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1543 lines
47 KiB
C
1543 lines
47 KiB
C
/* Perform branch target register load optimizations.
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Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
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Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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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 GCC; see the file COPYING. If not, write to the Free
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Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301, USA. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "rtl.h"
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#include "hard-reg-set.h"
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#include "regs.h"
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#include "fibheap.h"
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#include "output.h"
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#include "target.h"
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#include "expr.h"
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#include "flags.h"
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#include "insn-attr.h"
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#include "function.h"
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#include "except.h"
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#include "tm_p.h"
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#include "toplev.h"
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#include "tree-pass.h"
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/* Target register optimizations - these are performed after reload. */
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typedef struct btr_def_group_s
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{
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struct btr_def_group_s *next;
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rtx src;
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struct btr_def_s *members;
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} *btr_def_group;
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typedef struct btr_user_s
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{
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struct btr_user_s *next;
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basic_block bb;
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int luid;
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rtx insn;
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/* If INSN has a single use of a single branch register, then
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USE points to it within INSN. If there is more than
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one branch register use, or the use is in some way ambiguous,
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then USE is NULL. */
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rtx use;
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int n_reaching_defs;
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int first_reaching_def;
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char other_use_this_block;
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} *btr_user;
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/* btr_def structs appear on three lists:
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1. A list of all btr_def structures (head is
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ALL_BTR_DEFS, linked by the NEXT field).
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2. A list of branch reg definitions per basic block (head is
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BB_BTR_DEFS[i], linked by the NEXT_THIS_BB field).
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3. A list of all branch reg definitions belonging to the same
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group (head is in a BTR_DEF_GROUP struct, linked by
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NEXT_THIS_GROUP field). */
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typedef struct btr_def_s
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{
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struct btr_def_s *next_this_bb;
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struct btr_def_s *next_this_group;
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basic_block bb;
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int luid;
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rtx insn;
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int btr;
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int cost;
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/* For a branch register setting insn that has a constant
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source (i.e. a label), group links together all the
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insns with the same source. For other branch register
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setting insns, group is NULL. */
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btr_def_group group;
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btr_user uses;
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/* If this def has a reaching use which is not a simple use
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in a branch instruction, then has_ambiguous_use will be true,
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and we will not attempt to migrate this definition. */
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char has_ambiguous_use;
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/* live_range is an approximation to the true live range for this
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def/use web, because it records the set of blocks that contain
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the live range. There could be other live ranges for the same
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branch register in that set of blocks, either in the block
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containing the def (before the def), or in a block containing
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a use (after the use). If there are such other live ranges, then
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other_btr_uses_before_def or other_btr_uses_after_use must be set true
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as appropriate. */
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char other_btr_uses_before_def;
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char other_btr_uses_after_use;
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/* We set own_end when we have moved a definition into a dominator.
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Thus, when a later combination removes this definition again, we know
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to clear out trs_live_at_end again. */
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char own_end;
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bitmap live_range;
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} *btr_def;
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static int issue_rate;
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static int basic_block_freq (basic_block);
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static int insn_sets_btr_p (rtx, int, int *);
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static rtx *find_btr_use (rtx);
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static int btr_referenced_p (rtx, rtx *);
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static int find_btr_reference (rtx *, void *);
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static void find_btr_def_group (btr_def_group *, btr_def);
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static btr_def add_btr_def (fibheap_t, basic_block, int, rtx,
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unsigned int, int, btr_def_group *);
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static btr_user new_btr_user (basic_block, int, rtx);
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static void dump_hard_reg_set (HARD_REG_SET);
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static void dump_btrs_live (int);
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static void note_other_use_this_block (unsigned int, btr_user);
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static void compute_defs_uses_and_gen (fibheap_t, btr_def *,btr_user *,
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sbitmap *, sbitmap *, HARD_REG_SET *);
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static void compute_kill (sbitmap *, sbitmap *, HARD_REG_SET *);
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static void compute_out (sbitmap *bb_out, sbitmap *, sbitmap *, int);
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static void link_btr_uses (btr_def *, btr_user *, sbitmap *, sbitmap *, int);
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static void build_btr_def_use_webs (fibheap_t);
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static int block_at_edge_of_live_range_p (int, btr_def);
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static void clear_btr_from_live_range (btr_def def);
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static void add_btr_to_live_range (btr_def, int);
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static void augment_live_range (bitmap, HARD_REG_SET *, basic_block,
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basic_block, int);
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static int choose_btr (HARD_REG_SET);
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static void combine_btr_defs (btr_def, HARD_REG_SET *);
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static void btr_def_live_range (btr_def, HARD_REG_SET *);
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static void move_btr_def (basic_block, int, btr_def, bitmap, HARD_REG_SET *);
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static int migrate_btr_def (btr_def, int);
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static void migrate_btr_defs (enum reg_class, int);
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static int can_move_up (basic_block, rtx, int);
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static void note_btr_set (rtx, rtx, void *);
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/* The following code performs code motion of target load instructions
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(instructions that set branch target registers), to move them
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forward away from the branch instructions and out of loops (or,
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more generally, from a more frequently executed place to a less
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frequently executed place).
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Moving target load instructions further in front of the branch
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instruction that uses the target register value means that the hardware
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has a better chance of preloading the instructions at the branch
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target by the time the branch is reached. This avoids bubbles
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when a taken branch needs to flush out the pipeline.
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Moving target load instructions out of loops means they are executed
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less frequently. */
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/* An obstack to hold the def-use web data structures built up for
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migrating branch target load instructions. */
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static struct obstack migrate_btrl_obstack;
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/* Array indexed by basic block number, giving the set of registers
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live in that block. */
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static HARD_REG_SET *btrs_live;
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/* Array indexed by basic block number, giving the set of registers live at
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the end of that block, including any uses by a final jump insn, if any. */
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static HARD_REG_SET *btrs_live_at_end;
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/* Set of all target registers that we are willing to allocate. */
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static HARD_REG_SET all_btrs;
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/* Provide lower and upper bounds for target register numbers, so that
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we don't need to search through all the hard registers all the time. */
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static int first_btr, last_btr;
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/* Return an estimate of the frequency of execution of block bb. */
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static int
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basic_block_freq (basic_block bb)
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{
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return bb->frequency;
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}
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static rtx *btr_reference_found;
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/* A subroutine of btr_referenced_p, called through for_each_rtx.
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PREG is a pointer to an rtx that is to be excluded from the
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traversal. If we find a reference to a target register anywhere
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else, return 1, and put a pointer to it into btr_reference_found. */
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static int
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find_btr_reference (rtx *px, void *preg)
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{
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rtx x;
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int regno, i;
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if (px == preg)
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return -1;
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x = *px;
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if (!REG_P (x))
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return 0;
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regno = REGNO (x);
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for (i = hard_regno_nregs[regno][GET_MODE (x)] - 1; i >= 0; i--)
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if (TEST_HARD_REG_BIT (all_btrs, regno+i))
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{
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btr_reference_found = px;
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return 1;
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}
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return -1;
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}
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/* Return nonzero if X references (sets or reads) any branch target register.
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If EXCLUDEP is set, disregard any references within the rtx pointed to
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by it. If returning nonzero, also set btr_reference_found as above. */
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static int
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btr_referenced_p (rtx x, rtx *excludep)
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{
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return for_each_rtx (&x, find_btr_reference, excludep);
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}
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/* Return true if insn is an instruction that sets a target register.
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if CHECK_CONST is true, only return true if the source is constant.
