[wasm] Change the default lowering of stores.

src/compiler/int64-lowering.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_INT64_LOWERING_H_
 #define V8_COMPILER_INT64_LOWERING_H_
 
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
 #include "src/compiler/machine-operator.h"
@@ skipping 29 matching lines @@
 
   Zone* zone() const { return zone_; }
   Graph* graph() const { return graph_; }
   MachineOperatorBuilder* machine() const { return machine_; }
   CommonOperatorBuilder* common() const { return common_; }
   Signature<MachineRepresentation>* signature() const { return signature_; }
 
   void PrepareReplacements(Node* node);
   void PushNode(Node* node);
   void LowerNode(Node* node);
-  bool DefaultLowering(Node* node);
+  bool DefaultLowering(Node* node, bool low_word_only = false);
   void LowerComparison(Node* node, const Operator* signed_op,
                        const Operator* unsigned_op);
   void PrepareProjectionReplacements(Node* node);
 
   void ReplaceNode(Node* old, Node* new_low, Node* new_high);
   bool HasReplacementLow(Node* node);
   Node* GetReplacementLow(Node* node);
   bool HasReplacementHigh(Node* node);
   Node* GetReplacementHigh(Node* node);
   void PreparePhiReplacement(Node* phi);
@@ skipping 13 matching lines @@
   Replacement* replacements_;
   Signature<MachineRepresentation>* signature_;
   Node* placeholder_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INT64_LOWERING_H_