ART: Fix critical edge splitting under try/catch

A critical edge would not be split if the predecessor ends with
TryBoundary. This would eventually trip liveness analysis because
a back edge block would have smaller liveness position than a nested
loop.

Another implication of this change is that an edge between a loop's
pre-header ending with TryBoundary and the header will be split,
guaranteeing that a pre-header always has just one successor.

Bug: 25493695
Bug: 25454012
Change-Id: I5a13b8bb74509b48f5d628906f7158af007f99ae

1 files changed, 6 insertions, 1 deletions

diff --git a/compiler/optimizing/induction_var_analysis_test.cc b/compiler/optimizing/induction_var_analysis_test.cc
index b7262f6b29..5de94f43c9 100644
--- a/compiler/optimizing/induction_var_analysis_test.cc
+++ b/compiler/optimizing/induction_var_analysis_test.cc
@@ -69,10 +69,13 @@ class InductionVarAnalysisTest : public testing::Test {
     entry_ = new (&allocator_) HBasicBlock(graph_);
     graph_->AddBlock(entry_);
     BuildForLoop(0, n);
+    return_ = new (&allocator_) HBasicBlock(graph_);
+    graph_->AddBlock(return_);
     exit_ = new (&allocator_) HBasicBlock(graph_);
     graph_->AddBlock(exit_);
     entry_->AddSuccessor(loop_preheader_[0]);
-    loop_header_[0]->AddSuccessor(exit_);
+    loop_header_[0]->AddSuccessor(return_);
+    return_->AddSuccessor(exit_);
     graph_->SetEntryBlock(entry_);
     graph_->SetExitBlock(exit_);
 
@@ -91,6 +94,7 @@ class InductionVarAnalysisTest : public testing::Test {
     entry_->AddInstruction(new (&allocator_) HStoreLocal(tmp_, constant100_));
     dum_ = new (&allocator_) HLocal(n + 2);
     entry_->AddInstruction(dum_);
+    return_->AddInstruction(new (&allocator_) HReturnVoid());
     exit_->AddInstruction(new (&allocator_) HExit());
 
     // Provide loop instructions.
@@ -177,6 +181,7 @@ class InductionVarAnalysisTest : public testing::Test {
 
   // Fixed basic blocks and instructions.
   HBasicBlock* entry_;
+  HBasicBlock* return_;
   HBasicBlock* exit_;
   HInstruction* parameter_;  // "this"
   HInstruction* constant0_;