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2361 lines
64 KiB
C
2361 lines
64 KiB
C
/* Scalar Replacement of Aggregates (SRA) converts some structure
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references into scalar references, exposing them to the scalar
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optimizers.
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Copyright (C) 2003, 2004, 2005, 2006, 2007
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Free Software Foundation, Inc.
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Contributed by Diego Novillo <dnovillo@redhat.com>
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||
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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 the terms of the GNU General Public License as published by the
|
||
Free Software Foundation; either version 2, or (at your option) any
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||
later version.
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GCC is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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||
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
||
for more details.
|
||
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||
You should have received a copy of the GNU General Public License
|
||
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 "ggc.h"
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#include "tree.h"
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/* These RTL headers are needed for basic-block.h. */
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#include "rtl.h"
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#include "tm_p.h"
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#include "hard-reg-set.h"
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||
#include "basic-block.h"
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||
#include "diagnostic.h"
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||
#include "langhooks.h"
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||
#include "tree-inline.h"
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||
#include "tree-flow.h"
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||
#include "tree-gimple.h"
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||
#include "tree-dump.h"
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||
#include "tree-pass.h"
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#include "timevar.h"
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#include "flags.h"
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||
#include "bitmap.h"
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#include "obstack.h"
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||
#include "target.h"
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||
/* expr.h is needed for MOVE_RATIO. */
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||
#include "expr.h"
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||
#include "params.h"
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||
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||
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||
/* This object of this pass is to replace a non-addressable aggregate with a
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set of independent variables. Most of the time, all of these variables
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||
will be scalars. But a secondary objective is to break up larger
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||
aggregates into smaller aggregates. In the process we may find that some
|
||
bits of the larger aggregate can be deleted as unreferenced.
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||
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||
This substitution is done globally. More localized substitutions would
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be the purvey of a load-store motion pass.
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The optimization proceeds in phases:
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(1) Identify variables that have types that are candidates for
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decomposition.
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(2) Scan the function looking for the ways these variables are used.
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In particular we're interested in the number of times a variable
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(or member) is needed as a complete unit, and the number of times
|
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a variable (or member) is copied.
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||
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(3) Based on the usage profile, instantiate substitution variables.
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||
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||
(4) Scan the function making replacements.
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*/
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||
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/* The set of todo flags to return from tree_sra. */
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static unsigned int todoflags;
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||
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||
/* The set of aggregate variables that are candidates for scalarization. */
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static bitmap sra_candidates;
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||
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||
/* Set of scalarizable PARM_DECLs that need copy-in operations at the
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beginning of the function. */
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||
static bitmap needs_copy_in;
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||
|
||
/* Sets of bit pairs that cache type decomposition and instantiation. */
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||
static bitmap sra_type_decomp_cache;
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||
static bitmap sra_type_inst_cache;
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||
|
||
/* One of these structures is created for each candidate aggregate and
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each (accessed) member or group of members of such an aggregate. */
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struct sra_elt
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{
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||
/* A tree of the elements. Used when we want to traverse everything. */
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||
struct sra_elt *parent;
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||
struct sra_elt *groups;
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struct sra_elt *children;
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||
struct sra_elt *sibling;
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||
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||
/* If this element is a root, then this is the VAR_DECL. If this is
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||
a sub-element, this is some token used to identify the reference.
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||
In the case of COMPONENT_REF, this is the FIELD_DECL. In the case
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||
of an ARRAY_REF, this is the (constant) index. In the case of an
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||
ARRAY_RANGE_REF, this is the (constant) RANGE_EXPR. In the case
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||
of a complex number, this is a zero or one. */
|
||
tree element;
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||
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||
/* The type of the element. */
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||
tree type;
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||
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||
/* A VAR_DECL, for any sub-element we've decided to replace. */
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||
tree replacement;
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||
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||
/* The number of times the element is referenced as a whole. I.e.
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||
given "a.b.c", this would be incremented for C, but not for A or B. */
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||
unsigned int n_uses;
|
||
|
||
/* The number of times the element is copied to or from another
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||
scalarizable element. */
|
||
unsigned int n_copies;
|
||
|
||
/* True if TYPE is scalar. */
|
||
bool is_scalar;
|
||
|
||
/* True if this element is a group of members of its parent. */
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||
bool is_group;
|
||
|
||
/* True if we saw something about this element that prevents scalarization,
|
||
such as non-constant indexing. */
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||
bool cannot_scalarize;
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||
|
||
/* True if we've decided that structure-to-structure assignment
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||
should happen via memcpy and not per-element. */
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||
bool use_block_copy;
|
||
|
||
/* True if everything under this element has been marked TREE_NO_WARNING. */
|
||
bool all_no_warning;
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||
|
||
/* A flag for use with/after random access traversals. */
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||
bool visited;
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||
};
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||
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||
#define IS_ELEMENT_FOR_GROUP(ELEMENT) (TREE_CODE (ELEMENT) == RANGE_EXPR)
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||
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||
#define FOR_EACH_ACTUAL_CHILD(CHILD, ELT) \
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for ((CHILD) = (ELT)->is_group \
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? next_child_for_group (NULL, (ELT)) \
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: (ELT)->children; \
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||
(CHILD); \
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||
(CHILD) = (ELT)->is_group \
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||
? next_child_for_group ((CHILD), (ELT)) \
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: (CHILD)->sibling)
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||
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||
/* Helper function for above macro. Return next child in group. */
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static struct sra_elt *
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||
next_child_for_group (struct sra_elt *child, struct sra_elt *group)
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{
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gcc_assert (group->is_group);
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||
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/* Find the next child in the parent. */
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if (child)
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child = child->sibling;
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else
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child = group->parent->children;
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/* Skip siblings that do not belong to the group. */
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while (child)
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{
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||
tree g_elt = group->element;
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if (TREE_CODE (g_elt) == RANGE_EXPR)
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{
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||
if (!tree_int_cst_lt (child->element, TREE_OPERAND (g_elt, 0))
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&& !tree_int_cst_lt (TREE_OPERAND (g_elt, 1), child->element))
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||
break;
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||
}
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||
else
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gcc_unreachable ();
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||
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||
child = child->sibling;
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||
}
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||
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return child;
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||
}
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/* Random access to the child of a parent is performed by hashing.
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This prevents quadratic behavior, and allows SRA to function
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reasonably on larger records. */
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static htab_t sra_map;
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/* All structures are allocated out of the following obstack. */
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static struct obstack sra_obstack;
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||
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/* Debugging functions. */
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static void dump_sra_elt_name (FILE *, struct sra_elt *);
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extern void debug_sra_elt_name (struct sra_elt *);
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/* Forward declarations. */
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static tree generate_element_ref (struct sra_elt *);
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/* Return true if DECL is an SRA candidate. */
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static bool
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is_sra_candidate_decl (tree decl)
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{
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return DECL_P (decl) && bitmap_bit_p (sra_candidates, DECL_UID (decl));
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}
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/* Return true if TYPE is a scalar type. */
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static bool
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is_sra_scalar_type (tree type)
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{
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enum tree_code code = TREE_CODE (type);
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return (code == INTEGER_TYPE || code == REAL_TYPE || code == VECTOR_TYPE
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|| code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
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|| code == POINTER_TYPE || code == OFFSET_TYPE
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|| code == REFERENCE_TYPE);
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}
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/* Return true if TYPE can be decomposed into a set of independent variables.
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Note that this doesn't imply that all elements of TYPE can be
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instantiated, just that if we decide to break up the type into
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separate pieces that it can be done. */
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bool
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sra_type_can_be_decomposed_p (tree type)
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{
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unsigned int cache = TYPE_UID (TYPE_MAIN_VARIANT (type)) * 2;
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tree t;
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/* Avoid searching the same type twice. */
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if (bitmap_bit_p (sra_type_decomp_cache, cache+0))
