/* This optimization is invalid for ordered comparisons
|
||
if CONST+INCR overflows or if foo+incr might overflow.
|
||
This optimization is invalid for floating point due to rounding.
|
||
For pointer types we assume overflow doesn't happen. */
|
||
if (POINTER_TYPE_P (TREE_TYPE (varop))
|
||
|| (! FLOAT_TYPE_P (TREE_TYPE (varop))
|
||
&& (code == EQ_EXPR || code == NE_EXPR)))
|
||
{
|
||
tree newconst
|
||
= fold (build (PLUS_EXPR, TREE_TYPE (varop),
|
||
constop, TREE_OPERAND (varop, 1)));
|
||
TREE_SET_CODE (varop, PREINCREMENT_EXPR);
|
||
|
||
/* If VAROP is a reference to a bitfield, we must mask
|
||
the constant by the width of the field. */
|
||
if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
|
||
&& DECL_BIT_FIELD(TREE_OPERAND
|
||
(TREE_OPERAND (varop, 0), 1)))
|
||
{
|
||
int size
|
||
= TREE_INT_CST_LOW (DECL_SIZE
|
||
(TREE_OPERAND
|
||
(TREE_OPERAND (varop, 0), 1)));
|
||
tree mask, unsigned_type;
|
||
int precision;
|
||
tree folded_compare;
|
||
|
||
/* First check whether the comparison would come out
|
||
always the same. If we don't do that we would
|
||
change the meaning with the masking. */
|
||
if (constopnum == 0)
|
||
folded_compare = fold (build (code, type, constop,
|
||
TREE_OPERAND (varop, 0)));
|
||
else
|
||
folded_compare = fold (build (code, type,
|
||
TREE_OPERAND (varop, 0),
|
||
constop));
|
||
if (integer_zerop (folded_compare)
|
||
|| integer_onep (folded_compare))
|
||
return omit_one_operand (type, folded_compare, varop);
|
||
|
||
unsigned_type = type_for_size (size, 1);
|
||
precision = TYPE_PRECISION (unsigned_type);
|
||
mask = build_int_2 (~0, ~0);
|
||
TREE_TYPE (mask) = unsigned_type;
|
||
force_fit_type (mask, 0);
|
||
mask = const_binop (RSHIFT_EXPR, mask,
|
||
size_int (precision - size), 0);
|
||
newconst = fold (build (BIT_AND_EXPR,
|
||
TREE_TYPE (varop), newconst,
|
||
convert (TREE_TYPE (varop),
|
||
mask)));
|
||
}
|
||
|
||
|
||
t = build (code, type, TREE_OPERAND (t, 0),
|
||
TREE_OPERAND (t, 1));
|
||
TREE_OPERAND (t, constopnum) = newconst;
|
||
return t;
|
||
}
|
||
}
|
||
else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
|
||
{
|
||
if (POINTER_TYPE_P (TREE_TYPE (varop))
|
||
|| (! FLOAT_TYPE_P (TREE_TYPE (varop))
|
||
&& (code == EQ_EXPR || code == NE_EXPR)))
|
||
{
|
||
tree newconst
|
||
= fold (build (MINUS_EXPR, TREE_TYPE (varop),
|
||
constop, TREE_OPERAND (varop, 1)));
|
||
TREE_SET_CODE (varop, PREDECREMENT_EXPR);
|
||
|
||
if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
|
||
&& DECL_BIT_FIELD(TREE_OPERAND
|
||
(TREE_OPERAND (varop, 0), 1)))
|
||
{
|
||
int size
|
||
= TREE_INT_CST_LOW (DECL_SIZE
|
||
(TREE_OPERAND
|
||
(TREE_OPERAND (varop, 0), 1)));
|
||
tree mask, unsigned_type;
|
||
int precision;
|
||
tree folded_compare;
|
||
|
||
if (constopnum == 0)
|
||
folded_compare = fold (build (code, type, constop,
|
||
TREE_OPERAND (varop, 0)));
|
||
else
|
||
folded_compare = fold (build (code, type,
|
||
TREE_OPERAND (varop, 0),
|
||
constop));
|
||
if (integer_zerop (folded_compare)
|
||
|| integer_onep (folded_compare))
|
||
return omit_one_operand (type, folded_compare, varop);
|
||
|
||
unsigned_type = type_for_size (size, 1);
|
||
precision = TYPE_PRECISION (unsigned_type);
|
||
mask = build_int_2 (~0, ~0);
|
||
TREE_TYPE (mask) = TREE_TYPE (varop);
|
||
force_fit_type (mask, 0);
|
||
mask = const_binop (RSHIFT_EXPR, mask,
|
||
size_int (precision - size), 0);
|
||
newconst = fold (build (BIT_AND_EXPR,
|
||
TREE_TYPE (varop), newconst,
|
||
convert (TREE_TYPE (varop),
|
||
mask)));
|
||
}
|
||
|
||
|
||
t = build (code, type, TREE_OPERAND (t, 0),
|
||
TREE_OPERAND (t, 1));
|
||
TREE_OPERAND (t, constopnum) = newconst;
|
||
return t;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Change X >= CST to X > (CST - 1) if CST is positive. */
