Fix bug with GVN on array loads.

src/x64/lithium-x64.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1608 matching lines @@
 
 
 LInstruction* LChunkBuilder::DoValueOf(HValueOf* instr) {
   LOperand* object = UseRegister(instr->value());
   LValueOf* result = new LValueOf(object);
   return AssignEnvironment(DefineSameAsFirst(result));
 }
 
 
 LInstruction* LChunkBuilder::DoBoundsCheck(HBoundsCheck* instr) {
-  return AssignEnvironment(new LBoundsCheck(UseRegisterAtStart(instr->index()),
-                                            Use(instr->length())));
+  LBoundsCheck* result = new LBoundsCheck(UseRegisterAtStart(instr->index()),
+                                          Use(instr->length()));
+  return AssignEnvironment(DefineSameAsFirst(result));
 }
 
 
 LInstruction* LChunkBuilder::DoAbnormalExit(HAbnormalExit* instr) {
   // The control instruction marking the end of a block that completed
   // abruptly (e.g., threw an exception).  There is nothing specific to do.
   return NULL;
 }
 
 
@@ skipping 593 matching lines @@
   LOperand* key = UseOrConstantAtStart(instr->key());
   LOperand* object = UseOrConstantAtStart(instr->object());
   LIn* result = new LIn(key, object);
   return MarkAsCall(DefineFixed(result, rax), instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64