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return true;
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if (bitmap_bit_p (sra_type_decomp_cache, cache+1))
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return false;
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/* The type must have a definite nonzero size. */
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if (TYPE_SIZE (type) == NULL || TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST
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|| integer_zerop (TYPE_SIZE (type)))
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goto fail;
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/* The type must be a non-union aggregate. */
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switch (TREE_CODE (type))
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{
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case RECORD_TYPE:
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{
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bool saw_one_field = false;
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for (t = TYPE_FIELDS (type); t ; t = TREE_CHAIN (t))
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if (TREE_CODE (t) == FIELD_DECL)
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{
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/* Reject incorrectly represented bit fields. */
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if (DECL_BIT_FIELD (t)
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&& (tree_low_cst (DECL_SIZE (t), 1)
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!= TYPE_PRECISION (TREE_TYPE (t))))
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goto fail;
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saw_one_field = true;
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}
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/* Record types must have at least one field. */
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if (!saw_one_field)
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goto fail;
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}
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break;
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case ARRAY_TYPE:
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/* Array types must have a fixed lower and upper bound. */
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t = TYPE_DOMAIN (type);
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if (t == NULL)
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goto fail;
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if (TYPE_MIN_VALUE (t) == NULL || !TREE_CONSTANT (TYPE_MIN_VALUE (t)))
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goto fail;
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if (TYPE_MAX_VALUE (t) == NULL || !TREE_CONSTANT (TYPE_MAX_VALUE (t)))
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goto fail;
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break;
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case COMPLEX_TYPE:
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break;
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default:
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goto fail;
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}
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bitmap_set_bit (sra_type_decomp_cache, cache+0);
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return true;
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fail:
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bitmap_set_bit (sra_type_decomp_cache, cache+1);
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return false;
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}
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/* Return true if DECL can be decomposed into a set of independent
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(though not necessarily scalar) variables. */
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static bool
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decl_can_be_decomposed_p (tree var)
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{
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/* Early out for scalars. */
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if (is_sra_scalar_type (TREE_TYPE (var)))
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return false;
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/* The variable must not be aliased. */
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if (!is_gimple_non_addressable (var))
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{
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if (dump_file && (dump_flags & TDF_DETAILS))
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{
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fprintf (dump_file, "Cannot scalarize variable ");
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print_generic_expr (dump_file, var, dump_flags);
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fprintf (dump_file, " because it must live in memory\n");
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}
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return false;
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}
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/* The variable must not be volatile. */
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if (TREE_THIS_VOLATILE (var))
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{
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if (dump_file && (dump_flags & TDF_DETAILS))
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{
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fprintf (dump_file, "Cannot scalarize variable ");
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print_generic_expr (dump_file, var, dump_flags);
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fprintf (dump_file, " because it is declared volatile\n");
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}
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return false;
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}
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||
/* We must be able to decompose the variable's type. */
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if (!sra_type_can_be_decomposed_p (TREE_TYPE (var)))
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{
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if (dump_file && (dump_flags & TDF_DETAILS))
|
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{
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fprintf (dump_file, "Cannot scalarize variable ");
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print_generic_expr (dump_file, var, dump_flags);
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fprintf (dump_file, " because its type cannot be decomposed\n");
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}
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||
return false;
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}
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||
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||
return true;
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||
}
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||
|
||
/* Return true if TYPE can be *completely* decomposed into scalars. */
|
||
|
||
static bool
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type_can_instantiate_all_elements (tree type)
|
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{
|
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if (is_sra_scalar_type (type))
|
||
return true;
|
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if (!sra_type_can_be_decomposed_p (type))
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return false;
|
||
|
||
switch (TREE_CODE (type))
|
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{
|
||
case RECORD_TYPE:
|
||
{
|
||
unsigned int cache = TYPE_UID (TYPE_MAIN_VARIANT (type)) * 2;
|
||
tree f;
|
||
|
||
if (bitmap_bit_p (sra_type_inst_cache, cache+0))
|
||
return true;
|
||
if (bitmap_bit_p (sra_type_inst_cache, cache+1))
|
||
return false;
|
||
|
||
for (f = TYPE_FIELDS (type); f ; f = TREE_CHAIN (f))
|
||
if (TREE_CODE (f) == FIELD_DECL)
|
||
{
|
||
if (!type_can_instantiate_all_elements (TREE_TYPE (f)))
|
||
{
|
||
bitmap_set_bit (sra_type_inst_cache, cache+1);
|
||
return false;
|
||
}
|
||
}
|
||
|
||
bitmap_set_bit (sra_type_inst_cache, cache+0);
|
||
return true;
|
||
}
|
||
|
||
case ARRAY_TYPE:
|
||
return type_can_instantiate_all_elements (TREE_TYPE (type));
|
||
|
||
case COMPLEX_TYPE:
|
||
return true;
|
||
|
||
default:
|
||
gcc_unreachable ();
|
||
}
|
||
}
|
||
|
||
/* Test whether ELT or some sub-element cannot be scalarized. */
|
||
|
||
static bool
|
||
can_completely_scalarize_p (struct sra_elt *elt)
|
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{
|
||
struct sra_elt *c;
|
||
|
||
if (elt->cannot_scalarize)
|
||
return false;
|
||
|
||
for (c = elt->children; c; c = c->sibling)
|
||
if (!can_completely_scalarize_p (c))
|
||
return false;
|
||
|
||
for (c = elt->groups; c; c = c->sibling)
|
||
if (!can_completely_scalarize_p (c))
|
||
return false;
|
||
|
||
return true;
|
||
}
|
||
|
||
|
||
/* A simplified tree hashing algorithm that only handles the types of
|
||
trees we expect to find in sra_elt->element. */
|
||
|
||
static hashval_t
|
||
sra_hash_tree (tree t)
|
||
{
|
||
hashval_t h;
|
||
|
||
switch (TREE_CODE (t))
|
||
{
|
||
case VAR_DECL:
|
||
case PARM_DECL:
|
||
case RESULT_DECL:
|
||
h = DECL_UID (t);
|
||
break;
|
||
|
||
case INTEGER_CST:
|
||
h = TREE_INT_CST_LOW (t) ^ TREE_INT_CST_HIGH (t);
|
||
break;
|
||
|
||
case RANGE_EXPR:
|
||
h = iterative_hash_expr (TREE_OPERAND (t, 0), 0);
|
||
h = iterative_hash_expr (TREE_OPERAND (t, 1), h);
|
||
break;
|
||
|
||
case FIELD_DECL:
|
||
/* We can have types that are compatible, but have different member
|
||
lists, so we can't hash fields by ID. Use offsets instead. */
|
||
h = iterative_hash_expr (DECL_FIELD_OFFSET (t), 0);
|
||
h = iterative_hash_expr (DECL_FIELD_BIT_OFFSET (t), h);
|
||
break;
|
||
|
||
default:
|
||
gcc_unreachable ();
|
||
}
|
||
|
||
return h;
|
||
}
|
||
|
||
/* Hash function for type SRA_PAIR. */
|
||
|
||
static hashval_t
|
||
sra_elt_hash (const void *x)
|
||
{
|
||
const struct sra_elt *e = x;
|
||
const struct sra_elt *p;
|
||
hashval_t h;
|
||
|
||
h = sra_hash_tree (e->element);
|
||
|
||
/* Take into account everything back up the chain. Given that chain
|
||
lengths are rarely very long, this should be acceptable. If we
|
||
truly identify this as a performance problem, it should work to
|
||
hash the pointer value "e->parent". */
|
||
for (p = e->parent; p ; p = p->parent)
|
||
h = (h * 65521) ^ sra_hash_tree (p->element);
|
||
|
||
return h;
|
||
}
|
||
|
||
/* Equality function for type SRA_PAIR. */
|
||
|
||
static int
|
||
sra_elt_eq (const void *x, const void *y)
|
||
{
|
||
const struct sra_elt *a = x;
|
||
const struct sra_elt *b = y;
|
||
tree ae, be;
|
||
|
||
if (a->parent != b->parent)
|
||
return false;
|
||
|
||
ae = a->element;
|
||
be = b->element;
|
||
|
||
if (ae == be)
|
||
return true;
|
||
if (TREE_CODE (ae) != TREE_CODE (be))
|
||
return false;
|
||
|
||
switch (TREE_CODE (ae))
|
||
{
|
||
case VAR_DECL:
|
||
case PARM_DECL:
|
||
case RESULT_DECL:
|
||
/* These are all pointer unique. */
|
||
return false;
|
||
|
||
case INTEGER_CST:
|
||
/* Integers are not pointer unique, so compare their values. */
|
||
return tree_int_cst_equal (ae, be);
|
||
|
||
case RANGE_EXPR:
|
||
return
|
||
tree_int_cst_equal (TREE_OPERAND (ae, 0), TREE_OPERAND (be, 0))
|
||
&& tree_int_cst_equal (TREE_OPERAND (ae, 1), TREE_OPERAND (be, 1));
|
||
|
||
case FIELD_DECL:
|
||
/* Fields are unique within a record, but not between
|
||
compatible records. */
|
||
if (DECL_FIELD_CONTEXT (ae) == DECL_FIELD_CONTEXT (be))
|
||
return false;
|
||
return fields_compatible_p (ae, be);
|
||
|
||
default:
|
||
gcc_unreachable ();
|
||
}
|
||
}
|
||
|
||
/* Create or return the SRA_ELT structure for CHILD in PARENT. PARENT
|
||
may be null, in which case CHILD must be a DECL. */
|
||
|
||
static struct sra_elt *
|
||
lookup_element (struct sra_elt *parent, tree child, tree type,
|
||
enum insert_option insert)
|
||
{
|
||
struct sra_elt dummy;
|
||
struct sra_elt **slot;
|
||
struct sra_elt *elt;
|
||
|
||
if (parent)
|
||
dummy.parent = parent->is_group ? parent->parent : parent;
|
||
else
|
||
dummy.parent = NULL;
|
||
dummy.element = child;
|
||
|
||
slot = (struct sra_elt **) htab_find_slot (sra_map, &dummy, insert);
|
||
if (!slot && insert == NO_INSERT)
|
||
return NULL;
|
||
|
||
elt = *slot;
|
||
if (!elt && insert == INSERT)
|
||
{
|
||
*slot = elt = obstack_alloc (&sra_obstack, sizeof (*elt));
|
||
memset (elt, 0, sizeof (*elt));
|
||
|
||
elt->parent = parent;
|
||
elt->element = child;
|
||
elt->type = type;
|
||
elt->is_scalar = is_sra_scalar_type (type);
|
||
|
||
if (parent)
|
||
{
|
||
if (IS_ELEMENT_FOR_GROUP (elt->element))
|
||
{
|
||
elt->is_group = true;
|
||
elt->sibling = parent->groups;
|
||
parent->groups = elt;
|
||
}
|
||
else
|
||
{
|
||
elt->sibling = parent->children;
|
||
parent->children = elt;
|
||
}
|
||
}
|
||
|
||
/* If this is a parameter, then if we want to scalarize, we have
|
||
one copy from the true function parameter. Count it now. */
|
||
if (TREE_CODE (child) == PARM_DECL)
|
||
{
|
||
elt->n_copies = 1;
|
||
bitmap_set_bit (needs_copy_in, DECL_UID (child));
|
||
}
|
||
}
|
||
|
||
return elt;
|
||
}
|
||
|
||
/* Create or return the SRA_ELT structure for EXPR if the expression
|
||
refers to a scalarizable variable. */
|
||
|
||
static struct sra_elt *
|
||
maybe_lookup_element_for_expr (tree expr)
|
||
{
|
||
struct sra_elt *elt;
|
||
tree child;
|
||
|
||
switch (TREE_CODE (expr))
|
||
{
|
||
case VAR_DECL:
|
||
case PARM_DECL:
|
||
case RESULT_DECL:
|
||
if (is_sra_candidate_decl (expr))
|
||
return lookup_element (NULL, expr, TREE_TYPE (expr), INSERT);
|
||
return NULL;
|
||
|
||
case ARRAY_REF:
|
||
/* We can't scalarize variable array indices. */
|
||
if (in_array_bounds_p (expr))
|
||
child = TREE_OPERAND (expr, 1);
|
||
else
|
||
return NULL;
|
||
break;
|
||
|
||
case ARRAY_RANGE_REF:
|
||
/* We can't scalarize variable array indices. */
|
||
if (range_in_array_bounds_p (expr))
|
||
{
|
||
tree domain = TYPE_DOMAIN (TREE_TYPE (expr));
|
||
child = build2 (RANGE_EXPR, integer_type_node,
|
||
TYPE_MIN_VALUE (domain), TYPE_MAX_VALUE (domain));
|
||
}
|
||
else
|
||
return NULL;
|
||
break;
|
||
|
||
case COMPONENT_REF:
|
||
/* Don't look through unions. */
|
||
if (TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) != RECORD_TYPE)
|
||
return NULL;
|
||
child = TREE_OPERAND (expr, 1);
|
||
break;
|
||
|
||
case REALPART_EXPR:
|
||
child = integer_zero_node;
|
||
break;
|
||
case IMAGPART_EXPR:
|
||
child = integer_one_node;
|
||
break;
|
||
|
||
default:
|
||
return NULL;
|
||
}
|
||
|
||
elt = maybe_lookup_element_for_expr (TREE_OPERAND (expr, 0));
|
||
if (elt)
|
||
return lookup_element (elt, child, TREE_TYPE (expr), INSERT);
|
||
return NULL;
|
||
}
|
||
|
||
|
||
/* Functions to walk just enough of the tree to see all scalarizable
|
||
references, and categorize them. */
|
||
|
||
/* A set of callbacks for phases 2 and 4. They'll be invoked for the
|
||
various kinds of references seen. In all cases, *BSI is an iterator
|
||
pointing to the statement being processed. */
|
||
struct sra_walk_fns
|
||
{
|
||
/* Invoked when ELT is required as a unit. Note that ELT might refer to
|
||
a leaf node, in which case this is a simple scalar reference. *EXPR_P
|
||
points to the location of the expression. IS_OUTPUT is true if this
|
||
is a left-hand-side reference. USE_ALL is true if we saw something we
|
||
couldn't quite identify and had to force the use of the entire object. */
|
||
void (*use) (struct sra_elt *elt, tree *expr_p,
|
||
block_stmt_iterator *bsi, bool is_output, bool use_all);
|
||
|
||
/* Invoked when we have a copy between two scalarizable references. */
|
||
void (*copy) (struct sra_elt *lhs_elt, struct sra_elt *rhs_elt,
|
||
block_stmt_iterator *bsi);
|
||
|
||
/* Invoked when ELT is initialized from a constant. VALUE may be NULL,
|
||
in which case it should be treated as an empty CONSTRUCTOR. */
|
||
void (*init) (struct sra_elt *elt, tree value, block_stmt_iterator *bsi);
|
||
|
||
/* Invoked when we have a copy between one scalarizable reference ELT
|
||
and one non-scalarizable reference OTHER without side-effects.