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If such a set is found and REGNO is nonzero, assign the register number
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of the destination register to *REGNO. */
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static int
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insn_sets_btr_p (rtx insn, int check_const, int *regno)
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{
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rtx set;
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if (NONJUMP_INSN_P (insn)
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&& (set = single_set (insn)))
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{
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rtx dest = SET_DEST (set);
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rtx src = SET_SRC (set);
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if (GET_CODE (dest) == SUBREG)
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dest = XEXP (dest, 0);
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if (REG_P (dest)
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&& TEST_HARD_REG_BIT (all_btrs, REGNO (dest)))
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{
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gcc_assert (!btr_referenced_p (src, NULL));
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if (!check_const || CONSTANT_P (src))
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{
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if (regno)
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*regno = REGNO (dest);
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return 1;
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}
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}
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}
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return 0;
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}
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/* Find and return a use of a target register within an instruction INSN. */
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static rtx *
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find_btr_use (rtx insn)
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{
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return btr_referenced_p (insn, NULL) ? btr_reference_found : NULL;
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}
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/* Find the group that the target register definition DEF belongs
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to in the list starting with *ALL_BTR_DEF_GROUPS. If no such
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group exists, create one. Add def to the group. */
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static void
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find_btr_def_group (btr_def_group *all_btr_def_groups, btr_def def)
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{
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if (insn_sets_btr_p (def->insn, 1, NULL))
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{
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btr_def_group this_group;
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rtx def_src = SET_SRC (single_set (def->insn));
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/* ?? This linear search is an efficiency concern, particularly
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as the search will almost always fail to find a match. */
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for (this_group = *all_btr_def_groups;
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this_group != NULL;
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this_group = this_group->next)
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if (rtx_equal_p (def_src, this_group->src))
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break;
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if (!this_group)
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{
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this_group = obstack_alloc (&migrate_btrl_obstack,
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sizeof (struct btr_def_group_s));
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this_group->src = def_src;
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this_group->members = NULL;
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this_group->next = *all_btr_def_groups;
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*all_btr_def_groups = this_group;
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}
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def->group = this_group;
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def->next_this_group = this_group->members;
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this_group->members = def;
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}
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else
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def->group = NULL;
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}
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/* Create a new target register definition structure, for a definition in
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block BB, instruction INSN, and insert it into ALL_BTR_DEFS. Return
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the new definition. */
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static btr_def
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add_btr_def (fibheap_t all_btr_defs, basic_block bb, int insn_luid, rtx insn,
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unsigned int dest_reg, int other_btr_uses_before_def,
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btr_def_group *all_btr_def_groups)
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{
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btr_def this
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= obstack_alloc (&migrate_btrl_obstack, sizeof (struct btr_def_s));
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this->bb = bb;
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this->luid = insn_luid;
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this->insn = insn;
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this->btr = dest_reg;
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this->cost = basic_block_freq (bb);
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this->has_ambiguous_use = 0;
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this->other_btr_uses_before_def = other_btr_uses_before_def;
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this->other_btr_uses_after_use = 0;
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this->next_this_bb = NULL;
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this->next_this_group = NULL;
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this->uses = NULL;
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this->live_range = NULL;
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find_btr_def_group (all_btr_def_groups, this);
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fibheap_insert (all_btr_defs, -this->cost, this);
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if (dump_file)
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fprintf (dump_file,
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"Found target reg definition: sets %u { bb %d, insn %d }%s priority %d\n",
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dest_reg, bb->index, INSN_UID (insn), (this->group ? "" : ":not const"),
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this->cost);
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return this;
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}
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/* Create a new target register user structure, for a use in block BB,
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instruction INSN. Return the new user. */
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static btr_user
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new_btr_user (basic_block bb, int insn_luid, rtx insn)
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{
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/* This instruction reads target registers. We need
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to decide whether we can replace all target register
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uses easily.
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*/
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rtx *usep = find_btr_use (PATTERN (insn));
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rtx use;
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btr_user user = NULL;
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if (usep)
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{
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int unambiguous_single_use;
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/* We want to ensure that USE is the only use of a target
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register in INSN, so that we know that to rewrite INSN to use
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a different target register, all we have to do is replace USE. */
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unambiguous_single_use = !btr_referenced_p (PATTERN (insn), usep);
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if (!unambiguous_single_use)
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usep = NULL;
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}
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use = usep ? *usep : NULL_RTX;
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user = obstack_alloc (&migrate_btrl_obstack, sizeof (struct btr_user_s));
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user->bb = bb;
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user->luid = insn_luid;
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user->insn = insn;
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user->use = use;
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user->other_use_this_block = 0;
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user->next = NULL;
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user->n_reaching_defs = 0;
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user->first_reaching_def = -1;
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if (dump_file)
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{
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fprintf (dump_file, "Uses target reg: { bb %d, insn %d }",
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bb->index, INSN_UID (insn));
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if (user->use)
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fprintf (dump_file, ": unambiguous use of reg %d\n",
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REGNO (user->use));
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}
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return user;
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}
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/* Write the contents of S to the dump file. */
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static void
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dump_hard_reg_set (HARD_REG_SET s)
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{
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int reg;
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for (reg = 0; reg < FIRST_PSEUDO_REGISTER; reg++)
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if (TEST_HARD_REG_BIT (s, reg))
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fprintf (dump_file, " %d", reg);
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}
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/* Write the set of target regs live in block BB to the dump file. */
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static void
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dump_btrs_live (int bb)
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{
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fprintf (dump_file, "BB%d live:", bb);
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dump_hard_reg_set (btrs_live[bb]);
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fprintf (dump_file, "\n");
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}
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/* REGNO is the number of a branch target register that is being used or
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set. USERS_THIS_BB is a list of preceding branch target register users;
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If any of them use the same register, set their other_use_this_block
|
||
flag. */
|
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static void
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note_other_use_this_block (unsigned int regno, btr_user users_this_bb)
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||
{
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||
btr_user user;
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||
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for (user = users_this_bb; user != NULL; user = user->next)
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if (user->use && REGNO (user->use) == regno)
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user->other_use_this_block = 1;
|
||
}
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||
|
||
typedef struct {
|
||
btr_user users_this_bb;
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||
HARD_REG_SET btrs_written_in_block;
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||
HARD_REG_SET btrs_live_in_block;
|
||
sbitmap bb_gen;
|
||
sbitmap *btr_defset;
|
||
} defs_uses_info;
|
||
|
||
/* Called via note_stores or directly to register stores into /
|
||
clobbers of a branch target register DEST that are not recognized as
|
||
straightforward definitions. DATA points to information about the
|
||
current basic block that needs updating. */
|
||
static void
|
||
note_btr_set (rtx dest, rtx set ATTRIBUTE_UNUSED, void *data)
|
||
{
|
||
defs_uses_info *info = data;
|
||
int regno, end_regno;
|
||
|
||
if (!REG_P (dest))
|
||
return;
|
||
regno = REGNO (dest);
|
||
end_regno = regno + hard_regno_nregs[regno][GET_MODE (dest)];
|
||
for (; regno < end_regno; regno++)
|
||
if (TEST_HARD_REG_BIT (all_btrs, regno))
|
||
{
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||
note_other_use_this_block (regno, info->users_this_bb);
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||
SET_HARD_REG_BIT (info->btrs_written_in_block, regno);
|
||
SET_HARD_REG_BIT (info->btrs_live_in_block, regno);
|
||
sbitmap_difference (info->bb_gen, info->bb_gen,
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||
info->btr_defset[regno - first_btr]);
|
||
}
|
||
}
|
||
|
||
static void
|
||
compute_defs_uses_and_gen (fibheap_t all_btr_defs, btr_def *def_array,
|
||
btr_user *use_array, sbitmap *btr_defset,
|
||
sbitmap *bb_gen, HARD_REG_SET *btrs_written)
|
||
{
|
||
/* Scan the code building up the set of all defs and all uses.