|
||
if (TREE_CODE (arg1) == INTEGER_CST
|
||
&& TREE_CODE (arg0) != INTEGER_CST
|
||
&& tree_int_cst_sgn (arg1) > 0)
|
||
{
|
||
switch (TREE_CODE (t))
|
||
{
|
||
case GE_EXPR:
|
||
code = GT_EXPR;
|
||
arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
|
||
t = build (code, type, TREE_OPERAND (t, 0), arg1);
|
||
break;
|
||
|
||
case LT_EXPR:
|
||
code = LE_EXPR;
|
||
arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
|
||
t = build (code, type, TREE_OPERAND (t, 0), arg1);
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* If this is an EQ or NE comparison with zero and ARG0 is
|
||
(1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
|
||
two operations, but the latter can be done in one less insn
|
||
on machines that have only two-operand insns or on which a
|
||
constant cannot be the first operand. */
|
||
if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
|
||
&& TREE_CODE (arg0) == BIT_AND_EXPR)
|
||
{
|
||
if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR
|
||
&& integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0)))
|
||
return
|
||
fold (build (code, type,
|
||
build (BIT_AND_EXPR, TREE_TYPE (arg0),
|
||
build (RSHIFT_EXPR,
|
||
TREE_TYPE (TREE_OPERAND (arg0, 0)),
|
||
TREE_OPERAND (arg0, 1),
|
||
TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)),
|
||
convert (TREE_TYPE (arg0),
|
||
integer_one_node)),
|
||
arg1));
|
||
else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
|
||
&& integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
|
||
return
|
||
fold (build (code, type,
|
||
build (BIT_AND_EXPR, TREE_TYPE (arg0),
|
||
build (RSHIFT_EXPR,
|
||
TREE_TYPE (TREE_OPERAND (arg0, 1)),
|
||
TREE_OPERAND (arg0, 0),
|
||
TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)),
|
||
convert (TREE_TYPE (arg0),
|
||
integer_one_node)),
|
||
arg1));
|
||
}
|
||
|
||
/* If this is an NE or EQ comparison of zero against the result of a
|
||
signed MOD operation whose second operand is a power of 2, make
|
||
the MOD operation unsigned since it is simpler and equivalent. */
|
||
if ((code == NE_EXPR || code == EQ_EXPR)
|
||
&& integer_zerop (arg1)
|
||
&& ! TREE_UNSIGNED (TREE_TYPE (arg0))
|
||
&& (TREE_CODE (arg0) == TRUNC_MOD_EXPR
|
||
|| TREE_CODE (arg0) == CEIL_MOD_EXPR
|
||
|| TREE_CODE (arg0) == FLOOR_MOD_EXPR
|
||
|| TREE_CODE (arg0) == ROUND_MOD_EXPR)
|
||
&& integer_pow2p (TREE_OPERAND (arg0, 1)))
|
||
{
|
||
tree newtype = unsigned_type (TREE_TYPE (arg0));
|
||
tree newmod = build (TREE_CODE (arg0), newtype,
|
||
convert (newtype, TREE_OPERAND (arg0, 0)),
|
||
convert (newtype, TREE_OPERAND (arg0, 1)));
|
||
|
||
return build (code, type, newmod, convert (newtype, arg1));
|
||
}
|
||
|
||
/* If this is an NE comparison of zero with an AND of one, remove the
|
||
comparison since the AND will give the correct value. */
|
||
if (code == NE_EXPR && integer_zerop (arg1)
|
||
&& TREE_CODE (arg0) == BIT_AND_EXPR
|
||
&& integer_onep (TREE_OPERAND (arg0, 1)))
|
||
return convert (type, arg0);
|
||
|
||
/* If we have (A & C) == C where C is a power of 2, convert this into
|
||
(A & C) != 0. Similarly for NE_EXPR. */
|
||
if ((code == EQ_EXPR || code == NE_EXPR)
|
||
&& TREE_CODE (arg0) == BIT_AND_EXPR
|
||
&& integer_pow2p (TREE_OPERAND (arg0, 1))
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
|
||
return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
|
||
arg0, integer_zero_node);
|
||
|
||
/* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
|
||
and similarly for >= into !=. */
|
||
if ((code == LT_EXPR || code == GE_EXPR)
|
||
&& TREE_UNSIGNED (TREE_TYPE (arg0))
|
||
&& TREE_CODE (arg1) == LSHIFT_EXPR
|
||
&& integer_onep (TREE_OPERAND (arg1, 0)))
|
||