|
||
IS_OUTPUT is true if ELT is on the left-hand side. */
|
||
void (*ldst) (struct sra_elt *elt, tree other,
|
||
block_stmt_iterator *bsi, bool is_output);
|
||
|
||
/* True during phase 2, false during phase 4. */
|
||
/* ??? This is a hack. */
|
||
bool initial_scan;
|
||
};
|
||
|
||
#ifdef ENABLE_CHECKING
|
||
/* Invoked via walk_tree, if *TP contains a candidate decl, return it. */
|
||
|
||
static tree
|
||
sra_find_candidate_decl (tree *tp, int *walk_subtrees,
|
||
void *data ATTRIBUTE_UNUSED)
|
||
{
|
||
tree t = *tp;
|
||
enum tree_code code = TREE_CODE (t);
|
||
|
||
if (code == VAR_DECL || code == PARM_DECL || code == RESULT_DECL)
|
||
{
|
||
*walk_subtrees = 0;
|
||
if (is_sra_candidate_decl (t))
|
||
return t;
|
||
}
|
||
else if (TYPE_P (t))
|
||
*walk_subtrees = 0;
|
||
|
||
return NULL;
|
||
}
|
||
#endif
|
||
|
||
/* Walk most expressions looking for a scalarizable aggregate.
|
||
If we find one, invoke FNS->USE. */
|
||
|
||
static void
|
||
sra_walk_expr (tree *expr_p, block_stmt_iterator *bsi, bool is_output,
|
||
const struct sra_walk_fns *fns)
|
||
{
|
||
tree expr = *expr_p;
|
||
tree inner = expr;
|
||
bool disable_scalarization = false;
|
||
bool use_all_p = false;
|
||
|
||
/* We're looking to collect a reference expression between EXPR and INNER,
|
||
such that INNER is a scalarizable decl and all other nodes through EXPR
|
||
are references that we can scalarize. If we come across something that
|
||
we can't scalarize, we reset EXPR. This has the effect of making it
|
||
appear that we're referring to the larger expression as a whole. */
|
||
|
||
while (1)
|
||
switch (TREE_CODE (inner))
|
||
{
|
||
case VAR_DECL:
|
||
case PARM_DECL:
|
||
case RESULT_DECL:
|
||
/* If there is a scalarizable decl at the bottom, then process it. */
|
||
if (is_sra_candidate_decl (inner))
|
||
{
|
||
struct sra_elt *elt = maybe_lookup_element_for_expr (expr);
|
||
if (disable_scalarization)
|
||
elt->cannot_scalarize = true;
|
||
else
|
||
fns->use (elt, expr_p, bsi, is_output, use_all_p);
|
||
}
|
||
return;
|
||
|
||
case ARRAY_REF:
|
||
/* Non-constant index means any member may be accessed. Prevent the
|
||
expression from being scalarized. If we were to treat this as a
|
||
reference to the whole array, we can wind up with a single dynamic
|
||
index reference inside a loop being overridden by several constant
|
||
index references during loop setup. It's possible that this could
|
||
be avoided by using dynamic usage counts based on BB trip counts
|
||
(based on loop analysis or profiling), but that hardly seems worth
|
||
the effort. */
|
||
/* ??? Hack. Figure out how to push this into the scan routines
|
||
without duplicating too much code. */
|
||
if (!in_array_bounds_p (inner))
|
||
{
|
||
disable_scalarization = true;
|
||
goto use_all;
|
||
}
|
||
/* ??? Are we assured that non-constant bounds and stride will have
|
||
the same value everywhere? I don't think Fortran will... */
|
||
if (TREE_OPERAND (inner, 2) || TREE_OPERAND (inner, 3))
|
||
goto use_all;
|
||
inner = TREE_OPERAND (inner, 0);
|
||
break;
|
||
|
||
case ARRAY_RANGE_REF:
|
||
if (!range_in_array_bounds_p (inner))
|
||
{
|
||
disable_scalarization = true;
|
||
goto use_all;
|
||
}
|
||
/* ??? See above non-constant bounds and stride . */
|
||
if (TREE_OPERAND (inner, 2) || TREE_OPERAND (inner, 3))
|
||
goto use_all;
|
||
inner = TREE_OPERAND (inner, 0);
|
||
break;
|
||
|
||
case COMPONENT_REF:
|
||
/* A reference to a union member constitutes a reference to the
|
||
entire union. */
|
||
if (TREE_CODE (TREE_TYPE (TREE_OPERAND (inner, 0))) != RECORD_TYPE)
|
||
goto use_all;
|
||
/* ??? See above re non-constant stride. */
|
||
if (TREE_OPERAND (inner, 2))
|
||
goto use_all;
|
||
inner = TREE_OPERAND (inner, 0);
|
||
break;
|
||
|
||
case REALPART_EXPR:
|
||
case IMAGPART_EXPR:
|
||
inner = TREE_OPERAND (inner, 0);
|
||
break;
|
||
|
||
case BIT_FIELD_REF:
|
||
/* A bit field reference (access to *multiple* fields simultaneously)
|
||
is not currently scalarized. Consider this an access to the
|
||
complete outer element, to which walk_tree will bring us next. */
|
||
goto use_all;
|
||
|
||
case VIEW_CONVERT_EXPR:
|
||
case NOP_EXPR:
|
||
/* Similarly, a view/nop explicitly wants to look at an object in a
|
||
type other than the one we've scalarized. */
|
||
goto use_all;
|
||
|
||
case WITH_SIZE_EXPR:
|
||
/* This is a transparent wrapper. The entire inner expression really
|
||
is being used. */
|
||
goto use_all;
|
||
|
||
use_all:
|
||
expr_p = &TREE_OPERAND (inner, 0);
|
||
inner = expr = *expr_p;
|
||
use_all_p = true;
|
||
break;
|
||
|
||
default:
|
||
#ifdef ENABLE_CHECKING
|
||
/* Validate that we're not missing any references. */
|
||
gcc_assert (!walk_tree (&inner, sra_find_candidate_decl, NULL, NULL));
|
||
#endif
|
||
return;
|
||
}
|
||
}
|
||
|
||
/* Walk a TREE_LIST of values looking for scalarizable aggregates.
|
||
If we find one, invoke FNS->USE. */
|
||
|
||
static void
|
||
sra_walk_tree_list (tree list, block_stmt_iterator *bsi, bool is_output,
|
||
const struct sra_walk_fns *fns)
|
||
{
|
||
tree op;
|
||
for (op = list; op ; op = TREE_CHAIN (op))
|
||
sra_walk_expr (&TREE_VALUE (op), bsi, is_output, fns);
|
||
}
|
||
|
||
/* Walk the arguments of a CALL_EXPR looking for scalarizable aggregates.
|
||
If we find one, invoke FNS->USE. */
|
||
|
||
static void
|
||
sra_walk_call_expr (tree expr, block_stmt_iterator *bsi,
|
||
const struct sra_walk_fns *fns)
|
||
{
|
||
sra_walk_tree_list (TREE_OPERAND (expr, 1), bsi, false, fns);
|
||
}
|
||
|
||
/* Walk the inputs and outputs of an ASM_EXPR looking for scalarizable
|
||
aggregates. If we find one, invoke FNS->USE. */
|
||
|
||
static void
|
||
sra_walk_asm_expr (tree expr, block_stmt_iterator *bsi,
|
||
const struct sra_walk_fns *fns)
|
||
{
|
||
sra_walk_tree_list (ASM_INPUTS (expr), bsi, false, fns);
|
||
sra_walk_tree_list (ASM_OUTPUTS (expr), bsi, true, fns);
|
||
}
|
||
|
||
/* Walk a MODIFY_EXPR and categorize the assignment appropriately. */
|
||
|
||
static void
|
||
sra_walk_modify_expr (tree expr, block_stmt_iterator *bsi,
|
||
const struct sra_walk_fns *fns)
|
||
{
|
||
struct sra_elt *lhs_elt, *rhs_elt;
|
||
tree lhs, rhs;
|
||
|
||
lhs = TREE_OPERAND (expr, 0);
|
||
rhs = TREE_OPERAND (expr, 1);
|
||
lhs_elt = maybe_lookup_element_for_expr (lhs);
|
||
rhs_elt = maybe_lookup_element_for_expr (rhs);
|
||
|
||
/* If both sides are scalarizable, this is a COPY operation. */
|
||
if (lhs_elt && rhs_elt)
|
||
{
|
||
fns->copy (lhs_elt, rhs_elt, bsi);
|
||
return;
|
||
}
|
||
|
||
/* If the RHS is scalarizable, handle it. There are only two cases. */
|
||
if (rhs_elt)
|
||
{
|
||
if (!rhs_elt->is_scalar && !TREE_SIDE_EFFECTS (lhs))
|
||
fns->ldst (rhs_elt, lhs, bsi, false);
|
||
else
|
||
fns->use (rhs_elt, &TREE_OPERAND (expr, 1), bsi, false, false);
|
||
}
|
||
|
||
/* If it isn't scalarizable, there may be scalarizable variables within, so
|
||
check for a call or else walk the RHS to see if we need to do any
|
||
copy-in operations. We need to do it before the LHS is scalarized so
|
||
that the statements get inserted in the proper place, before any
|
||
copy-out operations. */
|
||
else
|
||
{
|
||
tree call = get_call_expr_in (rhs);
|
||
if (call)
|
||
sra_walk_call_expr (call, bsi, fns);
|
||
else
|
||
sra_walk_expr (&TREE_OPERAND (expr, 1), bsi, false, fns);
|
||
}
|
||
|
||
/* Likewise, handle the LHS being scalarizable. We have cases similar
|
||
to those above, but also want to handle RHS being constant. */
|
||
if (lhs_elt)
|
||
{
|
||
/* If this is an assignment from a constant, or constructor, then
|
||
we have access to all of the elements individually. Invoke INIT. */
|
||
if (TREE_CODE (rhs) == COMPLEX_EXPR
|
||
|| TREE_CODE (rhs) == COMPLEX_CST
|
||
|| TREE_CODE (rhs) == CONSTRUCTOR)
|
||
fns->init (lhs_elt, rhs, bsi);
|
||
|
||
/* If this is an assignment from read-only memory, treat this as if
|
||
we'd been passed the constructor directly. Invoke INIT. */
|
||
else if (TREE_CODE (rhs) == VAR_DECL
|
||
&& TREE_STATIC (rhs)
|
||
&& TREE_READONLY (rhs)
|
||
&& targetm.binds_local_p (rhs))
|
||
fns->init (lhs_elt, DECL_INITIAL (rhs), bsi);
|
||
|
||
/* If this is a copy from a non-scalarizable lvalue, invoke LDST.