|
||
For each target register, build the set of defs of that register.
|
||
For each block, calculate the set of target registers
|
||
written in that block.
|
||
Also calculate the set of btrs ever live in that block.
|
||
*/
|
||
int i;
|
||
int insn_luid = 0;
|
||
btr_def_group all_btr_def_groups = NULL;
|
||
defs_uses_info info;
|
||
|
||
sbitmap_vector_zero (bb_gen, n_basic_blocks);
|
||
for (i = NUM_FIXED_BLOCKS; i < n_basic_blocks; i++)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
int reg;
|
||
btr_def defs_this_bb = NULL;
|
||
rtx insn;
|
||
rtx last;
|
||
int can_throw = 0;
|
||
|
||
info.users_this_bb = NULL;
|
||
info.bb_gen = bb_gen[i];
|
||
info.btr_defset = btr_defset;
|
||
|
||
CLEAR_HARD_REG_SET (info.btrs_live_in_block);
|
||
CLEAR_HARD_REG_SET (info.btrs_written_in_block);
|
||
for (reg = first_btr; reg <= last_btr; reg++)
|
||
if (TEST_HARD_REG_BIT (all_btrs, reg)
|
||
&& REGNO_REG_SET_P (bb->il.rtl->global_live_at_start, reg))
|
||
SET_HARD_REG_BIT (info.btrs_live_in_block, reg);
|
||
|
||
for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb));
|
||
insn != last;
|
||
insn = NEXT_INSN (insn), insn_luid++)
|
||
{
|
||
if (INSN_P (insn))
|
||
{
|
||
int regno;
|
||
int insn_uid = INSN_UID (insn);
|
||
|
||
if (insn_sets_btr_p (insn, 0, ®no))
|
||
{
|
||
btr_def def = add_btr_def (
|
||
all_btr_defs, bb, insn_luid, insn, regno,
|
||
TEST_HARD_REG_BIT (info.btrs_live_in_block, regno),
|
||
&all_btr_def_groups);
|
||
|
||
def_array[insn_uid] = def;
|
||
SET_HARD_REG_BIT (info.btrs_written_in_block, regno);
|
||
SET_HARD_REG_BIT (info.btrs_live_in_block, regno);
|
||
sbitmap_difference (bb_gen[i], bb_gen[i],
|
||
btr_defset[regno - first_btr]);
|
||
SET_BIT (bb_gen[i], insn_uid);
|
||
def->next_this_bb = defs_this_bb;
|
||
defs_this_bb = def;
|
||
SET_BIT (btr_defset[regno - first_btr], insn_uid);
|
||
note_other_use_this_block (regno, info.users_this_bb);
|
||
}
|
||
/* Check for the blockage emitted by expand_nl_goto_receiver. */
|
||
else if (current_function_has_nonlocal_label
|
||
&& GET_CODE (PATTERN (insn)) == ASM_INPUT)
|
||
{
|
||
btr_user user;
|
||
|
||
/* Do the equivalent of calling note_other_use_this_block
|
||
for every target register. */
|
||
for (user = info.users_this_bb; user != NULL;
|
||
user = user->next)
|
||
if (user->use)
|
||
user->other_use_this_block = 1;
|
||
IOR_HARD_REG_SET (info.btrs_written_in_block, all_btrs);
|
||
IOR_HARD_REG_SET (info.btrs_live_in_block, all_btrs);
|
||
sbitmap_zero (info.bb_gen);
|
||
}
|
||
else
|
||
{
|
||
if (btr_referenced_p (PATTERN (insn), NULL))
|
||
{
|
||
btr_user user = new_btr_user (bb, insn_luid, insn);
|
||
|
||
use_array[insn_uid] = user;
|
||
if (user->use)
|
||
SET_HARD_REG_BIT (info.btrs_live_in_block,
|
||
REGNO (user->use));
|
||
else
|
||
{
|
||
int reg;
|
||
for (reg = first_btr; reg <= last_btr; reg++)
|
||
if (TEST_HARD_REG_BIT (all_btrs, reg)
|
||
&& refers_to_regno_p (reg, reg + 1, user->insn,
|
||
NULL))
|
||
{
|
||
note_other_use_this_block (reg,
|
||
info.users_this_bb);
|
||
SET_HARD_REG_BIT (info.btrs_live_in_block, reg);
|
||
}
|
||
note_stores (PATTERN (insn), note_btr_set, &info);
|
||
}
|
||
user->next = info.users_this_bb;
|
||
info.users_this_bb = user;
|
||
}
|
||
if (CALL_P (insn))
|
||
{
|
||
HARD_REG_SET *clobbered = &call_used_reg_set;
|
||
HARD_REG_SET call_saved;
|
||
rtx pat = PATTERN (insn);
|
||
int i;
|
||
|
||
/* Check for sibcall. */
|
||
if (GET_CODE (pat) == PARALLEL)
|
||
for (i = XVECLEN (pat, 0) - 1; i >= 0; i--)
|
||
if (GET_CODE (XVECEXP (pat, 0, i)) == RETURN)
|
||
{
|
||
COMPL_HARD_REG_SET (call_saved,
|
||
call_used_reg_set);
|
||
clobbered = &call_saved;
|
||
}
|
||
|
||
for (regno = first_btr; regno <= last_btr; regno++)
|
||
if (TEST_HARD_REG_BIT (*clobbered, regno))
|
||
note_btr_set (regno_reg_rtx[regno], NULL_RTX, &info);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
COPY_HARD_REG_SET (btrs_live[i], info.btrs_live_in_block);
|
||
COPY_HARD_REG_SET (btrs_written[i], info.btrs_written_in_block);
|
||
|
||
REG_SET_TO_HARD_REG_SET (btrs_live_at_end[i], bb->il.rtl->global_live_at_end);
|
||
/* If this block ends in a jump insn, add any uses or even clobbers
|
||
of branch target registers that it might have. */
|
||
for (insn = BB_END (bb); insn != BB_HEAD (bb) && ! INSN_P (insn); )
|
||
insn = PREV_INSN (insn);
|
||
/* ??? for the fall-through edge, it would make sense to insert the
|
||
btr set on the edge, but that would require to split the block
|
||
early on so that we can distinguish between dominance from the fall
|
||
through edge - which can use the call-clobbered registers - from
|
||
dominance by the throw edge. */
|
||
if (can_throw_internal (insn))
|
||
{
|
||
HARD_REG_SET tmp;
|
||
|
||
COPY_HARD_REG_SET (tmp, call_used_reg_set);
|
||
AND_HARD_REG_SET (tmp, all_btrs);
|
||
IOR_HARD_REG_SET (btrs_live_at_end[i], tmp);
|
||
can_throw = 1;
|
||
}
|
||
if (can_throw || JUMP_P (insn))
|
||
{
|
||
int regno;
|
||
|
||
for (regno = first_btr; regno <= last_btr; regno++)
|
||
if (refers_to_regno_p (regno, regno+1, insn, NULL))
|
||
SET_HARD_REG_BIT (btrs_live_at_end[i], regno);
|
||
}
|
||
|
||
if (dump_file)
|
||
dump_btrs_live(i);
|
||
}
|
||
}
|
||
|
||
static void
|
||
compute_kill (sbitmap *bb_kill, sbitmap *btr_defset,
|
||
HARD_REG_SET *btrs_written)
|
||
{
|
||
int i;
|
||
int regno;
|
||
|
||
/* For each basic block, form the set BB_KILL - the set
|
||
of definitions that the block kills. */
|
||
sbitmap_vector_zero (bb_kill, n_basic_blocks);
|
||
for (i = NUM_FIXED_BLOCKS; i < n_basic_blocks; i++)
|
||
{
|
||
for (regno = first_btr; regno <= last_btr; regno++)
|
||
if (TEST_HARD_REG_BIT (all_btrs, regno)
|
||
&& TEST_HARD_REG_BIT (btrs_written[i], regno))
|
||
sbitmap_a_or_b (bb_kill[i], bb_kill[i],
|
||
btr_defset[regno - first_btr]);
|
||
}
|
||
}
|
||
|
||
static void
|
||
compute_out (sbitmap *bb_out, sbitmap *bb_gen, sbitmap *bb_kill, int max_uid)
|
||
{
|
||
/* Perform iterative dataflow:
|
||
Initially, for all blocks, BB_OUT = BB_GEN.