return build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
|
||
build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
|
||
TREE_OPERAND (arg1, 1)),
|
||
convert (TREE_TYPE (arg0), integer_zero_node));
|
||
|
||
else if ((code == LT_EXPR || code == GE_EXPR)
|
||
&& TREE_UNSIGNED (TREE_TYPE (arg0))
|
||
&& (TREE_CODE (arg1) == NOP_EXPR
|
||
|| TREE_CODE (arg1) == CONVERT_EXPR)
|
||
&& TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR
|
||
&& integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0)))
|
||
return
|
||
build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
|
||
convert (TREE_TYPE (arg0),
|
||
build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
|
||
TREE_OPERAND (TREE_OPERAND (arg1, 0), 1))),
|
||
convert (TREE_TYPE (arg0), integer_zero_node));
|
||
|
||
/* Simplify comparison of something with itself. (For IEEE
|
||
floating-point, we can only do some of these simplifications.) */
|
||
if (operand_equal_p (arg0, arg1, 0))
|
||
{
|
||
switch (code)
|
||
{
|
||
case EQ_EXPR:
|
||
case GE_EXPR:
|
||
case LE_EXPR:
|
||
if (INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
|
||
return constant_boolean_node (1, type);
|
||
code = EQ_EXPR;
|
||
TREE_SET_CODE (t, code);
|
||
break;
|
||
|
||
case NE_EXPR:
|
||
/* For NE, we can only do this simplification if integer. */
|
||
if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
|
||
break;
|
||
/* ... fall through ... */
|
||
case GT_EXPR:
|
||
case LT_EXPR:
|
||
return constant_boolean_node (0, type);
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
|
||
/* An unsigned comparison against 0 can be simplified. */
|
||
if (integer_zerop (arg1)
|
||
&& (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
|
||
|| POINTER_TYPE_P (TREE_TYPE (arg1)))
|
||
&& TREE_UNSIGNED (TREE_TYPE (arg1)))
|
||
{
|
||
switch (TREE_CODE (t))
|
||
{
|
||
case GT_EXPR:
|
||
code = NE_EXPR;
|
||
TREE_SET_CODE (t, NE_EXPR);
|
||
break;
|
||
case LE_EXPR:
|
||
code = EQ_EXPR;
|
||
TREE_SET_CODE (t, EQ_EXPR);
|
||
break;
|
||
case GE_EXPR:
|
||
return omit_one_operand (type,
|
||
convert (type, integer_one_node),
|
||
arg0);
|
||
case LT_EXPR:
|
||
return omit_one_operand (type,
|
||
convert (type, integer_zero_node),
|
||
arg0);
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* An unsigned <= 0x7fffffff can be simplified. */
|
||
{
|
||
int width = TYPE_PRECISION (TREE_TYPE (arg1));
|
||
if (TREE_CODE (arg1) == INTEGER_CST
|
||
&& ! TREE_CONSTANT_OVERFLOW (arg1)
|
||
&& width <= HOST_BITS_PER_WIDE_INT
|
||
&& TREE_INT_CST_LOW (arg1) == ((HOST_WIDE_INT) 1 << (width - 1)) - 1
|
||
&& TREE_INT_CST_HIGH (arg1) == 0
|
||
&& (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
|
||
|| POINTER_TYPE_P (TREE_TYPE (arg1)))
|
||
&& TREE_UNSIGNED (TREE_TYPE (arg1)))
|
||
{
|
||
switch (TREE_CODE (t))
|
||
{
|
||
case LE_EXPR:
|
||
return fold (build (GE_EXPR, type,
|
||
convert (signed_type (TREE_TYPE (arg0)),
|
||
arg0),
|
||
convert (signed_type (TREE_TYPE (arg1)),
|
||
integer_zero_node)));
|
||
case GT_EXPR:
|
||
return fold (build (LT_EXPR, type,
|
||
convert (signed_type (TREE_TYPE (arg0)),
|
||
arg0),
|
||
convert (signed_type (TREE_TYPE (arg1)),
|
||
integer_zero_node)));
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* If we are comparing an expression that just has comparisons
|
||
of two integer values, arithmetic expressions of those comparisons,
|
||
and constants, we can simplify it. There are only three cases
|
||
to check: the two values can either be equal, the first can be
|
||
greater, or the second can be greater. Fold the expression for
|
||
those three values. Since each value must be 0 or 1, we have
|
||
eight possibilities, each of which corresponds to the constant 0
|
||
or 1 or one of the six possible comparisons.
