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tree-optimization/110496 - TYPE_PRECISION issue with store-merging

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When store-merging looks for bswap opportunities we also handle
BIT_FIELD_REFs where we verify the refed object is of scalar
type but we don't check for the result type we eventually use.
That's done later but after we eventually query TYPE_PRECISION.
The following re-orders this.

	PR tree-optimization/110496
	* gimple-ssa-store-merging.cc (find_bswap_or_nop_1): Re-order
	verifying and TYPE_PRECISION query for the BIT_FIELD_REF case.

	* gcc.dg/pr110496.c: New testcase.
This commit is contained in:
Richard Biener 2023-06-30 12:03:26 +02:00
parent 50cb9df720
commit 4f8e31e01b
2 changed files with 30 additions and 1 deletions
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5
gcc/gimple-ssa-store-merging.cc
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@ -650,10 +650,13 @@ find_bswap_or_nop_1 (gimple *stmt, struct symbolic_number *n, int limit)
/* Convert. */
n->type = TREE_TYPE (rhs1);
if (!verify_symbolic_number_p (n, stmt))
return NULL;
if (!n->base_addr)
n->range = TYPE_PRECISION (n->type) / BITS_PER_UNIT;
return verify_symbolic_number_p (n, stmt) ? stmt : NULL;
return stmt;
}
return NULL;

26
gcc/testsuite/gcc.dg/pr110496.c Normal file
View file

@ -0,0 +1,26 @@
/* { dg-do compile } */
/* { dg-options "-O2" } */
long contents, f_num;
int decide();
int f_MV0__x;
void f() {
unsigned char *rptr;
unsigned char valbuf[6];
rptr = (unsigned char *)contents;
if (decide())
do {
__builtin_memcpy(valbuf, &f_MV0__x, sizeof(int));
(&valbuf[0])[4] = (&valbuf[0])[5] = 0;
} while (0);
else {
int MV0__x = f_num;
__builtin_memcpy(valbuf, &MV0__x, sizeof(int));
(&valbuf[0])[4] = (&valbuf[0])[5] = 0;
}
rptr[1] = valbuf[4];
rptr[2] = valbuf[5];
rptr[4] = valbuf[1];
rptr[5] = valbuf[2];
__builtin_memset(valbuf, 0, 8);
}