Adding Smi support to Add, Sub, Mul, and Bitwise

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 610cb87f38dbba773079acf1a7ef43f329256b3b..aa44e217dc5208dce74f3931a92dbfb597edcc38 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -1885,11 +1885,8 @@ HValue* HGraphBuilder::JSArrayBuilder::EstablishAllocationSize(
     base_size += AllocationMemento::kSize;
   }
 
-  if (IsFastDoubleElementsKind(kind_)) {
-    base_size += FixedDoubleArray::kHeaderSize;
-  } else {
-    base_size += FixedArray::kHeaderSize;
-  }
+  STATIC_ASSERT(FixedDoubleArray::kHeaderSize == FixedArray::kHeaderSize);
+  base_size += FixedArray::kHeaderSize;
 
   HInstruction* elements_size_value =
       builder()->Add<HConstant>(elements_size());
@@ -3802,7 +3799,6 @@ void HOptimizedGraphBuilder::VisitForInStatement(ForInStatement* stmt) {
                                         environment()->LookupContext(),
                                         current_index,
                                         graph()->GetConstant1());
-    new_index->AssumeRepresentation(Representation::Integer32());
     PushAndAdd(new_index);
     body_exit = current_block();
   }