|
||
For each block,
|
||
BB_IN = union over predecessors of BB_OUT(pred)
|
||
BB_OUT = (BB_IN - BB_KILL) + BB_GEN
|
||
Iterate until the bb_out sets stop growing. */
|
||
int i;
|
||
int changed;
|
||
sbitmap bb_in = sbitmap_alloc (max_uid);
|
||
|
||
for (i = NUM_FIXED_BLOCKS; i < n_basic_blocks; i++)
|
||
sbitmap_copy (bb_out[i], bb_gen[i]);
|
||
|
||
changed = 1;
|
||
while (changed)
|
||
{
|
||
changed = 0;
|
||
for (i = NUM_FIXED_BLOCKS; i < n_basic_blocks; i++)
|
||
{
|
||
sbitmap_union_of_preds (bb_in, bb_out, i);
|
||
changed |= sbitmap_union_of_diff_cg (bb_out[i], bb_gen[i],
|
||
bb_in, bb_kill[i]);
|
||
}
|
||
}
|
||
sbitmap_free (bb_in);
|
||
}
|
||
|
||
static void
|
||
link_btr_uses (btr_def *def_array, btr_user *use_array, sbitmap *bb_out,
|
||
sbitmap *btr_defset, int max_uid)
|
||
{
|
||
int i;
|
||
sbitmap reaching_defs = sbitmap_alloc (max_uid);
|
||
|
||
/* Link uses to the uses lists of all of their reaching defs.
|
||
Count up the number of reaching defs of each use. */
|
||
for (i = NUM_FIXED_BLOCKS; i < n_basic_blocks; i++)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
rtx insn;
|
||
rtx last;
|
||
|
||
sbitmap_union_of_preds (reaching_defs, bb_out, i);
|
||
for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb));
|
||
insn != last;
|
||
insn = NEXT_INSN (insn))
|
||
{
|
||
if (INSN_P (insn))
|
||
{
|
||
int insn_uid = INSN_UID (insn);
|
||
|
||
btr_def def = def_array[insn_uid];
|
||
btr_user user = use_array[insn_uid];
|
||
if (def != NULL)
|
||
{
|
||
/* Remove all reaching defs of regno except
|
||
for this one. */
|
||
sbitmap_difference (reaching_defs, reaching_defs,
|
||
btr_defset[def->btr - first_btr]);
|
||
SET_BIT(reaching_defs, insn_uid);
|
||
}
|
||
|
||
if (user != NULL)
|
||
{
|
||
/* Find all the reaching defs for this use. */
|
||
sbitmap reaching_defs_of_reg = sbitmap_alloc(max_uid);
|
||
unsigned int uid = 0;
|
||
sbitmap_iterator sbi;
|
||
|
||
if (user->use)
|
||
sbitmap_a_and_b (
|
||
reaching_defs_of_reg,
|
||
reaching_defs,
|
||
btr_defset[REGNO (user->use) - first_btr]);
|
||
else
|
||
{
|
||
int reg;
|
||
|
||
sbitmap_zero (reaching_defs_of_reg);
|
||
for (reg = first_btr; reg <= last_btr; reg++)
|
||
if (TEST_HARD_REG_BIT (all_btrs, reg)
|
||
&& refers_to_regno_p (reg, reg + 1, user->insn,
|
||
NULL))
|
||
sbitmap_a_or_b_and_c (reaching_defs_of_reg,
|
||
reaching_defs_of_reg,
|
||
reaching_defs,
|
||
btr_defset[reg - first_btr]);
|
||
}
|
||
EXECUTE_IF_SET_IN_SBITMAP (reaching_defs_of_reg, 0, uid, sbi)
|
||
{
|
||
btr_def def = def_array[uid];
|
||
|
||
/* We now know that def reaches user. */
|
||
|
||
if (dump_file)
|
||
fprintf (dump_file,
|
||
"Def in insn %d reaches use in insn %d\n",
|
||
uid, insn_uid);
|
||
|
||
user->n_reaching_defs++;
|
||
if (!user->use)
|
||
def->has_ambiguous_use = 1;
|
||
if (user->first_reaching_def != -1)
|
||
{ /* There is more than one reaching def. This is
|
||
a rare case, so just give up on this def/use
|
||
web when it occurs. */
|
||
def->has_ambiguous_use = 1;
|
||
def_array[user->first_reaching_def]
|
||
->has_ambiguous_use = 1;
|
||
if (dump_file)
|
||
fprintf (dump_file,
|
||
"(use %d has multiple reaching defs)\n",
|
||
insn_uid);
|
||
}
|
||
else
|
||
user->first_reaching_def = uid;
|
||
if (user->other_use_this_block)
|
||
def->other_btr_uses_after_use = 1;
|
||
user->next = def->uses;
|
||
def->uses = user;
|
||
}
|
||
sbitmap_free (reaching_defs_of_reg);
|
||
}
|
||
|
||
if (CALL_P (insn))
|
||
{
|
||
int regno;
|
||
|
||
for (regno = first_btr; regno <= last_btr; regno++)
|
||
if (TEST_HARD_REG_BIT (all_btrs, regno)
|
||
&& TEST_HARD_REG_BIT (call_used_reg_set, regno))
|
||
sbitmap_difference (reaching_defs, reaching_defs,
|
||
btr_defset[regno - first_btr]);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
sbitmap_free (reaching_defs);
|
||
}
|
||
|
||
static void
|
||
build_btr_def_use_webs (fibheap_t all_btr_defs)
|
||
{
|
||
const int max_uid = get_max_uid ();
|
||
btr_def *def_array = XCNEWVEC (btr_def, max_uid);
|
||
btr_user *use_array = XCNEWVEC (btr_user, max_uid);
|
||
sbitmap *btr_defset = sbitmap_vector_alloc (
|
||
(last_btr - first_btr) + 1, max_uid);
|
||
sbitmap *bb_gen = sbitmap_vector_alloc (n_basic_blocks, max_uid);
|
||
HARD_REG_SET *btrs_written = XCNEWVEC (HARD_REG_SET, n_basic_blocks);
|
||
sbitmap *bb_kill;
|
||
sbitmap *bb_out;
|
||
|
||
sbitmap_vector_zero (btr_defset, (last_btr - first_btr) + 1);
|
||
|
||
compute_defs_uses_and_gen (all_btr_defs, def_array, use_array, btr_defset,
|
||
bb_gen, btrs_written);
|
||
|
||
bb_kill = sbitmap_vector_alloc (n_basic_blocks, max_uid);
|
||
compute_kill (bb_kill, btr_defset, btrs_written);
|
||
free (btrs_written);
|
||
|
||
bb_out = sbitmap_vector_alloc (n_basic_blocks, max_uid);
|
||
compute_out (bb_out, bb_gen, bb_kill, max_uid);
|
||
|
||
sbitmap_vector_free (bb_gen);
|
||
sbitmap_vector_free (bb_kill);
|
||
|
||
link_btr_uses (def_array, use_array, bb_out, btr_defset, max_uid);
|
||
|
||
sbitmap_vector_free (bb_out);
|
||
sbitmap_vector_free (btr_defset);
|
||
free (use_array);
|
||
free (def_array);
|
||
}
|
||
|
||
/* Return true if basic block BB contains the start or end of the
|
||
live range of the definition DEF, AND there are other live
|
||
ranges of the same target register that include BB. */
|
||
static int
|
||
block_at_edge_of_live_range_p (int bb, btr_def def)
|
||
{
|
||
if (def->other_btr_uses_before_def && BASIC_BLOCK (bb) == def->bb)
|
||
return 1;
|
||
else if (def->other_btr_uses_after_use)
|
||
{
|
||
btr_user user;
|
||
for (user = def->uses; user != NULL; user = user->next)
|
||
if (BASIC_BLOCK (bb) == user->bb)
|
||
return 1;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/* We are removing the def/use web DEF. The target register
|
||
used in this web is therefore no longer live in the live range
|
||
of this web, so remove it from the live set of all basic blocks
|
||
in the live range of the web.