|
||
|
||
This handles common cases like (a > b) == 0 but also handles
|
||
expressions like ((x > y) - (y > x)) > 0, which supposedly
|
||
occur in macroized code. */
|
||
|
||
if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
|
||
{
|
||
tree cval1 = 0, cval2 = 0;
|
||
int save_p = 0;
|
||
|
||
if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p)
|
||
/* Don't handle degenerate cases here; they should already
|
||
have been handled anyway. */
|
||
&& cval1 != 0 && cval2 != 0
|
||
&& ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
|
||
&& TREE_TYPE (cval1) == TREE_TYPE (cval2)
|
||
&& INTEGRAL_TYPE_P (TREE_TYPE (cval1))
|
||
&& TYPE_MAX_VALUE (TREE_TYPE (cval1))
|
||
&& TYPE_MAX_VALUE (TREE_TYPE (cval2))
|
||
&& ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
|
||
TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
|
||
{
|
||
tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
|
||
tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
|
||
|
||
/* We can't just pass T to eval_subst in case cval1 or cval2
|
||
was the same as ARG1. */
|
||
|
||
tree high_result
|
||
= fold (build (code, type,
|
||
eval_subst (arg0, cval1, maxval, cval2, minval),
|
||
arg1));
|
||
tree equal_result
|
||
= fold (build (code, type,
|
||
eval_subst (arg0, cval1, maxval, cval2, maxval),
|
||
arg1));
|
||
tree low_result
|
||
= fold (build (code, type,
|
||
eval_subst (arg0, cval1, minval, cval2, maxval),
|
||
arg1));
|
||
|
||
/* All three of these results should be 0 or 1. Confirm they
|
||
are. Then use those values to select the proper code
|
||
to use. */
|
||
|
||
if ((integer_zerop (high_result)
|
||
|| integer_onep (high_result))
|
||
&& (integer_zerop (equal_result)
|
||
|| integer_onep (equal_result))
|
||
&& (integer_zerop (low_result)
|
||
|| integer_onep (low_result)))
|
||
{
|
||
/* Make a 3-bit mask with the high-order bit being the
|
||
value for `>', the next for '=', and the low for '<'. */
|
||
switch ((integer_onep (high_result) * 4)
|
||
+ (integer_onep (equal_result) * 2)
|
||
+ integer_onep (low_result))
|
||
{
|
||
case 0:
|
||
/* Always false. */
|
||
return omit_one_operand (type, integer_zero_node, arg0);
|
||
case 1:
|
||
code = LT_EXPR;
|
||
break;
|
||
case 2:
|
||
code = EQ_EXPR;
|
||
break;
|
||
case 3:
|
||
code = LE_EXPR;
|
||
break;
|
||
case 4:
|
||
code = GT_EXPR;
|
||
break;
|
||
case 5:
|
||
code = NE_EXPR;
|
||
break;
|
||
case 6:
|
||
code = GE_EXPR;
|
||
break;
|
||
case 7:
|
||
/* Always true. */
|
||
return omit_one_operand (type, integer_one_node, arg0);
|
||
}
|
||
|
||
t = build (code, type, cval1, cval2);
|
||
if (save_p)
|
||
return save_expr (t);
|
||
else
|
||
return fold (t);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* If this is a comparison of a field, we may be able to simplify it. */
|
||
if ((TREE_CODE (arg0) == COMPONENT_REF
|
||
|| TREE_CODE (arg0) == BIT_FIELD_REF)
|
||
&& (code == EQ_EXPR || code == NE_EXPR)
|
||
/* Handle the constant case even without -O
|
||
to make sure the warnings are given. */
|
||
&& (optimize || TREE_CODE (arg1) == INTEGER_CST))
|
||
{
|
||
t1 = optimize_bit_field_compare (code, type, arg0, arg1);
|
||
return t1 ? t1 : t;
|
||
}
|
||
|
||
/* If this is a comparison of complex values and either or both sides
|
||
are a COMPLEX_EXPR or COMPLEX_CST, it is best to split up the
|
||
comparisons and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR.
|
||
This may prevent needless evaluations. */
|
||
if ((code == EQ_EXPR || code == NE_EXPR)
|
||
&& TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
|
||
&& (TREE_CODE (arg0) == COMPLEX_EXPR
|
||
|| TREE_CODE (arg1) == COMPLEX_EXPR
|
||
|| TREE_CODE (arg0) == COMPLEX_CST
|
||
|| TREE_CODE (arg1) == COMPLEX_CST))
|
||
{
|
||
tree subtype = TREE_TYPE (TREE_TYPE (arg0));
|
||
tree real0, imag0, real1, imag1;
|
||
|
||
arg0 = save_expr (arg0);
|
||
arg1 = save_expr (arg1);
|
||
real0 = fold (build1 (REALPART_EXPR, subtype, arg0));
|
||
imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0));
|
||
real1 = fold (build1 (REALPART_EXPR, subtype, arg1));
|
||
imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1));
|
||
|
||
return fold (build ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR
|
||
: TRUTH_ORIF_EXPR),
|
||
type,
|
||
fold (build (code, type, real0, real1)),
|
||
fold (build (code, type, imag0, imag1))));
|
||
}
|
||
|
||
/* From here on, the only cases we handle are when the result is
|
||
known to be a constant.
|
||
|
||
To compute GT, swap the arguments and do LT.
|
||
To compute GE, do LT and invert the result.
|
||
To compute LE, swap the arguments, do LT and invert the result.
|
||
To compute NE, do EQ and invert the result.