|
||
The lvalue requirement prevents us from trying to directly scalarize
|
||
the result of a function call. Which would result in trying to call
|
||
the function multiple times, and other evil things. */
|
||
else if (!lhs_elt->is_scalar
|
||
&& !TREE_SIDE_EFFECTS (rhs) && is_gimple_addressable (rhs))
|
||
fns->ldst (lhs_elt, rhs, bsi, true);
|
||
|
||
/* Otherwise we're being used in some context that requires the
|
||
aggregate to be seen as a whole. Invoke USE. */
|
||
else
|
||
fns->use (lhs_elt, &TREE_OPERAND (expr, 0), bsi, true, false);
|
||
}
|
||
|
||
/* Similarly to above, LHS_ELT being null only means that the LHS as a
|
||
whole is not a scalarizable reference. There may be occurrences of
|
||
scalarizable variables within, which implies a USE. */
|
||
else
|
||
sra_walk_expr (&TREE_OPERAND (expr, 0), bsi, true, fns);
|
||
}
|
||
|
||
/* Entry point to the walk functions. Search the entire function,
|
||
invoking the callbacks in FNS on each of the references to
|
||
scalarizable variables. */
|
||
|
||
static void
|
||
sra_walk_function (const struct sra_walk_fns *fns)
|
||
{
|
||
basic_block bb;
|
||
block_stmt_iterator si, ni;
|
||
|
||
/* ??? Phase 4 could derive some benefit to walking the function in
|
||
dominator tree order. */
|
||
|
||
FOR_EACH_BB (bb)
|
||
for (si = bsi_start (bb); !bsi_end_p (si); si = ni)
|
||
{
|
||
tree stmt, t;
|
||
stmt_ann_t ann;
|
||
|
||
stmt = bsi_stmt (si);
|
||
ann = stmt_ann (stmt);
|
||
|
||
ni = si;
|
||
bsi_next (&ni);
|
||
|
||
/* If the statement has no virtual operands, then it doesn't
|
||
make any structure references that we care about. */
|
||
if (ZERO_SSA_OPERANDS (stmt, (SSA_OP_VIRTUAL_DEFS | SSA_OP_VUSE)))
|
||
continue;
|
||
|
||
switch (TREE_CODE (stmt))
|
||
{
|
||
case RETURN_EXPR:
|
||
/* If we have "return <retval>" then the return value is
|
||
already exposed for our pleasure. Walk it as a USE to
|
||
force all the components back in place for the return.
|
||
|
||
If we have an embedded assignment, then <retval> is of
|
||
a type that gets returned in registers in this ABI, and
|
||
we do not wish to extend their lifetimes. Treat this
|
||
as a USE of the variable on the RHS of this assignment. */
|
||
|
||
t = TREE_OPERAND (stmt, 0);
|
||
if (TREE_CODE (t) == MODIFY_EXPR)
|
||
sra_walk_expr (&TREE_OPERAND (t, 1), &si, false, fns);
|
||
else
|
||
sra_walk_expr (&TREE_OPERAND (stmt, 0), &si, false, fns);
|
||
break;
|
||
|
||
case MODIFY_EXPR:
|
||
sra_walk_modify_expr (stmt, &si, fns);
|
||
break;
|
||
case CALL_EXPR:
|
||
sra_walk_call_expr (stmt, &si, fns);
|
||
break;
|
||
case ASM_EXPR:
|
||
sra_walk_asm_expr (stmt, &si, fns);
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Phase One: Scan all referenced variables in the program looking for
|
||
structures that could be decomposed. */
|
||
|
||
static bool
|
||
find_candidates_for_sra (void)
|
||
{
|
||
bool any_set = false;
|
||
tree var;
|
||
referenced_var_iterator rvi;
|
||
|
||
FOR_EACH_REFERENCED_VAR (var, rvi)
|
||
{
|
||
if (decl_can_be_decomposed_p (var))
|
||
{
|
||
bitmap_set_bit (sra_candidates, DECL_UID (var));
|
||
any_set = true;
|
||
}
|
||
}
|
||
|
||
return any_set;
|
||
}
|
||
|
||
|
||
/* Phase Two: Scan all references to scalarizable variables. Count the
|
||
number of times they are used or copied respectively. */
|
||
|
||
/* Callbacks to fill in SRA_WALK_FNS. Everything but USE is
|
||
considered a copy, because we can decompose the reference such that
|
||
the sub-elements needn't be contiguous. */
|
||
|
||
static void
|
||
scan_use (struct sra_elt *elt, tree *expr_p ATTRIBUTE_UNUSED,
|
||
block_stmt_iterator *bsi ATTRIBUTE_UNUSED,
|
||
bool is_output ATTRIBUTE_UNUSED, bool use_all ATTRIBUTE_UNUSED)
|
||
{
|
||
elt->n_uses += 1;
|
||
}
|
||
|
||
static void
|
||
scan_copy (struct sra_elt *lhs_elt, struct sra_elt *rhs_elt,
|
||
block_stmt_iterator *bsi ATTRIBUTE_UNUSED)
|
||
{
|
||
lhs_elt->n_copies += 1;
|
||
rhs_elt->n_copies += 1;
|
||
}
|
||
|
||
static void
|
||
scan_init (struct sra_elt *lhs_elt, tree rhs ATTRIBUTE_UNUSED,
|
||
block_stmt_iterator *bsi ATTRIBUTE_UNUSED)
|
||
{
|
||
lhs_elt->n_copies += 1;
|
||
}
|
||
|
||
static void
|
||
scan_ldst (struct sra_elt *elt, tree other ATTRIBUTE_UNUSED,
|
||
block_stmt_iterator *bsi ATTRIBUTE_UNUSED,
|
||
bool is_output ATTRIBUTE_UNUSED)
|
||
{
|
||
elt->n_copies += 1;
|
||
}
|
||
|
||
/* Dump the values we collected during the scanning phase. */
|
||
|
||
static void
|
||
scan_dump (struct sra_elt *elt)
|
||
{
|
||
struct sra_elt *c;
|
||
|
||
dump_sra_elt_name (dump_file, elt);
|
||
fprintf (dump_file, ": n_uses=%u n_copies=%u\n", elt->n_uses, elt->n_copies);
|
||
|
||
for (c = elt->children; c ; c = c->sibling)
|
||
scan_dump (c);
|
||
|
||
for (c = elt->groups; c ; c = c->sibling)
|
||
scan_dump (c);
|
||
}
|
||
|
||
/* Entry point to phase 2. Scan the entire function, building up
|
||
scalarization data structures, recording copies and uses. */
|
||
|
||
static void
|
||
scan_function (void)
|
||
{
|
||
static const struct sra_walk_fns fns = {
|
||
scan_use, scan_copy, scan_init, scan_ldst, true
|
||
};
|
||
bitmap_iterator bi;
|
||
|
||
sra_walk_function (&fns);
|
||
|
||
if (dump_file && (dump_flags & TDF_DETAILS))
|
||
{
|
||
unsigned i;
|
||
|
||
fputs ("\nScan results:\n", dump_file);
|
||
EXECUTE_IF_SET_IN_BITMAP (sra_candidates, 0, i, bi)
|
||
{
|
||
tree var = referenced_var (i);
|
||
struct sra_elt *elt = lookup_element (NULL, var, NULL, NO_INSERT);
|
||
if (elt)
|
||
scan_dump (elt);
|
||
}
|
||
fputc ('\n', dump_file);
|
||
}
|
||
}
|
||
|
||
/* Phase Three: Make decisions about which variables to scalarize, if any.
|
||
All elements to be scalarized have replacement variables made for them. */
|
||
|
||
/* A subroutine of build_element_name. Recursively build the element
|
||
name on the obstack. */
|
||
|
||
static void
|
||
build_element_name_1 (struct sra_elt *elt)
|
||
{
|
||
tree t;
|
||
char buffer[32];
|
||
|
||
if (elt->parent)
|
||
{
|
||
build_element_name_1 (elt->parent);
|
||
obstack_1grow (&sra_obstack, '$');
|
||
|
||
if (TREE_CODE (elt->parent->type) == COMPLEX_TYPE)
|
||
{
|
||
if (elt->element == integer_zero_node)
|
||
obstack_grow (&sra_obstack, "real", 4);
|
||
else
|
||
obstack_grow (&sra_obstack, "imag", 4);
|
||
return;
|
||
}
|
||
}
|
||
|
||
t = elt->element;
|
||
if (TREE_CODE (t) == INTEGER_CST)
|
||
{
|
||
/* ??? Eh. Don't bother doing double-wide printing. */
|
||
sprintf (buffer, HOST_WIDE_INT_PRINT_DEC, TREE_INT_CST_LOW (t));
|
||
obstack_grow (&sra_obstack, buffer, strlen (buffer));
|
||
}
|
||
else
|
||
{
|
||
tree name = DECL_NAME (t);
|
||
if (name)
|
||
obstack_grow (&sra_obstack, IDENTIFIER_POINTER (name),
|
||
IDENTIFIER_LENGTH (name));
|
||
else
|
||
{
|
||
sprintf (buffer, "D%u", DECL_UID (t));
|
||
obstack_grow (&sra_obstack, buffer, strlen (buffer));
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Construct a pretty variable name for an element's replacement variable.
|
||
The name is built on the obstack. */
|
||
|
||
static char *
|
||
build_element_name (struct sra_elt *elt)
|
||
{
|
||
build_element_name_1 (elt);
|
||
obstack_1grow (&sra_obstack, '\0');
|
||
return XOBFINISH (&sra_obstack, char *);
|
||
}
|
||
|
||
/* Instantiate an element as an independent variable. */
|
||
|
||
static void
|
||
instantiate_element (struct sra_elt *elt)
|
||
{
|
||
struct sra_elt *base_elt;
|
||
tree var, base;
|
||
|
||
for (base_elt = elt; base_elt->parent; base_elt = base_elt->parent)
|
||
continue;
|
||
base = base_elt->element;
|
||
|
||
elt->replacement = var = make_rename_temp (elt->type, "SR");
|
||
DECL_SOURCE_LOCATION (var) = DECL_SOURCE_LOCATION (base);
|
||
DECL_ARTIFICIAL (var) = 1;
|
||
|
||
if (TREE_THIS_VOLATILE (elt->type))
|
||
{
|
||
TREE_THIS_VOLATILE (var) = 1;
|
||
TREE_SIDE_EFFECTS (var) = 1;
|
||
}
|
||
|
||
if (DECL_NAME (base) && !DECL_IGNORED_P (base))
|
||
{
|
||
char *pretty_name = build_element_name (elt);
|
||
DECL_NAME (var) = get_identifier (pretty_name);
|
||
obstack_free (&sra_obstack, pretty_name);
|
||
|
||
SET_DECL_DEBUG_EXPR (var, generate_element_ref (elt));
|
||
DECL_DEBUG_EXPR_IS_FROM (var) = 1;
|
||
|
||
DECL_IGNORED_P (var) = 0;
|
||
TREE_NO_WARNING (var) = TREE_NO_WARNING (base);
|
||
}
|
||
else
|
||
{
|
||
DECL_IGNORED_P (var) = 1;
|
||
/* ??? We can't generate any warning that would be meaningful. */
|
||
TREE_NO_WARNING (var) = 1;
|
||
}
|
||
|
||
if (dump_file)
|
||
{
|
||
fputs (" ", dump_file);
|
||
dump_sra_elt_name (dump_file, elt);
|
||
fputs (" -> ", dump_file);
|
||
print_generic_expr (dump_file, var, dump_flags);
|
||
fputc ('\n', dump_file);
|
||
}
|
||
}
|
||
|
||
/* Make one pass across an element tree deciding whether or not it's
|
||
profitable to instantiate individual leaf scalars.
