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middle-end/94206 fix memset folding to avoid types with padding

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This makes sure that the store a memset is folded to uses a type
covering all bits.

2020-03-18   Richard Biener  <rguenther@suse.de>

	PR middle-end/94206
	* gimple-fold.c (gimple_fold_builtin_memset): Avoid using
	partial int modes or not mode-precision integer types for
	the store.

	* gcc.dg/torture/pr94206.c: New testcase.
This commit is contained in:
Richard Biener 2020-03-18 13:11:30 +01:00
parent d5029d4594
commit 1ba9acb11e
4 changed files with 35 additions and 0 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2020-03-18 Richard Biener <rguenther@suse.de>
PR middle-end/94206
* gimple-fold.c (gimple_fold_builtin_memset): Avoid using
partial int modes or not mode-precision integer types for
the store.
2020-03-18 Jakub Jelinek <jakub@redhat.com>
* asan.c (get_mem_refs_of_builtin_call): Fix up duplicated word issue

6
gcc/gimple-fold.c
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@ -1235,12 +1235,18 @@ gimple_fold_builtin_memset (gimple_stmt_iterator *gsi, tree c, tree len)
length = tree_to_uhwi (len);
if (GET_MODE_SIZE (SCALAR_INT_TYPE_MODE (etype)) != length
|| (GET_MODE_PRECISION (SCALAR_INT_TYPE_MODE (etype))
!= GET_MODE_BITSIZE (SCALAR_INT_TYPE_MODE (etype)))
|| get_pointer_alignment (dest) / BITS_PER_UNIT < length)
return NULL_TREE;
if (length > HOST_BITS_PER_WIDE_INT / BITS_PER_UNIT)
return NULL_TREE;
if (!type_has_mode_precision_p (etype))
etype = lang_hooks.types.type_for_mode (SCALAR_INT_TYPE_MODE (etype),
TYPE_UNSIGNED (etype));
if (integer_zerop (c))
cval = 0;
else

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2020-03-18 Richard Biener <rguenther@suse.de>
PR middle-end/94206
* gcc.dg/torture/pr94206.c: New testcase.
2020-03-18 Duan bo <duanbo3@huawei.com>
PR target/94201

17
gcc/testsuite/gcc.dg/torture/pr94206.c Normal file
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@ -0,0 +1,17 @@
/* { dg-do run { target lp64 } } */
struct {
unsigned long x:33;
} s;
typedef __typeof__(s.x + 0) uint33;
int main()
{
uint33 x;
__builtin_memset(&x, -1, sizeof x);
unsigned long u;
__builtin_memcpy(&u, &x, sizeof u);
if (u != -1ul)
__builtin_abort ();
return 0;
}