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Ranger cache dominator queries should ignore backedges.

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When querying dominators for cache values, ignore back edges in
read-only mode.

	PR tree-optimization/109238
	gcc/
	* gimple-range-cache.cc (ranger_cache::resolve_dom): Ignore
	predecessors which this block dominates.

	gcc/testsuite/
	* gcc.dg/pr109238.c: New.
This commit is contained in:
Andrew MacLeod 2023-03-23 10:28:34 -04:00
parent ed626f18b1
commit 0409aa5a2d
2 changed files with 21 additions and 0 deletions
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5
gcc/gimple-range-cache.cc
View file

@ -1404,6 +1404,11 @@ ranger_cache::resolve_dom (vrange &r, tree name, basic_block bb)
Value_Range er (TREE_TYPE (name));
FOR_EACH_EDGE (e, ei, bb->preds)
{
// If the predecessor is dominated by this block, then there is a back
// edge, and won't provide anything useful. We'll actually end up with
// VARYING as we will not resolve this node.
if (dominated_by_p (CDI_DOMINATORS, e->src, bb))
continue;
edge_range (er, e, name, RFD_READ_ONLY);
r.union_ (er);
}

16
gcc/testsuite/gcc.dg/pr109238.c Normal file
View file

@ -0,0 +1,16 @@
/* PR tree-optimization/109238 */
/* { dg-do compile } */
/* { dg-options "-O2 -Wall" } */
void foo (void *) __attribute__((noreturn));
void bar (void *);
void
baz (void *p)
{
void *c = __builtin_realloc (p, 16);
if (c)
foo (c);
for (;;)
bar (__builtin_realloc (p, 8)); /* { dg-bogus "pointer 'p' may be used after '__builtin_realloc'" } */
}