|
||
|
||
PARENT_USES and PARENT_COPIES are the sum of the N_USES and N_COPIES
|
||
fields all the way up the tree. */
|
||
|
||
static void
|
||
decide_instantiation_1 (struct sra_elt *elt, unsigned int parent_uses,
|
||
unsigned int parent_copies)
|
||
{
|
||
if (dump_file && !elt->parent)
|
||
{
|
||
fputs ("Initial instantiation for ", dump_file);
|
||
dump_sra_elt_name (dump_file, elt);
|
||
fputc ('\n', dump_file);
|
||
}
|
||
|
||
if (elt->cannot_scalarize)
|
||
return;
|
||
|
||
if (elt->is_scalar)
|
||
{
|
||
/* The decision is simple: instantiate if we're used more frequently
|
||
than the parent needs to be seen as a complete unit. */
|
||
if (elt->n_uses + elt->n_copies + parent_copies > parent_uses)
|
||
instantiate_element (elt);
|
||
}
|
||
else
|
||
{
|
||
struct sra_elt *c, *group;
|
||
unsigned int this_uses = elt->n_uses + parent_uses;
|
||
unsigned int this_copies = elt->n_copies + parent_copies;
|
||
|
||
/* Consider groups of sub-elements as weighing in favour of
|
||
instantiation whatever their size. */
|
||
for (group = elt->groups; group ; group = group->sibling)
|
||
FOR_EACH_ACTUAL_CHILD (c, group)
|
||
{
|
||
c->n_uses += group->n_uses;
|
||
c->n_copies += group->n_copies;
|
||
}
|
||
|
||
for (c = elt->children; c ; c = c->sibling)
|
||
decide_instantiation_1 (c, this_uses, this_copies);
|
||
}
|
||
}
|
||
|
||
/* Compute the size and number of all instantiated elements below ELT.
|
||
We will only care about this if the size of the complete structure
|
||
fits in a HOST_WIDE_INT, so we don't have to worry about overflow. */
|
||
|
||
static unsigned int
|
||
sum_instantiated_sizes (struct sra_elt *elt, unsigned HOST_WIDE_INT *sizep)
|
||
{
|
||
if (elt->replacement)
|
||
{
|
||
*sizep += TREE_INT_CST_LOW (TYPE_SIZE_UNIT (elt->type));
|
||
return 1;
|
||
}
|
||
else
|
||
{
|
||
struct sra_elt *c;
|
||
unsigned int count = 0;
|
||
|
||
for (c = elt->children; c ; c = c->sibling)
|
||
count += sum_instantiated_sizes (c, sizep);
|
||
|
||
return count;
|
||
}
|
||
}
|
||
|
||
/* Instantiate fields in ELT->TYPE that are not currently present as
|
||
children of ELT. */
|
||
|
||
static void instantiate_missing_elements (struct sra_elt *elt);
|
||
|
||
static void
|
||
instantiate_missing_elements_1 (struct sra_elt *elt, tree child, tree type)
|
||
{
|
||
struct sra_elt *sub = lookup_element (elt, child, type, INSERT);
|
||
if (sub->is_scalar)
|
||
{
|
||
if (sub->replacement == NULL)
|
||
instantiate_element (sub);
|
||
}
|
||
else
|
||
instantiate_missing_elements (sub);
|
||
}
|
||
|
||
static void
|
||
instantiate_missing_elements (struct sra_elt *elt)
|
||
{
|
||
tree type = elt->type;
|
||
|
||
switch (TREE_CODE (type))
|
||
{
|
||
case RECORD_TYPE:
|
||
{
|
||
tree f;
|
||
for (f = TYPE_FIELDS (type); f ; f = TREE_CHAIN (f))
|
||
if (TREE_CODE (f) == FIELD_DECL)
|
||
{
|
||
tree field_type = TREE_TYPE (f);
|
||
|
||
/* canonicalize_component_ref() unwidens some bit-field
|
||
types (not marked as DECL_BIT_FIELD in C++), so we
|
||
must do the same, lest we may introduce type
|
||
mismatches. */
|
||
if (INTEGRAL_TYPE_P (field_type)
|
||
&& DECL_MODE (f) != TYPE_MODE (field_type))
|
||
field_type = TREE_TYPE (get_unwidened (build3 (COMPONENT_REF,
|
||
field_type,
|
||
elt->element,
|
||
f, NULL_TREE),
|
||
NULL_TREE));
|
||
|
||
instantiate_missing_elements_1 (elt, f, field_type);
|
||
}
|
||
break;
|
||
}
|
||
|
||
case ARRAY_TYPE:
|
||
{
|
||
tree i, max, subtype;
|
||
|
||
i = TYPE_MIN_VALUE (TYPE_DOMAIN (type));
|
||
max = TYPE_MAX_VALUE (TYPE_DOMAIN (type));
|
||
subtype = TREE_TYPE (type);
|
||
|
||
while (1)
|
||
{
|
||
instantiate_missing_elements_1 (elt, i, subtype);
|
||
if (tree_int_cst_equal (i, max))
|
||
break;
|
||
i = int_const_binop (PLUS_EXPR, i, integer_one_node, true);
|
||
}
|
||
|
||
break;
|
||
}
|
||
|
||
case COMPLEX_TYPE:
|
||
type = TREE_TYPE (type);
|
||
instantiate_missing_elements_1 (elt, integer_zero_node, type);
|
||
instantiate_missing_elements_1 (elt, integer_one_node, type);
|
||
break;
|
||
|
||
default:
|
||
gcc_unreachable ();
|
||
}
|
||
}
|
||
|
||
/* Make one pass across an element tree deciding whether to perform block
|
||
or element copies. If we decide on element copies, instantiate all
|
||
elements. Return true if there are any instantiated sub-elements. */
|
||
|
||
static bool
|
||
decide_block_copy (struct sra_elt *elt)
|
||
{
|
||
struct sra_elt *c;
|
||
bool any_inst;
|
||
|
||
/* We shouldn't be invoked on groups of sub-elements as they must
|
||
behave like their parent as far as block copy is concerned. */
|
||
gcc_assert (!elt->is_group);
|
||
|
||
/* If scalarization is disabled, respect it. */
|
||
if (elt->cannot_scalarize)
|
||
{
|
||
elt->use_block_copy = 1;
|
||
|
||
if (dump_file)
|
||
{
|
||
fputs ("Scalarization disabled for ", dump_file);
|
||
dump_sra_elt_name (dump_file, elt);
|
||
fputc ('\n', dump_file);
|
||
}
|
||
|
||
/* Disable scalarization of sub-elements */
|
||
for (c = elt->children; c; c = c->sibling)
|
||
{
|
||
c->cannot_scalarize = 1;
|
||
decide_block_copy (c);
|
||
}
|
||
|
||
/* Groups behave like their parent. */
|
||
for (c = elt->groups; c; c = c->sibling)
|
||
{
|
||
c->cannot_scalarize = 1;
|
||
c->use_block_copy = 1;
|
||
}
|
||
|
||
return false;
|
||
}
|
||
|
||
/* Don't decide if we've no uses. */
|
||
if (elt->n_uses == 0 && elt->n_copies == 0)
|
||
;
|
||
|
||
else if (!elt->is_scalar)
|
||
{
|
||
tree size_tree = TYPE_SIZE_UNIT (elt->type);
|
||
bool use_block_copy = true;
|
||
|
||
/* Tradeoffs for COMPLEX types pretty much always make it better
|
||
to go ahead and split the components. */
|
||
if (TREE_CODE (elt->type) == COMPLEX_TYPE)
|
||
use_block_copy = false;
|
||
|
||
/* Don't bother trying to figure out the rest if the structure is
|
||
so large we can't do easy arithmetic. This also forces block
|
||
copies for variable sized structures. */
|
||
else if (host_integerp (size_tree, 1))
|
||
{
|
||
unsigned HOST_WIDE_INT full_size, inst_size = 0;
|
||
unsigned int max_size, max_count, inst_count, full_count;
|
||
|
||
/* If the sra-max-structure-size parameter is 0, then the
|
||
user has not overridden the parameter and we can choose a
|
||
sensible default. */
|
||
max_size = SRA_MAX_STRUCTURE_SIZE
|
||
? SRA_MAX_STRUCTURE_SIZE
|
||
: MOVE_RATIO * UNITS_PER_WORD;
|
||
max_count = SRA_MAX_STRUCTURE_COUNT
|
||
? SRA_MAX_STRUCTURE_COUNT
|
||
: MOVE_RATIO;
|
||
|
||
full_size = tree_low_cst (size_tree, 1);
|
||
full_count = count_type_elements (elt->type, false);
|
||
inst_count = sum_instantiated_sizes (elt, &inst_size);
|
||
|
||
/* ??? What to do here. If there are two fields, and we've only
|
||
instantiated one, then instantiating the other is clearly a win.
