Reland Vector ICs: platform support for vector-based stores.

src/ic/x64/access-compiler-x64.cc

 // 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/ic/access-compiler.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 13 matching lines @@
   Register name = LoadDescriptor::NameRegister();
   static Register registers[] = {receiver, name, rax, rbx, rdi, r8};
   return registers;
 }
 
 
 Register* PropertyAccessCompiler::store_calling_convention() {
   // receiver, name, scratch1, scratch2, scratch3.
   Register receiver = StoreDescriptor::ReceiverRegister();
   Register name = StoreDescriptor::NameRegister();
-  DCHECK(rbx.is(StoreTransitionDescriptor::MapRegister()));
+  DCHECK(FLAG_vector_stores ||
+         rbx.is(StoreTransitionDescriptor::MapRegister()));
   static Register registers[] = {receiver, name, rbx, rdi, r8};
   return registers;
 }
 
 
 #undef __
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64