|
||
Blocks at the boundary of the live range may contain other live
|
||
ranges for the same target register, so we have to be careful
|
||
to remove the target register from the live set of these blocks
|
||
only if they do not contain other live ranges for the same register. */
|
||
static void
|
||
clear_btr_from_live_range (btr_def def)
|
||
{
|
||
unsigned bb;
|
||
bitmap_iterator bi;
|
||
|
||
EXECUTE_IF_SET_IN_BITMAP (def->live_range, 0, bb, bi)
|
||
{
|
||
if ((!def->other_btr_uses_before_def
|
||
&& !def->other_btr_uses_after_use)
|
||
|| !block_at_edge_of_live_range_p (bb, def))
|
||
{
|
||
CLEAR_HARD_REG_BIT (btrs_live[bb], def->btr);
|
||
CLEAR_HARD_REG_BIT (btrs_live_at_end[bb], def->btr);
|
||
if (dump_file)
|
||
dump_btrs_live (bb);
|
||
}
|
||
}
|
||
if (def->own_end)
|
||
CLEAR_HARD_REG_BIT (btrs_live_at_end[def->bb->index], def->btr);
|
||
}
|
||
|
||
|
||
/* We are adding the def/use web DEF. Add the target register used
|
||
in this web to the live set of all of the basic blocks that contain
|
||
the live range of the web.
|
||
If OWN_END is set, also show that the register is live from our
|
||
definitions at the end of the basic block where it is defined. */
|
||
static void
|
||
add_btr_to_live_range (btr_def def, int own_end)
|
||
{
|
||
unsigned bb;
|
||
bitmap_iterator bi;
|
||
|
||
EXECUTE_IF_SET_IN_BITMAP (def->live_range, 0, bb, bi)
|
||
{
|
||
SET_HARD_REG_BIT (btrs_live[bb], def->btr);
|
||
SET_HARD_REG_BIT (btrs_live_at_end[bb], def->btr);
|
||
if (dump_file)
|
||
dump_btrs_live (bb);
|
||
}
|
||
if (own_end)
|
||
{
|
||
SET_HARD_REG_BIT (btrs_live_at_end[def->bb->index], def->btr);
|
||
def->own_end = 1;
|
||
}
|
||
}
|
||
|
||
/* Update a live range to contain the basic block NEW_BLOCK, and all
|
||
blocks on paths between the existing live range and NEW_BLOCK.
|
||
HEAD is a block contained in the existing live range that dominates
|
||
all other blocks in the existing live range.
|
||
Also add to the set BTRS_LIVE_IN_RANGE all target registers that
|
||
are live in the blocks that we add to the live range.
|
||
If FULL_RANGE is set, include the full live range of NEW_BB;
|
||
otherwise, if NEW_BB dominates HEAD_BB, only add registers that
|
||
are life at the end of NEW_BB for NEW_BB itself.
|
||
It is a precondition that either NEW_BLOCK dominates HEAD,or
|
||
HEAD dom NEW_BLOCK. This is used to speed up the
|
||
implementation of this function. */
|
||
static void
|
||
augment_live_range (bitmap live_range, HARD_REG_SET *btrs_live_in_range,
|
||
basic_block head_bb, basic_block new_bb, int full_range)
|
||
{
|
||
basic_block *worklist, *tos;
|
||
|
||
tos = worklist = XNEWVEC (basic_block, n_basic_blocks + 1);
|
||
|
||
if (dominated_by_p (CDI_DOMINATORS, new_bb, head_bb))
|
||
{
|
||
if (new_bb == head_bb)
|
||
{
|
||
if (full_range)
|
||
IOR_HARD_REG_SET (*btrs_live_in_range, btrs_live[new_bb->index]);
|
||
free (tos);
|
||
return;
|
||
}
|
||
*tos++ = new_bb;
|
||
}
|
||
else
|
||
{
|
||
edge e;
|
||
edge_iterator ei;
|
||
int new_block = new_bb->index;
|
||
|
||
gcc_assert (dominated_by_p (CDI_DOMINATORS, head_bb, new_bb));
|
||
|
||
IOR_HARD_REG_SET (*btrs_live_in_range, btrs_live[head_bb->index]);
|
||
bitmap_set_bit (live_range, new_block);
|
||
/* A previous btr migration could have caused a register to be
|
||
live just at the end of new_block which we need in full, so
|
||
use trs_live_at_end even if full_range is set. */
|
||
IOR_HARD_REG_SET (*btrs_live_in_range, btrs_live_at_end[new_block]);
|
||
if (full_range)
|
||
IOR_HARD_REG_SET (*btrs_live_in_range, btrs_live[new_block]);
|
||
if (dump_file)
|
||
{
|
||
fprintf (dump_file,
|
||
"Adding end of block %d and rest of %d to live range\n",
|
||
new_block, head_bb->index);
|
||
fprintf (dump_file,"Now live btrs are ");
|
||
dump_hard_reg_set (*btrs_live_in_range);
|
||
fprintf (dump_file, "\n");
|
||
}
|
||
FOR_EACH_EDGE (e, ei, head_bb->preds)
|
||
*tos++ = e->src;
|
||
}
|
||
|
||
while (tos != worklist)
|
||
{
|
||
basic_block bb = *--tos;
|
||
if (!bitmap_bit_p (live_range, bb->index))
|
||
{
|
||
edge e;
|
||
edge_iterator ei;
|
||
|
||
bitmap_set_bit (live_range, bb->index);
|
||
IOR_HARD_REG_SET (*btrs_live_in_range,
|
||
btrs_live[bb->index]);
|
||
/* A previous btr migration could have caused a register to be
|
||
live just at the end of a block which we need in full. */
|
||
IOR_HARD_REG_SET (*btrs_live_in_range,
|
||
btrs_live_at_end[bb->index]);
|
||
if (dump_file)
|
||
{
|
||
fprintf (dump_file,
|
||
"Adding block %d to live range\n", bb->index);
|
||
fprintf (dump_file,"Now live btrs are ");
|
||
dump_hard_reg_set (*btrs_live_in_range);
|
||
fprintf (dump_file, "\n");
|
||
}
|
||
|
||
FOR_EACH_EDGE (e, ei, bb->preds)
|
||
{
|
||
basic_block pred = e->src;
|
||
if (!bitmap_bit_p (live_range, pred->index))
|
||
*tos++ = pred;
|
||
}
|
||
}
|
||
}
|
||
|
||
free (worklist);
|
||
}
|
||
|
||
/* Return the most desirable target register that is not in
|
||
the set USED_BTRS. */
|
||
static int
|
||
choose_btr (HARD_REG_SET used_btrs)
|
||
{
|
||
int i;
|
||
GO_IF_HARD_REG_SUBSET (all_btrs, used_btrs, give_up);
|
||
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
{
|
||
#ifdef REG_ALLOC_ORDER
|
||
int regno = reg_alloc_order[i];
|
||
#else
|
||
int regno = i;
|
||
#endif
|
||
if (TEST_HARD_REG_BIT (all_btrs, regno)
|
||
&& !TEST_HARD_REG_BIT (used_btrs, regno))
|
||
return regno;
|
||
}
|
||
give_up:
|
||
return -1;
|
||
}
|
||
|
||
/* Calculate the set of basic blocks that contain the live range of
|
||
the def/use web DEF.
