ART: Update DCE to work with try/catch

Dead block elimination was previously disabled because it needed
to be updated. With this patch, try/catch blocks can be removed
as a result of a dead if/switch branch.

Change-Id: I3261060bf24fd5fe7bb0f989247f0ef62ec5fd7b

1 files changed, 5 insertions, 7 deletions

diff --git a/compiler/optimizing/dead_code_elimination.cc b/compiler/optimizing/dead_code_elimination.cc
index 9754043f32..02e5dab3d4 100644
--- a/compiler/optimizing/dead_code_elimination.cc
+++ b/compiler/optimizing/dead_code_elimination.cc
@@ -123,20 +123,21 @@ void HDeadCodeElimination::RemoveDeadBlocks() {
   }
 
   // If we removed at least one block, we need to recompute the full
-  // dominator tree.
+  // dominator tree and try block membership.
   if (removed_one_or_more_blocks) {
     graph_->ClearDominanceInformation();
     graph_->ComputeDominanceInformation();
+    graph_->ComputeTryBlockInformation();
   }
 
   // Connect successive blocks created by dead branches. Order does not matter.
   for (HReversePostOrderIterator it(*graph_); !it.Done();) {
     HBasicBlock* block  = it.Current();
-    if (block->IsEntryBlock() || block->GetSuccessors().size() != 1u) {
+    if (block->IsEntryBlock() || !block->GetLastInstruction()->IsGoto()) {
       it.Advance();
       continue;
     }
-    HBasicBlock* successor = block->GetSuccessors()[0];
+    HBasicBlock* successor = block->GetSingleSuccessor();
     if (successor->IsExitBlock() || successor->GetPredecessors().size() != 1u) {
       it.Advance();
       continue;
@@ -176,10 +177,7 @@ void HDeadCodeElimination::RemoveDeadInstructions() {
 }
 
 void HDeadCodeElimination::Run() {
-  if (!graph_->HasTryCatch()) {
-    // TODO: Update dead block elimination and enable for try/catch.
-    RemoveDeadBlocks();
-  }
+  RemoveDeadBlocks();
   SsaRedundantPhiElimination(graph_).Run();
   RemoveDeadInstructions();
 }