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bswap: Handle bswapping of pointers [PR96573] 

In GCC8/9 we used to optimize this into a bswap, but we no longer do.
Handling byteswapping of pointers is easy, all we need is to allow them,
for the __builtin_bswap* we already use TYPE_PRECISION to determine
the precision and we cast the operand and result to the correct type
if they aren't uselessly convertible to what the builtin expects.

2021-04-01  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/96573
	* gimple-ssa-store-merging.c (init_symbolic_number): Handle
	also pointer types.

	* gcc.dg/pr96573.c: New test.
This commit is contained in:
Jakub Jelinek 2021-04-01 10:51:03 +02:00
parent b75c4e1384
commit 5b9a65ecbe
2 changed files with 21 additions and 1 deletions
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2
gcc/gimple-ssa-store-merging.c
View File

@ -333,7 +333,7 @@ init_symbolic_number (struct symbolic_number *n, tree src)
{
int size;
if (! INTEGRAL_TYPE_P (TREE_TYPE (src)))
if (!INTEGRAL_TYPE_P (TREE_TYPE (src)) && !POINTER_TYPE_P (TREE_TYPE (src)))
return false;
n->base_addr = n->offset = n->alias_set = n->vuse = NULL_TREE;

20
gcc/testsuite/gcc.dg/pr96573.c Normal file
View File

@ -0,0 +1,20 @@
/* PR tree-optimization/96573 */
/* { dg-do compile { target { lp64 || ilp32 } } } */
/* { dg-require-effective-target bswap } */
/* { dg-options "-O3 -fdump-tree-optimized" } */
/* { dg-final { scan-tree-dump "__builtin_bswap" "optimized" } } */
typedef __SIZE_TYPE__ size_t;
void *
foo (void * const p)
{
const size_t m = sizeof (p) - 1;
const unsigned char * const o = (unsigned char*) &p;
void *n;
unsigned char * const q = (unsigned char *) &n;
unsigned char i;
for (i = 0; i <= m; ++i)
q[m - i] = o[i];
return n;
}