|
||
Also calculate the set of target registers that are live at time
|
||
in this live range, but ignore the live range represented by DEF
|
||
when calculating this set. */
|
||
static void
|
||
btr_def_live_range (btr_def def, HARD_REG_SET *btrs_live_in_range)
|
||
{
|
||
if (!def->live_range)
|
||
{
|
||
btr_user user;
|
||
|
||
def->live_range = BITMAP_ALLOC (NULL);
|
||
|
||
bitmap_set_bit (def->live_range, def->bb->index);
|
||
COPY_HARD_REG_SET (*btrs_live_in_range,
|
||
(flag_btr_bb_exclusive
|
||
? btrs_live : btrs_live_at_end)[def->bb->index]);
|
||
|
||
for (user = def->uses; user != NULL; user = user->next)
|
||
augment_live_range (def->live_range, btrs_live_in_range,
|
||
def->bb, user->bb,
|
||
(flag_btr_bb_exclusive
|
||
|| user->insn != BB_END (def->bb)
|
||
|| !JUMP_P (user->insn)));
|
||
}
|
||
else
|
||
{
|
||
/* def->live_range is accurate, but we need to recompute
|
||
the set of target registers live over it, because migration
|
||
of other PT instructions may have affected it.
|
||
*/
|
||
unsigned bb;
|
||
unsigned def_bb = flag_btr_bb_exclusive ? -1 : def->bb->index;
|
||
bitmap_iterator bi;
|
||
|
||
CLEAR_HARD_REG_SET (*btrs_live_in_range);
|
||
EXECUTE_IF_SET_IN_BITMAP (def->live_range, 0, bb, bi)
|
||
{
|
||
IOR_HARD_REG_SET (*btrs_live_in_range,
|
||
(def_bb == bb
|
||
? btrs_live_at_end : btrs_live) [bb]);
|
||
}
|
||
}
|
||
if (!def->other_btr_uses_before_def &&
|
||
!def->other_btr_uses_after_use)
|
||
CLEAR_HARD_REG_BIT (*btrs_live_in_range, def->btr);
|
||
}
|
||
|
||
/* Merge into the def/use web DEF any other def/use webs in the same
|
||
group that are dominated by DEF, provided that there is a target
|
||
register available to allocate to the merged web. */
|
||
static void
|
||
combine_btr_defs (btr_def def, HARD_REG_SET *btrs_live_in_range)
|
||
{
|
||
btr_def other_def;
|
||
|
||
for (other_def = def->group->members;
|
||
other_def != NULL;
|
||
other_def = other_def->next_this_group)
|
||
{
|
||
if (other_def != def
|
||
&& other_def->uses != NULL
|
||
&& ! other_def->has_ambiguous_use
|
||
&& dominated_by_p (CDI_DOMINATORS, other_def->bb, def->bb))
|
||
{
|
||
/* def->bb dominates the other def, so def and other_def could
|
||
be combined. */
|
||
/* Merge their live ranges, and get the set of
|
||
target registers live over the merged range. */
|
||
int btr;
|
||
HARD_REG_SET combined_btrs_live;
|
||
bitmap combined_live_range = BITMAP_ALLOC (NULL);
|
||
btr_user user;
|
||
|
||
if (other_def->live_range == NULL)
|
||
{
|
||
HARD_REG_SET dummy_btrs_live_in_range;
|
||
btr_def_live_range (other_def, &dummy_btrs_live_in_range);
|
||
}
|
||
COPY_HARD_REG_SET (combined_btrs_live, *btrs_live_in_range);
|
||
bitmap_copy (combined_live_range, def->live_range);
|
||
|
||
for (user = other_def->uses; user != NULL; user = user->next)
|
||
augment_live_range (combined_live_range, &combined_btrs_live,
|
||
def->bb, user->bb,
|
||
(flag_btr_bb_exclusive
|
||
|| user->insn != BB_END (def->bb)
|
||
|| !JUMP_P (user->insn)));
|
||
|
||
btr = choose_btr (combined_btrs_live);
|
||
if (btr != -1)
|
||
{
|
||
/* We can combine them. */
|
||
if (dump_file)
|
||
fprintf (dump_file,
|
||
"Combining def in insn %d with def in insn %d\n",
|
||
INSN_UID (other_def->insn), INSN_UID (def->insn));
|
||
|
||
def->btr = btr;
|
||
user = other_def->uses;
|
||
while (user != NULL)
|
||
{
|
||
btr_user next = user->next;
|
||
|
||
user->next = def->uses;
|
||
def->uses = user;
|
||
user = next;
|
||
}
|
||
/* Combining def/use webs can make target registers live
|
||
after uses where they previously were not. This means
|
||
some REG_DEAD notes may no longer be correct. We could
|
||
be more precise about this if we looked at the combined
|
||
live range, but here I just delete any REG_DEAD notes
|
||
in case they are no longer correct. */
|
||
for (user = def->uses; user != NULL; user = user->next)
|
||
remove_note (user->insn,
|
||
find_regno_note (user->insn, REG_DEAD,
|
||
REGNO (user->use)));
|
||
clear_btr_from_live_range (other_def);
|
||
other_def->uses = NULL;
|
||
bitmap_copy (def->live_range, combined_live_range);
|
||
if (other_def->btr == btr && other_def->other_btr_uses_after_use)
|
||
def->other_btr_uses_after_use = 1;
|
||
COPY_HARD_REG_SET (*btrs_live_in_range, combined_btrs_live);
|
||
|
||
/* Delete the old target register initialization. */
|
||
delete_insn (other_def->insn);
|
||
|
||
}
|
||
BITMAP_FREE (combined_live_range);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Move the definition DEF from its current position to basic
|
||
block NEW_DEF_BB, and modify it to use branch target register BTR.
|
||
Delete the old defining insn, and insert a new one in NEW_DEF_BB.
|
||
Update all reaching uses of DEF in the RTL to use BTR.
|
||
If this new position means that other defs in the
|
||
same group can be combined with DEF then combine them. */
|
||
static void
|
||
move_btr_def (basic_block new_def_bb, int btr, btr_def def, bitmap live_range,
|
||
HARD_REG_SET *btrs_live_in_range)
|
||
{
|
||
/* We can move the instruction.
|
||
Set a target register in block NEW_DEF_BB to the value
|
||
needed for this target register definition.
