Fix the loop-builder to tag the entire body as part of the loop.

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 939 matching lines @@
       increment_ = HAdd::New(zone(), context_, phi_, one);
     } else {
       increment_ = HSub::New(zone(), context_, phi_, one);
     }
     increment_->ClearFlag(HValue::kCanOverflow);
     builder_->AddInstruction(increment_);
   }
 
   // Push the new increment value on the expression stack to merge into the phi.
   builder_->environment()->Push(increment_);
-  builder_->current_block()->GotoNoSimulate(header_block_);
-  header_block_->loop_information()->RegisterBackEdge(body_block_);
+  HBasicBlock* last_block = builder_->current_block();
+  last_block->GotoNoSimulate(header_block_);
+  header_block_->loop_information()->RegisterBackEdge(last_block);
 
   builder_->set_current_block(exit_block_);
   // Pop the phi from the expression stack
   builder_->environment()->Pop();
   finished_ = true;
 }
 
 
 HGraph* HGraphBuilder::CreateGraph() {
   graph_ = new(zone()) HGraph(info_);
@@ skipping 8729 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal