[turbofan] Add support for transitioning stores to double fields.

src/code-stubs.h

 // Copyright 2012 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_CODE_STUBS_H_
 #define V8_CODE_STUBS_H_
 
 #include "src/allocation.h"
 #include "src/assembler.h"
 #include "src/codegen.h"
@@ skipping 43 matching lines @@
   V(ToNumber)                               \
   V(ToLength)                               \
   V(ToString)                               \
   V(ToObject)                               \
   V(VectorStoreICTrampoline)                \
   V(VectorKeyedStoreICTrampoline)           \
   V(VectorStoreIC)                          \
   V(VectorKeyedStoreIC)                     \
   /* HydrogenCodeStubs */                   \
   V(AllocateHeapNumber)                     \
+  V(AllocateMutableHeapNumber)              \
   V(AllocateInNewSpace)                     \
   V(ArrayNArgumentsConstructor)             \
   V(ArrayNoArgumentConstructor)             \
   V(ArraySingleArgumentConstructor)         \
   V(BinaryOpIC)                             \
   V(BinaryOpWithAllocationSite)             \
   V(CompareNilIC)                           \
   V(CreateAllocationSite)                   \
   V(CreateWeakCell)                         \
   V(ElementsTransitionAndStore)             \
@@ skipping 2577 matching lines @@
  public:
   explicit AllocateHeapNumberStub(Isolate* isolate)
       : HydrogenCodeStub(isolate) {}
 
  private:
   DEFINE_CALL_INTERFACE_DESCRIPTOR(AllocateHeapNumber);
   DEFINE_HYDROGEN_CODE_STUB(AllocateHeapNumber, HydrogenCodeStub);
 };
 
 
+class AllocateMutableHeapNumberStub final : public HydrogenCodeStub {
+ public:
+  explicit AllocateMutableHeapNumberStub(Isolate* isolate)
+      : HydrogenCodeStub(isolate) {}
+
+ private:
+  DEFINE_CALL_INTERFACE_DESCRIPTOR(AllocateMutableHeapNumber);
+  DEFINE_HYDROGEN_CODE_STUB(AllocateMutableHeapNumber, HydrogenCodeStub);
+};
+
+
 class AllocateInNewSpaceStub final : public HydrogenCodeStub {
  public:
   explicit AllocateInNewSpaceStub(Isolate* isolate)
       : HydrogenCodeStub(isolate) {}
 
  private:
   DEFINE_CALL_INTERFACE_DESCRIPTOR(AllocateInNewSpace);
   DEFINE_HYDROGEN_CODE_STUB(AllocateInNewSpace, HydrogenCodeStub);
 };
 
@@ skipping 448 matching lines @@
 #undef DEFINE_HYDROGEN_CODE_STUB
 #undef DEFINE_CODE_STUB
 #undef DEFINE_CODE_STUB_BASE
 
 extern Representation RepresentationFromType(Type* type);
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CODE_STUBS_H_