Fix int64 lowering on big-endian architectures.

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"
 #include "src/compiler/node-marker.h"
 #include "src/zone-containers.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 class Int64Lowering {
  public:
   Int64Lowering(Graph* graph, MachineOperatorBuilder* machine,
                 CommonOperatorBuilder* common, Zone* zone,
                 Signature<MachineRepresentation>* signature);
 
   void LowerGraph();
 
   static int GetParameterCountAfterLowering(
       Signature<MachineRepresentation>* signature);
 
+  static int GetLowerWordOffset() {

[titzer, 2016/06/21 21:22:59]

Can you move these into the CC file?

+#if defined(V8_TARGET_LITTLE_ENDIAN)
+    return 0;
+#elif defined(V8_TARGET_BIG_ENDIAN)
+    return 4;
+#endif
+  }
+
+  static int GetHigherWordOffset() {
+#if defined(V8_TARGET_LITTLE_ENDIAN)
+    return 4;
+#elif defined(V8_TARGET_BIG_ENDIAN)
+    return 0;
+#endif
+  }
+
  private:
   enum class State : uint8_t { kUnvisited, kOnStack, kVisited };
 
   struct Replacement {
     Node* low;
     Node* high;
   };
 
   Zone* zone() const { return zone_; }
   Graph* graph() const { return graph_; }
@@ skipping 30 matching lines @@
   Replacement* replacements_;
   Signature<MachineRepresentation>* signature_;
   Node* placeholder_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INT64_LOWERING_H_