|
||
If there are a large number of fields then the size of the copy
|
||
is much more of a factor. */
|
||
|
||
/* If the structure is small, and we've made copies, go ahead
|
||
and instantiate, hoping that the copies will go away. */
|
||
if (full_size <= max_size
|
||
&& (full_count - inst_count) <= max_count
|
||
&& elt->n_copies > elt->n_uses)
|
||
use_block_copy = false;
|
||
else if (inst_count * 100 >= full_count * SRA_FIELD_STRUCTURE_RATIO
|
||
&& inst_size * 100 >= full_size * SRA_FIELD_STRUCTURE_RATIO)
|
||
use_block_copy = false;
|
||
|
||
/* In order to avoid block copy, we have to be able to instantiate
|
||
all elements of the type. See if this is possible. */
|
||
if (!use_block_copy
|
||
&& (!can_completely_scalarize_p (elt)
|
||
|| !type_can_instantiate_all_elements (elt->type)))
|
||
use_block_copy = true;
|
||
}
|
||
|
||
elt->use_block_copy = use_block_copy;
|
||
|
||
/* Groups behave like their parent. */
|
||
for (c = elt->groups; c; c = c->sibling)
|
||
c->use_block_copy = use_block_copy;
|
||
|
||
if (dump_file)
|
||
{
|
||
fprintf (dump_file, "Using %s for ",
|
||
use_block_copy ? "block-copy" : "element-copy");
|
||
dump_sra_elt_name (dump_file, elt);
|
||
fputc ('\n', dump_file);
|
||
}
|
||
|
||
if (!use_block_copy)
|
||
{
|
||
instantiate_missing_elements (elt);
|
||
return true;
|
||
}
|
||
}
|
||
|
||
any_inst = elt->replacement != NULL;
|
||
|
||
for (c = elt->children; c ; c = c->sibling)
|
||
any_inst |= decide_block_copy (c);
|
||
|
||
return any_inst;
|
||
}
|
||
|
||
/* Entry point to phase 3. Instantiate scalar replacement variables. */
|
||
|
||
static void
|
||
decide_instantiations (void)
|
||
{
|
||
unsigned int i;
|
||
bool cleared_any;
|
||
bitmap_head done_head;
|
||
bitmap_iterator bi;
|
||
|
||
/* We cannot clear bits from a bitmap we're iterating over,
|
||
so save up all the bits to clear until the end. */
|
||
bitmap_initialize (&done_head, &bitmap_default_obstack);
|
||
cleared_any = false;
|
||
|
||
EXECUTE_IF_SET_IN_BITMAP (sra_candidates, 0, i, bi)
|
||
{
|
||
tree var = referenced_var (i);
|
||
struct sra_elt *elt = lookup_element (NULL, var, NULL, NO_INSERT);
|
||
if (elt)
|
||
{
|
||
decide_instantiation_1 (elt, 0, 0);
|
||
if (!decide_block_copy (elt))
|
||
elt = NULL;
|
||
}
|
||
if (!elt)
|
||
{
|
||
bitmap_set_bit (&done_head, i);
|
||
cleared_any = true;
|
||
}
|
||
}
|
||
|
||
if (cleared_any)
|
||
{
|
||
bitmap_and_compl_into (sra_candidates, &done_head);
|
||
bitmap_and_compl_into (needs_copy_in, &done_head);
|
||
}
|
||
bitmap_clear (&done_head);
|
||
|
||
if (!bitmap_empty_p (sra_candidates))
|
||
todoflags |= TODO_update_smt_usage;
|
||
|
||
mark_set_for_renaming (sra_candidates);
|
||
|
||
if (dump_file)
|
||
fputc ('\n', dump_file);
|
||
}
|
||
|
||
|
||
/* Phase Four: Update the function to match the replacements created. */
|
||
|
||
/* Mark all the variables in V_MAY_DEF or V_MUST_DEF operands for STMT for
|
||
renaming. This becomes necessary when we modify all of a non-scalar. */
|
||
|
||
static void
|
||
mark_all_v_defs_1 (tree stmt)
|
||
{
|
||
tree sym;
|
||
ssa_op_iter iter;
|
||
|
||
update_stmt_if_modified (stmt);
|
||
|
||
FOR_EACH_SSA_TREE_OPERAND (sym, stmt, iter, SSA_OP_ALL_VIRTUALS)
|
||
{
|
||
if (TREE_CODE (sym) == SSA_NAME)
|
||
sym = SSA_NAME_VAR (sym);
|
||
mark_sym_for_renaming (sym);
|
||
}
|
||
}
|
||
|
||
|
||
/* Mark all the variables in virtual operands in all the statements in
|
||
LIST for renaming. */
|
||
|
||
static void
|
||
mark_all_v_defs (tree list)
|
||
{
|
||
if (TREE_CODE (list) != STATEMENT_LIST)
|
||
mark_all_v_defs_1 (list);
|
||
else
|
||
{
|
||
tree_stmt_iterator i;
|
||
for (i = tsi_start (list); !tsi_end_p (i); tsi_next (&i))
|
||
mark_all_v_defs_1 (tsi_stmt (i));
|
||
}
|
||
}
|
||
|
||
/* Mark every replacement under ELT with TREE_NO_WARNING. */
|
||
|
||
static void
|
||
mark_no_warning (struct sra_elt *elt)
|
||
{
|
||
if (!elt->all_no_warning)
|
||
{
|
||
if (elt->replacement)
|
||
TREE_NO_WARNING (elt->replacement) = 1;
|
||
else
|
||
{
|
||
struct sra_elt *c;
|
||
FOR_EACH_ACTUAL_CHILD (c, elt)
|
||
mark_no_warning (c);
|
||
}
|
||
elt->all_no_warning = true;
|
||
}
|
||
}
|
||
|
||
/* Build a single level component reference to ELT rooted at BASE. */
|
||
|
||
static tree
|
||
generate_one_element_ref (struct sra_elt *elt, tree base)
|
||
{
|
||
switch (TREE_CODE (TREE_TYPE (base)))
|
||
{
|
||
case RECORD_TYPE:
|
||
{
|
||
tree field = elt->element;
|
||
|
||
/* Watch out for compatible records with differing field lists. */
|
||
if (DECL_FIELD_CONTEXT (field) != TYPE_MAIN_VARIANT (TREE_TYPE (base)))
|
||
field = find_compatible_field (TREE_TYPE (base), field);
|
||
|
||
return build3 (COMPONENT_REF, elt->type, base, field, NULL);
|
||
}
|
||
|
||
case ARRAY_TYPE:
|
||
todoflags |= TODO_update_smt_usage;
|
||
if (TREE_CODE (elt->element) == RANGE_EXPR)
|
||
return build4 (ARRAY_RANGE_REF, elt->type, base,
|
||
TREE_OPERAND (elt->element, 0), NULL, NULL);
|
||
else
|
||
return build4 (ARRAY_REF, elt->type, base, elt->element, NULL, NULL);
|
||
|
||
case COMPLEX_TYPE:
|
||
if (elt->element == integer_zero_node)
|
||
return build1 (REALPART_EXPR, elt->type, base);
|
||
else
|
||
return build1 (IMAGPART_EXPR, elt->type, base);
|
||
|
||
default:
|
||
gcc_unreachable ();
|
||
}
|
||
}
|
||
|
||
/* Build a full component reference to ELT rooted at its native variable. */
|
||
|
||
static tree
|
||
generate_element_ref (struct sra_elt *elt)
|
||
{
|
||
if (elt->parent)
|
||
return generate_one_element_ref (elt, generate_element_ref (elt->parent));
|
||
else
|
||
return elt->element;
|
||
}
|
||
|
||
static tree
|
||
sra_build_assignment (tree dst, tree src)
|
||
{
|
||
/* We need TYPE_CANONICAL to compare the types of dst and src
|
||
efficiently, but that's only introduced in GCC 4.3. */
|
||
return build2 (MODIFY_EXPR, void_type_node, dst, src);
|
||
}
|
||
|
||
/* Generate a set of assignment statements in *LIST_P to copy all
|
||
instantiated elements under ELT to or from the equivalent structure
|
||
rooted at EXPR. COPY_OUT controls the direction of the copy, with
|
||
true meaning to copy out of EXPR into ELT. */
|
||
|
||
static void
|
||
generate_copy_inout (struct sra_elt *elt, bool copy_out, tree expr,
|
||
tree *list_p)
|
||
{
|
||
struct sra_elt *c;
|
||
tree t;
|
||
|
||
if (!copy_out && TREE_CODE (expr) == SSA_NAME
|
||
&& TREE_CODE (TREE_TYPE (expr)) == COMPLEX_TYPE)
|
||
{
|
||
tree r, i;
|
||
|
||
c = lookup_element (elt, integer_zero_node, NULL, NO_INSERT);
|
||
r = c->replacement;
|
||
c = lookup_element (elt, integer_one_node, NULL, NO_INSERT);
|
||
i = c->replacement;
|
||
|
||
t = build2 (COMPLEX_EXPR, elt->type, r, i);
|
||
t = sra_build_assignment (expr, t);
|
||
SSA_NAME_DEF_STMT (expr) = t;
|
||
append_to_statement_list (t, list_p);
|
||
}
|
||
else if (elt->replacement)
|
||
{
|
||
if (copy_out)
|
||
t = sra_build_assignment (elt->replacement, expr);
|
||
else
|
||
t = sra_build_assignment (expr, elt->replacement);
|
||
append_to_statement_list (t, list_p);
|
||
}
|
||
else
|
||
{
|
||
FOR_EACH_ACTUAL_CHILD (c, elt)
|
||
{
|
||
t = generate_one_element_ref (c, unshare_expr (expr));
|
||
generate_copy_inout (c, copy_out, t, list_p);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Generate a set of assignment statements in *LIST_P to copy all instantiated
|
||
elements under SRC to their counterparts under DST. There must be a 1-1
|
||
correspondence of instantiated elements. */
|
||
|
||
static void
|
||
generate_element_copy (struct sra_elt *dst, struct sra_elt *src, tree *list_p)
|
||
{
|
||
struct sra_elt *dc, *sc;
|
||
|
||
FOR_EACH_ACTUAL_CHILD (dc, dst)
|
||
{
|
||
sc = lookup_element (src, dc->element, NULL, NO_INSERT);
|
||
gcc_assert (sc);
|
||
generate_element_copy (dc, sc, list_p);
|
||
}
|
||
|
||
if (dst->replacement)
|
||
{
|
||
tree t;
|
||
|
||
gcc_assert (src->replacement);
|
||
|
||
t = sra_build_assignment (dst->replacement, src->replacement);
|
||
append_to_statement_list (t, list_p);
|
||
}
|
||
}
|
||
|
||
/* Generate a set of assignment statements in *LIST_P to zero all instantiated
|
||
elements under ELT. In addition, do not assign to elements that have been
|
||
marked VISITED but do reset the visited flag; this allows easy coordination
|
||
with generate_element_init. */
|
||
|
||
static void
|
||
generate_element_zero (struct sra_elt *elt, tree *list_p)
|
||
{
|
||
struct sra_elt *c;
|
||
|
||
if (elt->visited)
|
||
{
|
||
elt->visited = false;
|
||
return;
|
||
}
|
||
|
||
FOR_EACH_ACTUAL_CHILD (c, elt)
|
||
generate_element_zero (c, list_p);
|
||
|
||
if (elt->replacement)
|
||
{
|
||
tree t;
|
||
|
||
gcc_assert (elt->is_scalar);
|
||
t = fold_convert (elt->type, integer_zero_node);
|
||
|
||
t = sra_build_assignment (elt->replacement, t);
|
||
append_to_statement_list (t, list_p);
|
||
}
|
||
}
|
||
|
||
/* Generate an assignment VAR = INIT, where INIT may need gimplification.
