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| author | Alexandre Oliva <aoliva@redhat.com> | 2015-11-03 00:30:07 +0000 |
|---|---|---|
| committer | Alexandre Oliva <aoliva@gcc.gnu.org> | 2015-11-03 00:30:07 +0000 |
| commit | 828ca3d835ac006cbcb2e5b480c6429cc8a75bdd (patch) | |
| tree | 97886b9d02ac0ccd0177983b325624a1c00e5f03 /gcc/tree-ssa-ifcombine.c | |
| parent | dac7e9b81974a69fc437d5115ebb46de11da14de (diff) | |
[PR68083] don't introduce undefined behavior in ifcombine
The ifcombine pass may move a conditional access to an uninitialized
value before the condition that ensures it is always well-defined,
thus introducing undefined behavior. Stop it from doing so.
for gcc/ChangeLog
PR tree-optimization/68083
* tree-ssa-ifcombine.c: Include tree-ssa.h.
(bb_no_side_effects_p): Test for undefined uses too.
* tree-ssa.c (gimple_uses_undefined_value_p): New.
* tree-ssa.h (gimple_uses_undefined_value_p): Declare.
for gcc/testsuite/ChangeLog
PR tree-optimization/68083
* gcc.dg/torture/pr68083.c: New. From Zhendong Su.
From-SVN: r229690
Diffstat (limited to 'gcc/tree-ssa-ifcombine.c')
| -rw-r--r-- | gcc/tree-ssa-ifcombine.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/gcc/tree-ssa-ifcombine.c b/gcc/tree-ssa-ifcombine.c index b812d9a8fc5..c18de7e607e 100644 --- a/gcc/tree-ssa-ifcombine.c +++ b/gcc/tree-ssa-ifcombine.c @@ -38,6 +38,7 @@ along with GCC; see the file COPYING3. If not see #include "gimple-iterator.h" #include "gimplify-me.h" #include "tree-cfg.h" +#include "tree-ssa.h" #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT #define LOGICAL_OP_NON_SHORT_CIRCUIT \ @@ -122,6 +123,7 @@ bb_no_side_effects_p (basic_block bb) continue; if (gimple_has_side_effects (stmt) + || gimple_uses_undefined_value_p (stmt) || gimple_could_trap_p (stmt) || gimple_vuse (stmt)) return false; |