Handle COW-arrays correctly when converting smi->double fast elements.

src/x64/code-stubs-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 5671 matching lines @@
   // GenerateStoreField calls the stub with two different permutations of
   // registers.  This is the second.
   { rbx, rcx, rdx, EMIT_REMEMBERED_SET },
   // StoreIC::GenerateNormal via GenerateDictionaryStore.
   { rbx, r8, r9, EMIT_REMEMBERED_SET },
   // KeyedStoreIC::GenerateGeneric.
   { rbx, rdx, rcx, EMIT_REMEMBERED_SET},
   // KeyedStoreStubCompiler::GenerateStoreFastElement.
   { rdi, rdx, rcx, EMIT_REMEMBERED_SET},
   // ElementsTransitionGenerator::GenerateSmiOnlyToObject
+  // and ElementsTransitionGenerator::GenerateSmiOnlyToObject
   // and ElementsTransitionGenerator::GenerateDoubleToObject
   { rdx, rbx, rdi, EMIT_REMEMBERED_SET},
+  // ElementsTransitionGenerator::GenerateSmiOnlyToDouble
+  // and ElementsTransitionGenerator::GenerateDoubleToObject
+  { rdx, r11, r15, EMIT_REMEMBERED_SET},
   // ElementsTransitionGenerator::GenerateDoubleToObject
-  { rax, r11, r15, EMIT_REMEMBERED_SET},
-  { rdx, rax, rdi, EMIT_REMEMBERED_SET},
+  { r11, rax, r15, EMIT_REMEMBERED_SET},
   // Null termination.
   { no_reg, no_reg, no_reg, EMIT_REMEMBERED_SET}
 };
 
 
 bool RecordWriteStub::IsPregenerated() {
   for (AheadOfTimeWriteBarrierStubList* entry = kAheadOfTime;
        !entry->object.is(no_reg);
        entry++) {
     if (object_.is(entry->object) &&
@@ skipping 232 matching lines @@
   __ bind(&need_incremental);
 
   // Fall through when we need to inform the incremental marker.
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64