A64: Synchronize with r19306.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index b70eedffe057200017a20d37940616e129d02065..8dee39c0b55985a7cbd6dccd41423d0a2c061c40 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -339,6 +339,15 @@ void HBasicBlock::PostProcessLoopHeader(IterationStatement* stmt) {
 }
 
 
+void HBasicBlock::MarkSuccEdgeUnreachable(int succ) {
+  ASSERT(IsFinished());
+  HBasicBlock* succ_block = end()->SuccessorAt(succ);
+
+  ASSERT(succ_block->predecessors()->length() == 1);
+  succ_block->MarkUnreachable();
+}
+
+
 void HBasicBlock::RegisterPredecessor(HBasicBlock* pred) {
   if (HasPredecessor()) {
     // Only loop header blocks can have a predecessor added after