Elide unnecessary context reload in generated stubs.

src/x64/lithium-codegen-x64.cc

 // Copyright 2012 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 2423 matching lines @@
     // Preserve the return value on the stack and rely on the runtime
     // call to return the value in the same register.
     __ push(rax);
     __ CallRuntime(Runtime::kTraceExit, 1);
   }
   if (NeedsEagerFrame()) {
     __ movq(rsp, rbp);
     __ pop(rbp);
   }
   if (info()->IsStub()) {
-    __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
     __ Ret(0, r10);
   } else {
     __ Ret((GetParameterCount() + 1) * kPointerSize, rcx);
   }
 }
 
 
 void LCodeGen::DoLoadGlobalCell(LLoadGlobalCell* instr) {
   Register result = ToRegister(instr->result());
   __ LoadGlobalCell(result, instr->hydrogen()->cell());
@@ skipping 3073 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64