|
||
Replace all uses of the old target register definition by
|
||
uses of the new definition. Delete the old definition. */
|
||
basic_block b = new_def_bb;
|
||
rtx insp = BB_HEAD (b);
|
||
rtx old_insn = def->insn;
|
||
rtx src;
|
||
rtx btr_rtx;
|
||
rtx new_insn;
|
||
enum machine_mode btr_mode;
|
||
btr_user user;
|
||
rtx set;
|
||
|
||
if (dump_file)
|
||
fprintf(dump_file, "migrating to basic block %d, using reg %d\n",
|
||
new_def_bb->index, btr);
|
||
|
||
clear_btr_from_live_range (def);
|
||
def->btr = btr;
|
||
def->bb = new_def_bb;
|
||
def->luid = 0;
|
||
def->cost = basic_block_freq (new_def_bb);
|
||
bitmap_copy (def->live_range, live_range);
|
||
combine_btr_defs (def, btrs_live_in_range);
|
||
btr = def->btr;
|
||
def->other_btr_uses_before_def
|
||
= TEST_HARD_REG_BIT (btrs_live[b->index], btr) ? 1 : 0;
|
||
add_btr_to_live_range (def, 1);
|
||
if (LABEL_P (insp))
|
||
insp = NEXT_INSN (insp);
|
||
/* N.B.: insp is expected to be NOTE_INSN_BASIC_BLOCK now. Some
|
||
optimizations can result in insp being both first and last insn of
|
||
its basic block. */
|
||
/* ?? some assertions to check that insp is sensible? */
|
||
|
||
if (def->other_btr_uses_before_def)
|
||
{
|
||
insp = BB_END (b);
|
||
for (insp = BB_END (b); ! INSN_P (insp); insp = PREV_INSN (insp))
|
||
gcc_assert (insp != BB_HEAD (b));
|
||
|
||
if (JUMP_P (insp) || can_throw_internal (insp))
|
||
insp = PREV_INSN (insp);
|
||
}
|
||
|
||
set = single_set (old_insn);
|
||
src = SET_SRC (set);
|
||
btr_mode = GET_MODE (SET_DEST (set));
|
||
btr_rtx = gen_rtx_REG (btr_mode, btr);
|
||
|
||
new_insn = gen_move_insn (btr_rtx, src);
|
||
|
||
/* Insert target register initialization at head of basic block. */
|
||
def->insn = emit_insn_after (new_insn, insp);
|
||
|
||
regs_ever_live[btr] = 1;
|
||
|
||
if (dump_file)
|
||
fprintf (dump_file, "New pt is insn %d, inserted after insn %d\n",
|
||
INSN_UID (def->insn), INSN_UID (insp));
|
||
|
||
/* Delete the old target register initialization. */
|
||
delete_insn (old_insn);
|
||
|
||
/* Replace each use of the old target register by a use of the new target
|
||
register. */
|
||
for (user = def->uses; user != NULL; user = user->next)
|
||
{
|
||
/* Some extra work here to ensure consistent modes, because
|
||
it seems that a target register REG rtx can be given a different
|
||
mode depending on the context (surely that should not be
|
||
the case?). */
|
||
rtx replacement_rtx;
|
||
if (GET_MODE (user->use) == GET_MODE (btr_rtx)
|
||
|| GET_MODE (user->use) == VOIDmode)
|
||
replacement_rtx = btr_rtx;
|
||
else
|
||
replacement_rtx = gen_rtx_REG (GET_MODE (user->use), btr);
|
||
replace_rtx (user->insn, user->use, replacement_rtx);
|
||
user->use = replacement_rtx;
|
||
}
|
||
}
|
||
|
||
/* We anticipate intra-block scheduling to be done. See if INSN could move
|
||
up within BB by N_INSNS. */
|
||
static int
|
||
can_move_up (basic_block bb, rtx insn, int n_insns)
|
||
{
|
||
while (insn != BB_HEAD (bb) && n_insns > 0)
|
||
{
|
||
insn = PREV_INSN (insn);
|
||
/* ??? What if we have an anti-dependency that actually prevents the
|
||
scheduler from doing the move? We'd like to re-allocate the register,
|
||
but not necessarily put the load into another basic block. */
|
||
if (INSN_P (insn))
|
||
n_insns--;
|
||
}
|
||
return n_insns <= 0;
|
||
}
|
||
|
||
/* Attempt to migrate the target register definition DEF to an
|
||
earlier point in the flowgraph.
|
||
|
||
It is a precondition of this function that DEF is migratable:
|
||
i.e. it has a constant source, and all uses are unambiguous.
|
||
|
||
Only migrations that reduce the cost of DEF will be made.
|
||
MIN_COST is the lower bound on the cost of the DEF after migration.
|
||
If we migrate DEF so that its cost falls below MIN_COST,
|
||
then we do not attempt to migrate further. The idea is that
|
||
we migrate definitions in a priority order based on their cost,
|
||
when the cost of this definition falls below MIN_COST, then
|
||
there is another definition with cost == MIN_COST which now
|
||
has a higher priority than this definition.
|
||
|
||
Return nonzero if there may be benefit from attempting to
|
||
migrate this DEF further (i.e. we have reduced the cost below
|
||
MIN_COST, but we may be able to reduce it further).
|
||
Return zero if no further migration is possible. */
|
||
static int
|
||
migrate_btr_def (btr_def def, int min_cost)
|
||
{
|
||
bitmap live_range;
|
||
HARD_REG_SET btrs_live_in_range;
|
||
int btr_used_near_def = 0;
|
||
int def_basic_block_freq;
|
||
basic_block try;
|
||
int give_up = 0;
|
||
int def_moved = 0;
|
||
btr_user user;
|
||
int def_latency;
|
||
|
||
if (dump_file)
|
||
fprintf (dump_file,
|
||
"Attempting to migrate pt from insn %d (cost = %d, min_cost = %d) ... ",
|
||
INSN_UID (def->insn), def->cost, min_cost);
|
||
|
||
if (!def->group || def->has_ambiguous_use)
|
||
/* These defs are not migratable. */
|
||
{
|
||
if (dump_file)
|
||
fprintf (dump_file, "it's not migratable\n");
|
||
return 0;
|
||
}
|
||
|
||
if (!def->uses)
|
||
/* We have combined this def with another in the same group, so
|
||
no need to consider it further.
