Fix another case of live_in at irreducible loop entry.
GVN was implicitly extending the liveness of an instruction across
an irreducible loop.
Fix this problem by clearing the value set at loop entries that contain
an irreducible loop.
bug:28252896
(cherry picked from commit 77ce6430af2709432b22344ed656edd8ec80581b)
Change-Id: Ie0121e83b2dfe47bcd184b90a69c0194d13fce54
diff --git a/compiler/optimizing/licm.cc b/compiler/optimizing/licm.cc
index 5a0b89c..7543cd6 100644
--- a/compiler/optimizing/licm.cc
+++ b/compiler/optimizing/licm.cc
@@ -101,16 +101,6 @@
SideEffects loop_effects = side_effects_.GetLoopEffects(block);
HBasicBlock* pre_header = loop_info->GetPreHeader();
- bool contains_irreducible_loop = false;
- if (graph_->HasIrreducibleLoops()) {
- for (HBlocksInLoopIterator it_loop(*loop_info); !it_loop.Done(); it_loop.Advance()) {
- if (it_loop.Current()->GetLoopInformation()->IsIrreducible()) {
- contains_irreducible_loop = true;
- break;
- }
- }
- }
-
for (HBlocksInLoopIterator it_loop(*loop_info); !it_loop.Done(); it_loop.Advance()) {
HBasicBlock* inner = it_loop.Current();
DCHECK(inner->IsInLoop());
@@ -123,11 +113,12 @@
visited->SetBit(inner->GetBlockId());
}
- if (contains_irreducible_loop) {
+ if (loop_info->ContainsIrreducibleLoop()) {
// We cannot licm in an irreducible loop, or in a natural loop containing an
// irreducible loop.
continue;
}
+ DCHECK(!loop_info->IsIrreducible());
// We can move an instruction that can throw only if it is the first
// throwing instruction in the loop. Note that the first potentially