Hi!
compute_all_dependences in 4.7+ can fail, and cond_if_else_store_replacement
isn't prepared to handle the chrec_dont_know DDR added there in case of
failure (with NULL DDR_A/DDR_B).
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
ok for trunk/4.7?
BTW, tree-ssa-loop-prefetch.c seems to have the same problem, but no idea
how that should be handled in there...
2012-04-30 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/53163
* tree-ssa-phiopt.c (cond_if_else_store_replacement): Don't ignore
return value from compute_all_dependences.
* gcc.c-torture/compile/pr53163.c: New test.
--- gcc/tree-ssa-phiopt.c.jj 2012-04-30 08:06:18.000000000 +0200
+++ gcc/tree-ssa-phiopt.c 2012-04-30 08:59:16.726488101 +0200
@@ -1624,8 +1624,17 @@ cond_if_else_store_replacement (basic_bl
/* Compute and check data dependencies in both basic blocks. */
then_ddrs = VEC_alloc (ddr_p, heap, 1);
else_ddrs = VEC_alloc (ddr_p, heap, 1);
- compute_all_dependences (then_datarefs, &then_ddrs, NULL, false);
- compute_all_dependences (else_datarefs, &else_ddrs, NULL, false);
+ if (!compute_all_dependences (then_datarefs, &then_ddrs, NULL, false)
+ || !compute_all_dependences (else_datarefs, &else_ddrs, NULL, false))
+ {
+ free_dependence_relations (then_ddrs);
+ free_dependence_relations (else_ddrs);
+ free_data_refs (then_datarefs);
+ free_data_refs (else_datarefs);
+ VEC_free (gimple, heap, then_stores);
+ VEC_free (gimple, heap, else_stores);
+ return false;
+ }
blocks[0] = then_bb;
blocks[1] = else_bb;
blocks[2] = join_bb;
--- gcc/testsuite/gcc.c-torture/compile/pr53163.c.jj 2012-04-30
09:21:40.950512562 +0200
+++ gcc/testsuite/gcc.c-torture/compile/pr53163.c 2012-04-30
09:21:20.000000000 +0200
@@ -0,0 +1,34 @@
+/* PR tree-optimization/53163 */
+
+struct S { int s; } b, f;
+int a, c;
+
+void
+foo (void)
+{
+ int d, e;
+ for (d = 4; d < 19; ++d)
+ for (e = 2; e >= 0; e--)
+ {
+ a = 0;
+ a = 1;
+ }
+}
+
+void
+bar (void)
+{
+ int g, h, i;
+ for (i = 1; i >= 0; i--)
+ {
+ b = f;
+ for (g = 0; g <= 1; g++)
+ {
+ if (c)
+ break;
+ for (h = 0; h <= 1; h++)
+ foo ();
+ foo ();
+ }
+ }
+}
Jakub