|
||
*/
|
||
{
|
||
if (dump_file)
|
||
fprintf (dump_file, "it's already combined with another pt\n");
|
||
return 0;
|
||
}
|
||
|
||
btr_def_live_range (def, &btrs_live_in_range);
|
||
live_range = BITMAP_ALLOC (NULL);
|
||
bitmap_copy (live_range, def->live_range);
|
||
|
||
#ifdef INSN_SCHEDULING
|
||
def_latency = insn_default_latency (def->insn) * issue_rate;
|
||
#else
|
||
def_latency = issue_rate;
|
||
#endif
|
||
|
||
for (user = def->uses; user != NULL; user = user->next)
|
||
{
|
||
if (user->bb == def->bb
|
||
&& user->luid > def->luid
|
||
&& (def->luid + def_latency) > user->luid
|
||
&& ! can_move_up (def->bb, def->insn,
|
||
(def->luid + def_latency) - user->luid))
|
||
{
|
||
btr_used_near_def = 1;
|
||
break;
|
||
}
|
||
}
|
||
|
||
def_basic_block_freq = basic_block_freq (def->bb);
|
||
|
||
for (try = get_immediate_dominator (CDI_DOMINATORS, def->bb);
|
||
!give_up && try && try != ENTRY_BLOCK_PTR && def->cost >= min_cost;
|
||
try = get_immediate_dominator (CDI_DOMINATORS, try))
|
||
{
|
||
/* Try to move the instruction that sets the target register into
|
||
basic block TRY. */
|
||
int try_freq = basic_block_freq (try);
|
||
edge_iterator ei;
|
||
edge e;
|
||
|
||
/* If TRY has abnormal edges, skip it. */
|
||
FOR_EACH_EDGE (e, ei, try->succs)
|
||
if (e->flags & EDGE_COMPLEX)
|
||
break;
|
||
if (e)
|
||
continue;
|
||
|
||
if (dump_file)
|
||
fprintf (dump_file, "trying block %d ...", try->index);
|
||
|
||
if (try_freq < def_basic_block_freq
|
||
|| (try_freq == def_basic_block_freq && btr_used_near_def))
|
||
{
|
||
int btr;
|
||
augment_live_range (live_range, &btrs_live_in_range, def->bb, try,
|
||
flag_btr_bb_exclusive);
|
||
if (dump_file)
|
||
{
|
||
fprintf (dump_file, "Now btrs live in range are: ");
|
||
dump_hard_reg_set (btrs_live_in_range);
|
||
fprintf (dump_file, "\n");
|
||
}
|
||
btr = choose_btr (btrs_live_in_range);
|
||
if (btr != -1)
|
||
{
|
||
move_btr_def (try, btr, def, live_range, &btrs_live_in_range);
|
||
bitmap_copy(live_range, def->live_range);
|
||
btr_used_near_def = 0;
|
||
def_moved = 1;
|
||
def_basic_block_freq = basic_block_freq (def->bb);
|
||
}
|
||
else
|
||
{
|
||
/* There are no free target registers available to move
|
||
this far forward, so give up */
|
||
give_up = 1;
|
||
if (dump_file)
|
||
fprintf (dump_file,
|
||
"giving up because there are no free target registers\n");
|
||
}
|
||
|
||
}
|
||
}
|
||
if (!def_moved)
|
||
{
|
||
give_up = 1;
|
||
if (dump_file)
|
||
fprintf (dump_file, "failed to move\n");
|
||
}
|
||
BITMAP_FREE (live_range);
|
||
return !give_up;
|
||
}
|
||
|
||
/* Attempt to move instructions that set target registers earlier
|
||
in the flowgraph, away from their corresponding uses. */
|
||
static void
|
||
migrate_btr_defs (enum reg_class btr_class, int allow_callee_save)
|
||
{
|
||
fibheap_t all_btr_defs = fibheap_new ();
|
||
int reg;
|
||
|
||
gcc_obstack_init (&migrate_btrl_obstack);
|
||
if (dump_file)
|
||
{
|
||
int i;
|
||
|
||
for (i = NUM_FIXED_BLOCKS; i < n_basic_blocks; i++)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
fprintf(dump_file,
|
||
"Basic block %d: count = " HOST_WIDEST_INT_PRINT_DEC
|
||
" loop-depth = %d idom = %d\n",
|
||
i, (HOST_WIDEST_INT) bb->count, bb->loop_depth,
|
||
get_immediate_dominator (CDI_DOMINATORS, bb)->index);
|
||
}
|
||
}
|
||
|
||
CLEAR_HARD_REG_SET (all_btrs);
|
||
for (first_btr = -1, reg = 0; reg < FIRST_PSEUDO_REGISTER; reg++)
|
||
if (TEST_HARD_REG_BIT (reg_class_contents[(int) btr_class], reg)
|
||
&& (allow_callee_save || call_used_regs[reg] || regs_ever_live[reg]))
|
||
{
|
||
SET_HARD_REG_BIT (all_btrs, reg);
|
||
last_btr = reg;
|
||
if (first_btr < 0)
|
||
first_btr = reg;
|
||
}
|
||
|
||
btrs_live = xcalloc (n_basic_blocks, sizeof (HARD_REG_SET));
|
||
btrs_live_at_end = xcalloc (n_basic_blocks, sizeof (HARD_REG_SET));
|
||
|
||
build_btr_def_use_webs (all_btr_defs);
|
||
|
||
while (!fibheap_empty (all_btr_defs))
|
||
{
|
||
btr_def def = fibheap_extract_min (all_btr_defs);
|
||
int min_cost = -fibheap_min_key (all_btr_defs);
|
||
if (migrate_btr_def (def, min_cost))
|
||
{
|
||
fibheap_insert (all_btr_defs, -def->cost, (void *) def);
|
||
if (dump_file)
|
||
{
|
||
fprintf (dump_file,
|
||
"Putting insn %d back on queue with priority %d\n",
|
||
INSN_UID (def->insn), def->cost);
|
||
}
|
||
}
|
||
else
|
||
BITMAP_FREE (def->live_range);
|
||
}
|
||
|
||
free (btrs_live);
|
||
free (btrs_live_at_end);
|
||
obstack_free (&migrate_btrl_obstack, NULL);
|
||
fibheap_delete (all_btr_defs);
|
||
}
|
||
|
||
void
|
||
branch_target_load_optimize (bool after_prologue_epilogue_gen)
|
||
{
|
||
enum reg_class class = targetm.branch_target_register_class ();
|
||
if (class != NO_REGS)
|
||
{
|
||
/* Initialize issue_rate. */
|
||
if (targetm.sched.issue_rate)
|
||
issue_rate = targetm.sched.issue_rate ();
|
||
else
|
||
issue_rate = 1;
|
||
|
||
/* Build the CFG for migrate_btr_defs. */
|
||
#if 1
|
||
/* This may or may not be needed, depending on where we
|
||
run this phase. */
|
||
cleanup_cfg (optimize ? CLEANUP_EXPENSIVE : 0);
|
||
#endif
|
||
|
||
life_analysis (0);
|
||
|
||
/* Dominator info is also needed for migrate_btr_def. */
|
||
calculate_dominance_info (CDI_DOMINATORS);
|
||
migrate_btr_defs (class,
|
||
(targetm.branch_target_register_callee_saved
|
||
(after_prologue_epilogue_gen)));
|
||
|
||
free_dominance_info (CDI_DOMINATORS);
|
||
|
||
update_life_info (NULL, UPDATE_LIFE_GLOBAL_RM_NOTES,
|
||
PROP_DEATH_NOTES | PROP_REG_INFO);
|
||
}
|
||
}
|
||
|
||
static bool
|
||
gate_handle_branch_target_load_optimize (void)
|
||
{
|
||
return (optimize > 0 && flag_branch_target_load_optimize2);
|
||
}
|
||
|
||
|
||
static unsigned int
|
||
rest_of_handle_branch_target_load_optimize (void)
|
||
{
|
||
static int warned = 0;
|
||
|
||
/* Leave this a warning for now so that it is possible to experiment
|
||
with running this pass twice. In 3.6, we should either make this
|
||
an error, or use separate dump files. */
|
||
if (flag_branch_target_load_optimize
|
||
&& flag_branch_target_load_optimize2
|
||
&& !warned)
|
||
{
|
||
warning (0, "branch target register load optimization is not intended "
|
||
"to be run twice");
|
||
|
||
warned = 1;
|
||
}
|
||
|
||
branch_target_load_optimize (epilogue_completed);
|
||
return 0;
|
||
}
|
||
|
||
struct tree_opt_pass pass_branch_target_load_optimize =
|
||
{
|
||
"btl", /* name */
|
||
gate_handle_branch_target_load_optimize, /* gate */
|
||
rest_of_handle_branch_target_load_optimize, /* execute */
|
||
NULL, /* sub */
|
||
NULL, /* next */
|
||
0, /* static_pass_number */
|
||
0, /* tv_id */
|
||
0, /* properties_required */
|
||
0, /* properties_provided */
|
||
0, /* properties_destroyed */
|
||
0, /* todo_flags_start */
|
||
TODO_dump_func |
|
||
TODO_ggc_collect, /* todo_flags_finish */
|
||
'd' /* letter */
|
||
};
|
||
|