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re PR tree-optimization/51315 (unaligned memory accesses generated with -ftree-sra)

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PR tree-optimization/51315
	* tree-sra.c (tree_non_aligned_mem_for_access_p): New predicate.
	(build_accesses_from_assign): Use it instead of tree_non_aligned_mem_p.

From-SVN: r182932
This commit is contained in:
Eric Botcazou 2012-01-05 22:21:29 +00:00 committed by Eric Botcazou
parent 2d130b315d
commit c3e686a350
4 changed files with 56 additions and 4 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2012-01-05 Eric Botcazou <ebotcazou@adacore.com>
PR tree-optimization/51315
* tree-sra.c (tree_non_aligned_mem_for_access_p): New predicate.
(build_accesses_from_assign): Use it instead of tree_non_aligned_mem_p.
2012-01-05 Uros Bizjak <ubizjak@gmail.com>
PR target/51681

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2012-01-05 Eric Botcazou <ebotcazou@adacore.com>
* gcc.c-torture/execute/20120104-1.c: New test.
2012-01-05 Paul Thomas <pault@gcc.gnu.org>
PR fortran/PR48946

24
gcc/testsuite/gcc.c-torture/execute/20120105-1.c Normal file
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@ -0,0 +1,24 @@
struct __attribute__((packed)) S
{
int a, b, c;
};
static int __attribute__ ((noinline,noclone))
extract(const char *p)
{
struct S s;
__builtin_memcpy (&s, p, sizeof(struct S));
return s.a;
}
volatile int i;
int main (void)
{
char p[sizeof(struct S) + 1];
__builtin_memset (p, 0, sizeof(struct S) + 1);
i = extract (p + 1);
return 0;
}

25
gcc/tree-sra.c
View File

@ -1095,6 +1095,25 @@ tree_non_aligned_mem_p (tree exp, unsigned int align)
return false;
}
/* Return true if EXP is a memory reference less aligned than what the access
ACC would require. This is invoked only on strict-alignment targets. */
static bool
tree_non_aligned_mem_for_access_p (tree exp, struct access *acc)
{
unsigned int acc_align;
/* The alignment of the access is that of its expression. However, it may
have been artificially increased, e.g. by a local alignment promotion,
so we cap it to the alignment of the type of the base, on the grounds
that valid sub-accesses cannot be more aligned than that. */
acc_align = get_object_alignment (acc->expr);
if (acc->base && acc_align > TYPE_ALIGN (TREE_TYPE (acc->base)))
acc_align = TYPE_ALIGN (TREE_TYPE (acc->base));
return tree_non_aligned_mem_p (exp, acc_align);
}
/* Scan expressions occuring in STMT, create access structures for all accesses
to candidates for scalarization and remove those candidates which occur in
statements or expressions that prevent them from being split apart. Return
@ -1123,8 +1142,7 @@ build_accesses_from_assign (gimple stmt)
if (lacc)
{
lacc->grp_assignment_write = 1;
if (STRICT_ALIGNMENT
&& tree_non_aligned_mem_p (rhs, get_object_alignment (lhs)))
if (STRICT_ALIGNMENT && tree_non_aligned_mem_for_access_p (rhs, lacc))
lacc->grp_unscalarizable_region = 1;
}
@ -1134,8 +1152,7 @@ build_accesses_from_assign (gimple stmt)
if (should_scalarize_away_bitmap && !gimple_has_volatile_ops (stmt)
&& !is_gimple_reg_type (racc->type))
bitmap_set_bit (should_scalarize_away_bitmap, DECL_UID (racc->base));
if (STRICT_ALIGNMENT
&& tree_non_aligned_mem_p (lhs, get_object_alignment (rhs)))
if (STRICT_ALIGNMENT && tree_non_aligned_mem_for_access_p (lhs, racc))
racc->grp_unscalarizable_region = 1;
}