|
||
|
||
Therefore, the code below must handle only EQ and LT. */
|
||
|
||
if (code == LE_EXPR || code == GT_EXPR)
|
||
{
|
||
tem = arg0, arg0 = arg1, arg1 = tem;
|
||
code = swap_tree_comparison (code);
|
||
}
|
||
|
||
/* Note that it is safe to invert for real values here because we
|
||
will check below in the one case that it matters. */
|
||
|
||
invert = 0;
|
||
if (code == NE_EXPR || code == GE_EXPR)
|
||
{
|
||
invert = 1;
|
||
code = invert_tree_comparison (code);
|
||
}
|
||
|
||
/* Compute a result for LT or EQ if args permit;
|
||
otherwise return T. */
|
||
if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
|
||
{
|
||
if (code == EQ_EXPR)
|
||
t1 = build_int_2 ((TREE_INT_CST_LOW (arg0)
|
||
== TREE_INT_CST_LOW (arg1))
|
||
&& (TREE_INT_CST_HIGH (arg0)
|
||
== TREE_INT_CST_HIGH (arg1)),
|
||
0);
|
||
else
|
||
t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0))
|
||
? INT_CST_LT_UNSIGNED (arg0, arg1)
|
||
: INT_CST_LT (arg0, arg1)),
|
||
0);
|
||
}
|
||
|
||
#if 0 /* This is no longer useful, but breaks some real code. */
|
||
/* Assume a nonexplicit constant cannot equal an explicit one,
|
||
since such code would be undefined anyway.
|
||
Exception: on sysvr4, using #pragma weak,
|
||
a label can come out as 0. */
|
||
else if (TREE_CODE (arg1) == INTEGER_CST
|
||
&& !integer_zerop (arg1)
|
||
&& TREE_CONSTANT (arg0)
|
||
&& TREE_CODE (arg0) == ADDR_EXPR
|
||
&& code == EQ_EXPR)
|
||
t1 = build_int_2 (0, 0);
|
||
#endif
|
||
/* Two real constants can be compared explicitly. */
|
||
else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
|
||
{
|
||
/* If either operand is a NaN, the result is false with two
|
||
exceptions: First, an NE_EXPR is true on NaNs, but that case
|
||
is already handled correctly since we will be inverting the
|
||
result for NE_EXPR. Second, if we had inverted a LE_EXPR
|
||
or a GE_EXPR into a LT_EXPR, we must return true so that it
|
||
will be inverted into false. */
|
||
|
||
if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
|
||
|| REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
|
||
t1 = build_int_2 (invert && code == LT_EXPR, 0);
|
||
|
||
else if (code == EQ_EXPR)
|
||
t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
|
||
TREE_REAL_CST (arg1)),
|
||
0);
|
||
else
|
||
t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0),
|
||
TREE_REAL_CST (arg1)),
|
||
0);
|
||
}
|
||
|
||
if (t1 == NULL_TREE)
|
||
return t;
|
||
|
||
if (invert)
|
||
TREE_INT_CST_LOW (t1) ^= 1;
|
||
|
||
TREE_TYPE (t1) = type;
|
||
if (TREE_CODE (type) == BOOLEAN_TYPE)
|
||
return truthvalue_conversion (t1);
|
||
return t1;
|
||
|
||
case COND_EXPR:
|
||
/* Pedantic ANSI C says that a conditional expression is never an lvalue,
|
||
so all simple results must be passed through pedantic_non_lvalue. */
|
||
if (TREE_CODE (arg0) == INTEGER_CST)
|
||
return pedantic_non_lvalue
|
||
(TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)));
|
||
else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
|
||
return pedantic_omit_one_operand (type, arg1, arg0);
|
||
|
||
/* If the second operand is zero, invert the comparison and swap
|
||
the second and third operands. Likewise if the second operand
|
||
is constant and the third is not or if the third operand is
|
||
equivalent to the first operand of the comparison. */
|
||
|
||
if (integer_zerop (arg1)
|
||
|| (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2)))
|
||
|| (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
|
||
&& operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
|
||
TREE_OPERAND (t, 2),
|
||
TREE_OPERAND (arg0, 1))))
|
||
{
|
||
/* See if this can be inverted. If it can't, possibly because
|
||
it was a floating-point inequality comparison, don't do
|
||
anything. */
|
||
tem = invert_truthvalue (arg0);
|
||
|
||
if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
|
||
{
|
||
t = build (code, type, tem,
|
||
TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
|
||
arg0 = tem;
|
||
arg1 = TREE_OPERAND (t, 2);
|
||
STRIP_NOPS (arg1);
|
||
}
|
||
}
|
||
|
||
/* If we have A op B ? A : C, we may be able to convert this to a
|
||
simpler expression, depending on the operation and the values
|
||
of B and C. IEEE floating point prevents this though,
|
||
because A or B might be -0.0 or a NaN. */
