diff --git a/gcc/gimple-range-cache.cc b/gcc/gimple-range-cache.cc index cc56fd4dcb0..6a098d8ec28 100644 --- a/gcc/gimple-range-cache.cc +++ b/gcc/gimple-range-cache.cc @@ -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); } diff --git a/gcc/testsuite/gcc.dg/pr109238.c b/gcc/testsuite/gcc.dg/pr109238.c new file mode 100644 index 00000000000..0cad8237208 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr109238.c @@ -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'" } */ +}