Use hydrogen accessor instead of copying members.

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index 03b738ec49b2f0cffb1d897ece3677ae32f9c8ff..b8184f8384eae58ec96a295685f41293602c012b 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -1285,12 +1285,7 @@ LInstruction* LChunkBuilder::DoCompareMapAndBranch(
     HCompareMapAndBranch* instr) {
   ASSERT(instr->value()->representation().IsTagged());
   LOperand* value = UseRegisterAtStart(instr->value());
-  HBasicBlock* first = instr->FirstSuccessor();
-  HBasicBlock* second = instr->SecondSuccessor();
-  return new LCmpMapAndBranch(value,
-                              instr->map(),
-                              first->block_id(),
-                              second->block_id());
+  return new LCmpMapAndBranch(value);
 }