|
||
|
||
if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
|
||
&& (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
|
||
|| ! FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0)))
|
||
|| flag_fast_math)
|
||
&& operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
|
||
arg1, TREE_OPERAND (arg0, 1)))
|
||
{
|
||
tree arg2 = TREE_OPERAND (t, 2);
|
||
enum tree_code comp_code = TREE_CODE (arg0);
|
||
|
||
STRIP_NOPS (arg2);
|
||
|
||
/* If we have A op 0 ? A : -A, this is A, -A, abs (A), or abs (-A),
|
||
depending on the comparison operation. */
|
||
if ((FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 1)))
|
||
? real_zerop (TREE_OPERAND (arg0, 1))
|
||
: integer_zerop (TREE_OPERAND (arg0, 1)))
|
||
&& TREE_CODE (arg2) == NEGATE_EXPR
|
||
&& operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0))
|
||
switch (comp_code)
|
||
{
|
||
case EQ_EXPR:
|
||
return pedantic_non_lvalue
|
||
(fold (build1 (NEGATE_EXPR, type, arg1)));
|
||
case NE_EXPR:
|
||
return pedantic_non_lvalue (convert (type, arg1));
|
||
case GE_EXPR:
|
||
case GT_EXPR:
|
||
return pedantic_non_lvalue
|
||
(convert (type, fold (build1 (ABS_EXPR,
|
||
TREE_TYPE (arg1), arg1))));
|
||
case LE_EXPR:
|
||
case LT_EXPR:
|
||
return pedantic_non_lvalue
|
||
(fold (build1 (NEGATE_EXPR, type,
|
||
convert (type,
|
||
fold (build1 (ABS_EXPR,
|
||
TREE_TYPE (arg1),
|
||
arg1))))));
|
||
default:
|
||
abort ();
|
||
}
|
||
|
||
/* If this is A != 0 ? A : 0, this is simply A. For ==, it is
|
||
always zero. */
|
||
|
||
if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
|
||
{
|
||
if (comp_code == NE_EXPR)
|
||
return pedantic_non_lvalue (convert (type, arg1));
|
||
else if (comp_code == EQ_EXPR)
|
||
return pedantic_non_lvalue (convert (type, integer_zero_node));
|
||
}
|
||
|
||
/* If this is A op B ? A : B, this is either A, B, min (A, B),
|
||
or max (A, B), depending on the operation. */
|
||
|
||
if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1),
|
||
arg2, TREE_OPERAND (arg0, 0)))
|
||
{
|
||
tree comp_op0 = TREE_OPERAND (arg0, 0);
|
||
tree comp_op1 = TREE_OPERAND (arg0, 1);
|
||
tree comp_type = TREE_TYPE (comp_op0);
|
||
|
||
switch (comp_code)
|
||
{
|
||
case EQ_EXPR:
|
||
return pedantic_non_lvalue (convert (type, arg2));
|
||
case NE_EXPR:
|
||
return pedantic_non_lvalue (convert (type, arg1));
|
||
case LE_EXPR:
|
||
case LT_EXPR:
|
||
/* In C++ a ?: expression can be an lvalue, so put the
|
||
operand which will be used if they are equal first
|
||
so that we can convert this back to the
|
||
corresponding COND_EXPR. */
|
||
return pedantic_non_lvalue
|
||
(convert (type, (fold (build (MIN_EXPR, comp_type,
|
||
(comp_code == LE_EXPR
|
||
? comp_op0 : comp_op1),
|
||
(comp_code == LE_EXPR
|
||
? comp_op1 : comp_op0))))));
|
||
break;
|
||
case GE_EXPR:
|
||
case GT_EXPR:
|
||
return pedantic_non_lvalue
|
||
(convert (type, fold (build (MAX_EXPR, comp_type,
|
||
(comp_code == GE_EXPR
|
||
? comp_op0 : comp_op1),
|
||
(comp_code == GE_EXPR
|
||
? comp_op1 : comp_op0)))));
|
||
break;
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
|
||
/* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
|
||
we might still be able to simplify this. For example,
|
||
if C1 is one less or one more than C2, this might have started
|
||
out as a MIN or MAX and been transformed by this function.
|
||
Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
|
||
|
||
if (INTEGRAL_TYPE_P (type)
|
||
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
|
||
&& TREE_CODE (arg2) == INTEGER_CST)
|
||
switch (comp_code)
|
||
{
|
||
case EQ_EXPR:
|
||
/* We can replace A with C1 in this case. */
|
||
arg1 = convert (type, TREE_OPERAND (arg0, 1));
|
||
t = build (code, type, TREE_OPERAND (t, 0), arg1,
|
||
TREE_OPERAND (t, 2));
|
||
break;
|
||
|
||
case LT_EXPR:
|
||
/* If C1 is C2 + 1, this is min(A, C2). */
|
||
if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 1),
|
||
const_binop (PLUS_EXPR, arg2,
|
||
integer_one_node, 0), 1))
|
||
return pedantic_non_lvalue
|
||
(fold (build (MIN_EXPR, type, arg1, arg2)));
|
||
break;
|
||
|
||
case LE_EXPR:
|
||
/* If C1 is C2 - 1, this is min(A, C2). */
|
||
if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 1),
|
||
const_binop (MINUS_EXPR, arg2,
|
||
integer_one_node, 0), 1))
|
||
return pedantic_non_lvalue
|
||
(fold (build (MIN_EXPR, type, arg1, arg2)));
|
||
break;
|
||
|
||
case GT_EXPR:
|
||
/* If C1 is C2 - 1, this is max(A, C2). */
|
||
if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 1),
|
||
const_binop (MINUS_EXPR, arg2,
|
||
integer_one_node, 0), 1))
|
||
return pedantic_non_lvalue
|
||
(fold (build (MAX_EXPR, type, arg1, arg2)));
|
||
break;
|
||
|
||
case GE_EXPR:
|
||
/* If C1 is C2 + 1, this is max(A, C2). */
|
||
if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
|
||
&& operand_equal_p (TREE_OPERAND (arg0, 1),
|
||
const_binop (PLUS_EXPR, arg2,
|
||
integer_one_node, 0), 1))
|
||
return pedantic_non_lvalue
|
||
(fold (build (MAX_EXPR, type, arg1, arg2)));
|
||
break;
|
||
case NE_EXPR:
|
||
break;
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
|
||
/* If the second operand is simpler than the third, swap them
|
||
since that produces better jump optimization results. */
|
||
if ((TREE_CONSTANT (arg1) || TREE_CODE_CLASS (TREE_CODE (arg1)) == 'd'
|
||
|| TREE_CODE (arg1) == SAVE_EXPR)
|
||
&& ! (TREE_CONSTANT (TREE_OPERAND (t, 2))
|
||
|| TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (t, 2))) == 'd'
|
||
|| TREE_CODE (TREE_OPERAND (t, 2)) == SAVE_EXPR))
|
||
{
|
||
/* See if this can be inverted. If it can't, possibly because
|
||
it was a floating-point inequality comparison, don't do
|
||
anything. */
|
||
tem = invert_truthvalue (arg0);
|
||
|
||
if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
|
||
{
|
||
t = build (code, type, tem,
|
||
TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
|
||
arg0 = tem;
|
||
arg1 = TREE_OPERAND (t, 2);
|
||
STRIP_NOPS (arg1);
|
||
}
|
||
}
|
||
|
||
/* Convert A ? 1 : 0 to simply A. */
|
||
if (integer_onep (TREE_OPERAND (t, 1))
|
||
&& integer_zerop (TREE_OPERAND (t, 2))
|
||
/* If we try to convert TREE_OPERAND (t, 0) to our type, the
|
||
call to fold will try to move the conversion inside
|
||
a COND, which will recurse. In that case, the COND_EXPR
|
||
is probably the best choice, so leave it alone. */
|
||
&& type == TREE_TYPE (arg0))
|
||
return pedantic_non_lvalue (arg0);
|
||
|
||
/* Look for expressions of the form A & 2 ? 2 : 0. The result of this
|
||
operation is simply A & 2. */
|
||
|
||
if (integer_zerop (TREE_OPERAND (t, 2))
|
||
&& TREE_CODE (arg0) == NE_EXPR
|
||
&& integer_zerop (TREE_OPERAND (arg0, 1))
|
||
&& integer_pow2p (arg1)
|
||
&& TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
|
||
&& operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
|
||
arg1, 1))
|
||
return pedantic_non_lvalue (convert (type, TREE_OPERAND (arg0, 0)));
|
||
|
||
return t;
|
||
|
||
case COMPOUND_EXPR:
|
||
/* When pedantic, a compound expression can be neither an lvalue
|
||
nor an integer constant expression. */
|
||
if (TREE_SIDE_EFFECTS (arg0) || pedantic)
|
||
return t;
|
||
/* Don't let (0, 0) be null pointer constant. */
|
||
if (integer_zerop (arg1))
|
||
return non_lvalue (arg1);
|
||
return arg1;
|
||
|
||
case COMPLEX_EXPR:
|
||
if (wins)
|
||
return build_complex (type, arg0, arg1);
|
||
return t;
|
||
|
||
case REALPART_EXPR:
|
||
if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
|
||
return t;
|
||
else if (TREE_CODE (arg0) == COMPLEX_EXPR)
|
||
return omit_one_operand (type, TREE_OPERAND (arg0, 0),
|
||
TREE_OPERAND (arg0, 1));
|
||
else if (TREE_CODE (arg0) == COMPLEX_CST)
|
||
return TREE_REALPART (arg0);
|
||
else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
|
||
return fold (build (TREE_CODE (arg0), type,
|
||
fold (build1 (REALPART_EXPR, type,
|
||
TREE_OPERAND (arg0, 0))),
|
||
fold (build1 (REALPART_EXPR,
|
||
type, TREE_OPERAND (arg0, 1)))));
|
||
return t;
|
||
|
||
case IMAGPART_EXPR:
|
||
if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
|
||
return convert (type, integer_zero_node);
|
||
else if (TREE_CODE (arg0) == COMPLEX_EXPR)
|
||
return omit_one_operand (type, TREE_OPERAND (arg0, 1),
|
||
TREE_OPERAND (arg0, 0));
|
||
else if (TREE_CODE (arg0) == COMPLEX_CST)
|
||
return TREE_IMAGPART (arg0);
|
||
else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
|
||
return fold (build (TREE_CODE (arg0), type,
|
||
fold (build1 (IMAGPART_EXPR, type,
|
||
TREE_OPERAND (arg0, 0))),
|
||
fold (build1 (IMAGPART_EXPR, type,
|
||
TREE_OPERAND (arg0, 1)))));
|
||
return t;
|
||
|