|
||
Add the result to *LIST_P. */
|
||
|
||
static void
|
||
generate_one_element_init (tree var, tree init, tree *list_p)
|
||
{
|
||
/* The replacement can be almost arbitrarily complex. Gimplify. */
|
||
tree stmt = sra_build_assignment (var, init);
|
||
gimplify_and_add (stmt, list_p);
|
||
}
|
||
|
||
/* Generate a set of assignment statements in *LIST_P to set all instantiated
|
||
elements under ELT with the contents of the initializer INIT. In addition,
|
||
mark all assigned elements VISITED; this allows easy coordination with
|
||
generate_element_zero. Return false if we found a case we couldn't
|
||
handle. */
|
||
|
||
static bool
|
||
generate_element_init_1 (struct sra_elt *elt, tree init, tree *list_p)
|
||
{
|
||
bool result = true;
|
||
enum tree_code init_code;
|
||
struct sra_elt *sub;
|
||
tree t;
|
||
unsigned HOST_WIDE_INT idx;
|
||
tree value, purpose;
|
||
|
||
/* We can be passed DECL_INITIAL of a static variable. It might have a
|
||
conversion, which we strip off here. */
|
||
STRIP_USELESS_TYPE_CONVERSION (init);
|
||
init_code = TREE_CODE (init);
|
||
|
||
if (elt->is_scalar)
|
||
{
|
||
if (elt->replacement)
|
||
{
|
||
generate_one_element_init (elt->replacement, init, list_p);
|
||
elt->visited = true;
|
||
}
|
||
return result;
|
||
}
|
||
|
||
switch (init_code)
|
||
{
|
||
case COMPLEX_CST:
|
||
case COMPLEX_EXPR:
|
||
FOR_EACH_ACTUAL_CHILD (sub, elt)
|
||
{
|
||
if (sub->element == integer_zero_node)
|
||
t = (init_code == COMPLEX_EXPR
|
||
? TREE_OPERAND (init, 0) : TREE_REALPART (init));
|
||
else
|
||
t = (init_code == COMPLEX_EXPR
|
||
? TREE_OPERAND (init, 1) : TREE_IMAGPART (init));
|
||
result &= generate_element_init_1 (sub, t, list_p);
|
||
}
|
||
break;
|
||
|
||
case CONSTRUCTOR:
|
||
FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (init), idx, purpose, value)
|
||
{
|
||
if (TREE_CODE (purpose) == RANGE_EXPR)
|
||
{
|
||
tree lower = TREE_OPERAND (purpose, 0);
|
||
tree upper = TREE_OPERAND (purpose, 1);
|
||
|
||
while (1)
|
||
{
|
||
sub = lookup_element (elt, lower, NULL, NO_INSERT);
|
||
if (sub != NULL)
|
||
result &= generate_element_init_1 (sub, value, list_p);
|
||
if (tree_int_cst_equal (lower, upper))
|
||
break;
|
||
lower = int_const_binop (PLUS_EXPR, lower,
|
||
integer_one_node, true);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
sub = lookup_element (elt, purpose, NULL, NO_INSERT);
|
||
if (sub != NULL)
|
||
result &= generate_element_init_1 (sub, value, list_p);
|
||
}
|
||
}
|
||
break;
|
||
|
||
default:
|
||
elt->visited = true;
|
||
result = false;
|
||
}
|
||
|
||
return result;
|
||
}
|
||
|
||
/* A wrapper function for generate_element_init_1 that handles cleanup after
|
||
gimplification. */
|
||
|
||
static bool
|
||
generate_element_init (struct sra_elt *elt, tree init, tree *list_p)
|
||
{
|
||
bool ret;
|
||
|
||
push_gimplify_context ();
|
||
ret = generate_element_init_1 (elt, init, list_p);
|
||
pop_gimplify_context (NULL);
|
||
|
||
/* The replacement can expose previously unreferenced variables. */
|
||
if (ret && *list_p)
|
||
{
|
||
tree_stmt_iterator i;
|
||
|
||
for (i = tsi_start (*list_p); !tsi_end_p (i); tsi_next (&i))
|
||
find_new_referenced_vars (tsi_stmt_ptr (i));
|
||
}
|
||
|
||
return ret;
|
||
}
|
||
|
||
/* Insert STMT on all the outgoing edges out of BB. Note that if BB
|
||
has more than one edge, STMT will be replicated for each edge. Also,
|
||
abnormal edges will be ignored. */
|
||
|
||
void
|
||
insert_edge_copies (tree stmt, basic_block bb)
|
||
{
|
||
edge e;
|
||
edge_iterator ei;
|
||
bool first_copy;
|
||
|
||
first_copy = true;
|
||
FOR_EACH_EDGE (e, ei, bb->succs)
|
||
{
|
||
/* We don't need to insert copies on abnormal edges. The
|
||
value of the scalar replacement is not guaranteed to
|
||
be valid through an abnormal edge. */
|
||
if (!(e->flags & EDGE_ABNORMAL))
|
||
{
|
||
if (first_copy)
|
||
{
|
||
bsi_insert_on_edge (e, stmt);
|
||
first_copy = false;
|
||
}
|
||
else
|
||
bsi_insert_on_edge (e, unsave_expr_now (stmt));
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Helper function to insert LIST before BSI, and set up line number info. */
|
||
|
||
void
|
||
sra_insert_before (block_stmt_iterator *bsi, tree list)
|
||
{
|
||
tree stmt = bsi_stmt (*bsi);
|
||
|
||
if (EXPR_HAS_LOCATION (stmt))
|
||
annotate_all_with_locus (&list, EXPR_LOCATION (stmt));
|
||
bsi_insert_before (bsi, list, BSI_SAME_STMT);
|
||
}
|
||
|
||
/* Similarly, but insert after BSI. Handles insertion onto edges as well. */
|
||
|
||
void
|
||
sra_insert_after (block_stmt_iterator *bsi, tree list)
|
||
{
|
||
tree stmt = bsi_stmt (*bsi);
|
||
|
||
if (EXPR_HAS_LOCATION (stmt))
|
||
annotate_all_with_locus (&list, EXPR_LOCATION (stmt));
|
||
|
||
if (stmt_ends_bb_p (stmt))
|
||
insert_edge_copies (list, bsi->bb);
|
||
else
|
||
bsi_insert_after (bsi, list, BSI_SAME_STMT);
|
||
}
|
||
|
||
/* Similarly, but replace the statement at BSI. */
|
||
|
||
static void
|
||
sra_replace (block_stmt_iterator *bsi, tree list)
|
||
{
|
||
sra_insert_before (bsi, list);
|
||
bsi_remove (bsi, false);
|
||
if (bsi_end_p (*bsi))
|
||
*bsi = bsi_last (bsi->bb);
|
||
else
|
||
bsi_prev (bsi);
|
||
}
|
||
|
||
/* Scalarize a USE. To recap, this is either a simple reference to ELT,
|
||
if elt is scalar, or some occurrence of ELT that requires a complete
|
||
aggregate. IS_OUTPUT is true if ELT is being modified. */
|
||
|
||
static void
|
||
scalarize_use (struct sra_elt *elt, tree *expr_p, block_stmt_iterator *bsi,
|
||
bool is_output, bool use_all)
|
||
{
|
||
tree list = NULL, stmt = bsi_stmt (*bsi);
|
||
|
||
if (elt->replacement)
|
||
{
|
||
/* If we have a replacement, then updating the reference is as
|
||
simple as modifying the existing statement in place. */
|
||
if (is_output)
|
||
mark_all_v_defs (stmt);
|
||
*expr_p = elt->replacement;
|
||
update_stmt (stmt);
|
||
}
|
||
else
|
||
{
|
||
/* Otherwise we need some copies. If ELT is being read, then we want
|
||
to store all (modified) sub-elements back into the structure before
|
||
the reference takes place. If ELT is being written, then we want to
|
||
load the changed values back into our shadow variables. */
|
||
/* ??? We don't check modified for reads, we just always write all of
|
||
the values. We should be able to record the SSA number of the VOP
|
||
for which the values were last read. If that number matches the
|
||
SSA number of the VOP in the current statement, then we needn't
|
||
emit an assignment. This would also eliminate double writes when
|
||
a structure is passed as more than one argument to a function call.
