[turbofan] Add support for storing to double fields.

src/compiler/common-operator-reducer.cc

Index: src/compiler/common-operator-reducer.cc
diff --git a/src/compiler/common-operator-reducer.cc b/src/compiler/common-operator-reducer.cc
index e4af2ad1f9b352a7654bdb1ea93f6f9cc775ddf9..e3c2ecad6ea10fe810e7c9e3e382fe9e5e0927e9 100644
--- a/src/compiler/common-operator-reducer.cc
+++ b/src/compiler/common-operator-reducer.cc
@@ -67,6 +67,8 @@ Reduction CommonOperatorReducer::Reduce(Node* node) {
       return ReduceReturn(node);
     case IrOpcode::kSelect:
       return ReduceSelect(node);
+    case IrOpcode::kGuard:
+      return ReduceGuard(node);
     default:
       break;
   }
@@ -358,6 +360,16 @@ Reduction CommonOperatorReducer::ReduceSelect(Node* node) {
 }
 
 
+Reduction CommonOperatorReducer::ReduceGuard(Node* node) {
+  DCHECK_EQ(IrOpcode::kGuard, node->opcode());
+  Node* const input = NodeProperties::GetValueInput(node, 0);
+  Type* const input_type = NodeProperties::GetTypeOrAny(input);
+  Type* const guard_type = OpParameter<Type*>(node);
+  if (input_type->Is(guard_type)) return Replace(input);
+  return NoChange();
+}
+
+
 Reduction CommonOperatorReducer::Change(Node* node, Operator const* op,
                                         Node* a) {
   node->ReplaceInput(0, a);