||
/* Pull arithmetic ops out of the CLEANUP_POINT_EXPR where
|
||
appropriate. */
|
||
case CLEANUP_POINT_EXPR:
|
||
if (! has_cleanups (arg0))
|
||
return TREE_OPERAND (t, 0);
|
||
|
||
{
|
||
enum tree_code code0 = TREE_CODE (arg0);
|
||
int kind0 = TREE_CODE_CLASS (code0);
|
||
tree arg00 = TREE_OPERAND (arg0, 0);
|
||
tree arg01;
|
||
|
||
if (kind0 == '1' || code0 == TRUTH_NOT_EXPR)
|
||
return fold (build1 (code0, type,
|
||
fold (build1 (CLEANUP_POINT_EXPR,
|
||
TREE_TYPE (arg00), arg00))));
|
||
|
||
if (kind0 == '<' || kind0 == '2'
|
||
|| code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR
|
||
|| code0 == TRUTH_AND_EXPR || code0 == TRUTH_OR_EXPR
|
||
|| code0 == TRUTH_XOR_EXPR)
|
||
{
|
||
arg01 = TREE_OPERAND (arg0, 1);
|
||
|
||
if (TREE_CONSTANT (arg00)
|
||
|| ((code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR)
|
||
&& ! has_cleanups (arg00)))
|
||
return fold (build (code0, type, arg00,
|
||
fold (build1 (CLEANUP_POINT_EXPR,
|
||
TREE_TYPE (arg01), arg01))));
|
||
|
||
if (TREE_CONSTANT (arg01))
|
||
return fold (build (code0, type,
|
||
fold (build1 (CLEANUP_POINT_EXPR,
|
||
TREE_TYPE (arg00), arg00)),
|
||
arg01));
|
||
}
|
||
|
||
return t;
|
||
}
|
||
|
||
default:
|
||
return t;
|
||
} /* switch (code) */
|
||
}
|
||
|
||
/* Determine if first argument is a multiple of second argument.
|
||
Return 0 if it is not, or is not easily determined to so be.
|
||
|
||
An example of the sort of thing we care about (at this point --
|
||
this routine could surely be made more general, and expanded
|
||
to do what the *_DIV_EXPR's fold() cases do now) is discovering
|
||
that
|
||
|
||
SAVE_EXPR (I) * SAVE_EXPR (J * 8)
|
||
|
||
is a multiple of
|
||
|
||
SAVE_EXPR (J * 8)
|
||
|
||
when we know that the two `SAVE_EXPR (J * 8)' nodes are the
|
||
same node (which means they will have the same value at run
|
||
time, even though we don't know when they'll be assigned).
|
||
|
||
This code also handles discovering that
|
||
|
||
SAVE_EXPR (I) * SAVE_EXPR (J * 8)
|
||
|
||
is a multiple of
|
||
|
||
8
|
||
|
||
(of course) so we don't have to worry about dealing with a
|
||
possible remainder.
|
||
|
||
Note that we _look_ inside a SAVE_EXPR only to determine
|
||
how it was calculated; it is not safe for fold() to do much
|
||
of anything else with the internals of a SAVE_EXPR, since
|
||
fold() cannot know when it will be evaluated at run time.
|
||
For example, the latter example above _cannot_ be implemented
|
||
as
|
||
|
||
SAVE_EXPR (I) * J
|
||
|
||
or any variant thereof, since the value of J at evaluation time
|
||
of the original SAVE_EXPR is not necessarily the same at the time
|
||
the new expression is evaluated. The only optimization of this
|
||
sort that would be valid is changing
|
||
|
||
SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
|
||
divided by
|
||
8
|
||
|
||
to
|
||
|
||
SAVE_EXPR (I) * SAVE_EXPR (J)
|
||
|
||
(where the same SAVE_EXPR (J) is used in the original and the
|
||
transformed version). */
|
||
|
||
static int
|
||
multiple_of_p (type, top, bottom)
|
||
tree type;
|
||
tree top;
|
||
tree bottom;
|
||
{
|
||
if (operand_equal_p (top, bottom, 0))
|
||
return 1;
|
||
|
||
if (TREE_CODE (type) != INTEGER_TYPE)
|
||
return 0;
|
||
|
||
switch (TREE_CODE (top))
|
||
{
|
||
case MULT_EXPR:
|
||
return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
|
||
|| multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
|
||
|
||
case PLUS_EXPR:
|
||
case MINUS_EXPR:
|
||
return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
|
||
&& multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
|
||
|
||
case NOP_EXPR:
|
||
/* Punt if conversion from non-integral or wider integral type. */
|
||
if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE)
|
||
|| (TYPE_PRECISION (type)
|
||
< TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (top, 0)))))
|
||
return 0;
|
||
/* Fall through. */
|
||
case SAVE_EXPR:
|
||
return multiple_of_p (type, TREE_OPERAND (top, 0), bottom);
|
||
|
||
case INTEGER_CST:
|
||
if ((TREE_CODE (bottom) != INTEGER_CST)
|
||
|| (tree_int_cst_sgn (top) < 0)
|
||
|| (tree_int_cst_sgn (bottom) < 0))
|
||
return 0;
|
||
return integer_zerop (const_binop (TRUNC_MOD_EXPR,
|
||
top, bottom, 0));
|
||
|
||
default:
|
||
return 0;
|
||
}
|
||
}
|
||
|