|
||
This optimization would be most effective if sra_walk_function
|
||
processed the blocks in dominator order. */
|
||
|
||
generate_copy_inout (elt, is_output, generate_element_ref (elt), &list);
|
||
if (list == NULL)
|
||
return;
|
||
mark_all_v_defs (list);
|
||
if (is_output)
|
||
sra_insert_after (bsi, list);
|
||
else
|
||
{
|
||
sra_insert_before (bsi, list);
|
||
if (use_all)
|
||
mark_no_warning (elt);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Scalarize a COPY. To recap, this is an assignment statement between
|
||
two scalarizable references, LHS_ELT and RHS_ELT. */
|
||
|
||
static void
|
||
scalarize_copy (struct sra_elt *lhs_elt, struct sra_elt *rhs_elt,
|
||
block_stmt_iterator *bsi)
|
||
{
|
||
tree list, stmt;
|
||
|
||
if (lhs_elt->replacement && rhs_elt->replacement)
|
||
{
|
||
/* If we have two scalar operands, modify the existing statement. */
|
||
stmt = bsi_stmt (*bsi);
|
||
|
||
/* See the commentary in sra_walk_function concerning
|
||
RETURN_EXPR, and why we should never see one here. */
|
||
gcc_assert (TREE_CODE (stmt) == MODIFY_EXPR);
|
||
|
||
TREE_OPERAND (stmt, 0) = lhs_elt->replacement;
|
||
TREE_OPERAND (stmt, 1) = rhs_elt->replacement;
|
||
update_stmt (stmt);
|
||
}
|
||
else if (lhs_elt->use_block_copy || rhs_elt->use_block_copy)
|
||
{
|
||
/* If either side requires a block copy, then sync the RHS back
|
||
to the original structure, leave the original assignment
|
||
statement (which will perform the block copy), then load the
|
||
LHS values out of its now-updated original structure. */
|
||
/* ??? Could perform a modified pair-wise element copy. That
|
||
would at least allow those elements that are instantiated in
|
||
both structures to be optimized well. */
|
||
|
||
list = NULL;
|
||
generate_copy_inout (rhs_elt, false,
|
||
generate_element_ref (rhs_elt), &list);
|
||
if (list)
|
||
{
|
||
mark_all_v_defs (list);
|
||
sra_insert_before (bsi, list);
|
||
}
|
||
|
||
list = NULL;
|
||
generate_copy_inout (lhs_elt, true,
|
||
generate_element_ref (lhs_elt), &list);
|
||
if (list)
|
||
{
|
||
mark_all_v_defs (list);
|
||
sra_insert_after (bsi, list);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* Otherwise both sides must be fully instantiated. In which
|
||
case perform pair-wise element assignments and replace the
|
||
original block copy statement. */
|
||
|
||
stmt = bsi_stmt (*bsi);
|
||
mark_all_v_defs (stmt);
|
||
|
||
list = NULL;
|
||
generate_element_copy (lhs_elt, rhs_elt, &list);
|
||
gcc_assert (list);
|
||
mark_all_v_defs (list);
|
||
sra_replace (bsi, list);
|
||
}
|
||
}
|
||
|
||
/* Scalarize an INIT. To recap, this is an assignment to a scalarizable
|
||
reference from some form of constructor: CONSTRUCTOR, COMPLEX_CST or
|
||
COMPLEX_EXPR. If RHS is NULL, it should be treated as an empty
|
||
CONSTRUCTOR. */
|
||
|
||
static void
|
||
scalarize_init (struct sra_elt *lhs_elt, tree rhs, block_stmt_iterator *bsi)
|
||
{
|
||
bool result = true;
|
||
tree list = NULL;
|
||
|
||
/* Generate initialization statements for all members extant in the RHS. */
|
||
if (rhs)
|
||
{
|
||
/* Unshare the expression just in case this is from a decl's initial. */
|
||
rhs = unshare_expr (rhs);
|
||
result = generate_element_init (lhs_elt, rhs, &list);
|
||
}
|
||
|
||
/* CONSTRUCTOR is defined such that any member not mentioned is assigned
|
||
a zero value. Initialize the rest of the instantiated elements. */
|
||
generate_element_zero (lhs_elt, &list);
|
||
|
||
if (!result)
|
||
{
|
||
/* If we failed to convert the entire initializer, then we must
|
||
leave the structure assignment in place and must load values
|
||
from the structure into the slots for which we did not find
|
||
constants. The easiest way to do this is to generate a complete
|
||
copy-out, and then follow that with the constant assignments
|
||
that we were able to build. DCE will clean things up. */
|
||
tree list0 = NULL;
|
||
generate_copy_inout (lhs_elt, true, generate_element_ref (lhs_elt),
|
||
&list0);
|
||
append_to_statement_list (list, &list0);
|
||
list = list0;
|
||
}
|
||
|
||
if (lhs_elt->use_block_copy || !result)
|
||
{
|
||
/* Since LHS is not fully instantiated, we must leave the structure
|
||
assignment in place. Treating this case differently from a USE
|
||
exposes constants to later optimizations. */
|
||
if (list)
|
||
{
|
||
mark_all_v_defs (list);
|
||
sra_insert_after (bsi, list);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* The LHS is fully instantiated. The list of initializations
|
||
replaces the original structure assignment. */
|
||
gcc_assert (list);
|
||
mark_all_v_defs (bsi_stmt (*bsi));
|
||
mark_all_v_defs (list);
|
||
sra_replace (bsi, list);
|
||
}
|
||
}
|
||
|
||
/* A subroutine of scalarize_ldst called via walk_tree. Set TREE_NO_TRAP
|
||
on all INDIRECT_REFs. */
|
||
|
||
static tree
|
||
mark_notrap (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
|
||
{
|
||
tree t = *tp;
|
||
|
||
if (TREE_CODE (t) == INDIRECT_REF)
|
||
{
|
||
TREE_THIS_NOTRAP (t) = 1;
|
||
*walk_subtrees = 0;
|
||
}
|
||
else if (IS_TYPE_OR_DECL_P (t))
|
||
*walk_subtrees = 0;
|
||
|
||
return NULL;
|
||
}
|
||
|
||
/* Scalarize a LDST. To recap, this is an assignment between one scalarizable
|
||
reference ELT and one non-scalarizable reference OTHER. IS_OUTPUT is true
|
||
if ELT is on the left-hand side. */
|
||
|
||
static void
|
||
scalarize_ldst (struct sra_elt *elt, tree other,
|
||
block_stmt_iterator *bsi, bool is_output)
|
||
{
|
||
/* Shouldn't have gotten called for a scalar. */
|
||
gcc_assert (!elt->replacement);
|
||
|
||
if (elt->use_block_copy)
|
||
{
|
||
/* Since ELT is not fully instantiated, we have to leave the
|
||
block copy in place. Treat this as a USE. */
|
||
scalarize_use (elt, NULL, bsi, is_output, false);
|
||
}
|
||
else
|
||
{
|
||
/* The interesting case is when ELT is fully instantiated. In this
|
||
case we can have each element stored/loaded directly to/from the
|
||
corresponding slot in OTHER. This avoids a block copy. */
|
||
|
||
tree list = NULL, stmt = bsi_stmt (*bsi);
|
||
|
||
mark_all_v_defs (stmt);
|
||
generate_copy_inout (elt, is_output, other, &list);
|
||
mark_all_v_defs (list);
|
||
gcc_assert (list);
|
||
|
||
/* Preserve EH semantics. */
|
||
if (stmt_ends_bb_p (stmt))
|
||
{
|
||
tree_stmt_iterator tsi;
|
||
tree first;
|
||
|
||
/* Extract the first statement from LIST. */
|
||
tsi = tsi_start (list);
|
||
first = tsi_stmt (tsi);
|
||
tsi_delink (&tsi);
|
||
|
||
/* Replace the old statement with this new representative. */
|
||
bsi_replace (bsi, first, true);
|
||
|
||
if (!tsi_end_p (tsi))
|
||
{
|
||
/* If any reference would trap, then they all would. And more
|
||
to the point, the first would. Therefore none of the rest
|
||
will trap since the first didn't. Indicate this by
|
||
iterating over the remaining statements and set
|
||
TREE_THIS_NOTRAP in all INDIRECT_REFs. */
|
||
do
|
||
{
|
||
walk_tree (tsi_stmt_ptr (tsi), mark_notrap, NULL, NULL);
|
||
tsi_next (&tsi);
|
||
}
|
||
while (!tsi_end_p (tsi));
|
||
|
||
insert_edge_copies (list, bsi->bb);
|
||
}
|
||
}
|
||
else
|
||
sra_replace (bsi, list);
|
||
}
|
||
}
|
||
|
||
/* Generate initializations for all scalarizable parameters. */
|
||
|
||
static void
|
||
scalarize_parms (void)
|
||
{
|
||
tree list = NULL;
|
||
unsigned i;
|
||
bitmap_iterator bi;
|
||
|
||
EXECUTE_IF_SET_IN_BITMAP (needs_copy_in, 0, i, bi)
|
||
{
|
||
tree var = referenced_var (i);
|
||
struct sra_elt *elt = lookup_element (NULL, var, NULL, NO_INSERT);
|
||
generate_copy_inout (elt, true, var, &list);
|
||
}
|
||
|
||
if (list)
|
||
{
|
||
insert_edge_copies (list, ENTRY_BLOCK_PTR);
|
||
mark_all_v_defs (list);
|
||
}
|
||
}
|
||
|
||
/* Entry point to phase 4. Update the function to match replacements. */
|
||
|
||
static void
|
||
scalarize_function (void)
|
||
{
|
||
static const struct sra_walk_fns fns = {
|
||
scalarize_use, scalarize_copy, scalarize_init, scalarize_ldst, false
|
||
};
|
||
|
||
sra_walk_function (&fns);
|
||
scalarize_parms ();
|
||
bsi_commit_edge_inserts ();
|
||
}
|
||
|
||
|
||
/* Debug helper function. Print ELT in a nice human-readable format. */
|
||
|
||
static void
|
||
dump_sra_elt_name (FILE *f, struct sra_elt *elt)
|
||
{
|
||
if (elt->parent && TREE_CODE (elt->parent->type) == COMPLEX_TYPE)
|
||
{
|
||
fputs (elt->element == integer_zero_node ? "__real__ " : "__imag__ ", f);
|
||
dump_sra_elt_name (f, elt->parent);
|
||
}
|
||
else
|
||
{
|
||
if (elt->parent)
|
||
dump_sra_elt_name (f, elt->parent);
|
||
if (DECL_P (elt->element))
|
||
{
|
||
if (TREE_CODE (elt->element) == FIELD_DECL)
|
||
fputc ('.', f);
|
||
print_generic_expr (f, elt->element, dump_flags);
|
||
}
|
||
else if (TREE_CODE (elt->element) == RANGE_EXPR)
|
||
fprintf (f, "["HOST_WIDE_INT_PRINT_DEC".."HOST_WIDE_INT_PRINT_DEC"]",
|
||
TREE_INT_CST_LOW (TREE_OPERAND (elt->element, 0)),
|
||
TREE_INT_CST_LOW (TREE_OPERAND (elt->element, 1)));
|
||
else
|
||
fprintf (f, "[" HOST_WIDE_INT_PRINT_DEC "]",
|
||
TREE_INT_CST_LOW (elt->element));
|
||
}
|
||
}
|
||
|
||
/* Likewise, but callable from the debugger. */
|
||
|
||
void
|
||
debug_sra_elt_name (struct sra_elt *elt)
|
||
{
|
||
dump_sra_elt_name (stderr, elt);
|
||
fputc ('\n', stderr);
|
||
}
|
||
|
||
void
|
||
sra_init_cache (void)
|
||
{
|
||
if (sra_type_decomp_cache)
|
||
return;
|
||
|
||
sra_type_decomp_cache = BITMAP_ALLOC (NULL);
|
||
sra_type_inst_cache = BITMAP_ALLOC (NULL);
|
||
}
|
||
|
||
/* Main entry point. */
|
||
|
||
static unsigned int
|
||
tree_sra (void)
|
||
{
|
||
/* Initialize local variables. */
|
||
todoflags = 0;
|
||
gcc_obstack_init (&sra_obstack);
|
||
sra_candidates = BITMAP_ALLOC (NULL);
|
||
needs_copy_in = BITMAP_ALLOC (NULL);
|
||
sra_init_cache ();
|
||
sra_map = htab_create (101, sra_elt_hash, sra_elt_eq, NULL);
|
||
|
||
/* Scan. If we find anything, instantiate and scalarize. */
|
||
if (find_candidates_for_sra ())
|
||
{
|
||
scan_function ();
|
||
decide_instantiations ();
|
||
scalarize_function ();
|
||
}
|
||
|
||
/* Free allocated memory. */
|
||
htab_delete (sra_map);
|
||
sra_map = NULL;
|
||
BITMAP_FREE (sra_candidates);
|
||
BITMAP_FREE (needs_copy_in);
|
||
BITMAP_FREE (sra_type_decomp_cache);
|
||
BITMAP_FREE (sra_type_inst_cache);
|
||
obstack_free (&sra_obstack, NULL);
|
||
return todoflags;
|
||
}
|
||
|
||
static bool
|
||
gate_sra (void)
|
||
{
|
||
return flag_tree_sra != 0;
|
||
}
|
||
|
||
struct tree_opt_pass pass_sra =
|
||
{
|
||
"sra", /* name */
|
||
gate_sra, /* gate */
|
||
tree_sra, /* execute */
|
||
NULL, /* sub */
|
||
NULL, /* next */
|
||
0, /* static_pass_number */
|
||
TV_TREE_SRA, /* tv_id */
|
||
PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
|
||
0, /* properties_provided */
|
||
PROP_smt_usage, /* properties_destroyed */
|
||
0, /* todo_flags_start */
|
||
TODO_dump_func /* todo_flags_finish */
|
||
| TODO_update_ssa
|
||
| TODO_ggc_collect | TODO_verify_ssa,
|
||
0 /* letter */
|
||
};
|