[turbofan] Combine JSToNumber and ChangeTaggedToFloat64 for fast SMI case.

src/compiler/change-lowering.h

 // 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.
 
 #ifndef V8_COMPILER_CHANGE_LOWERING_H_
 #define V8_COMPILER_CHANGE_LOWERING_H_
 
 #include "src/compiler/graph-reducer.h"
 
 namespace v8 {
@@ skipping 13 matching lines @@
   virtual ~ChangeLowering();
 
   virtual Reduction Reduce(Node* node) OVERRIDE;
 
  private:
   Node* HeapNumberValueIndexConstant();
   Node* SmiMaxValueConstant();
   Node* SmiShiftBitsConstant();
 
   Node* AllocateHeapNumberWithValue(Node* value, Node* control);
+  Node* ChangeInt32ToFloat64(Node* value);
+  Node* ChangeSmiToFloat64(Node* value);
   Node* ChangeSmiToInt32(Node* value);
+  Node* ChangeUint32ToFloat64(Node* value);
+  Node* ChangeUint32ToSmi(Node* value);
   Node* LoadHeapNumberValue(Node* value, Node* control);
+  Node* TestNotSmi(Node* value);
+  Node* Uint32LessThanOrEqual(Node* lhs, Node* rhs);
 
-  Reduction ChangeBitToBool(Node* val, Node* control);
-  Reduction ChangeBoolToBit(Node* val);
-  Reduction ChangeFloat64ToTagged(Node* val, Node* control);
-  Reduction ChangeInt32ToTagged(Node* val, Node* control);
-  Reduction ChangeTaggedToFloat64(Node* val, Node* control);
-  Reduction ChangeTaggedToUI32(Node* val, Node* control, Signedness signedness);
-  Reduction ChangeUint32ToTagged(Node* val, Node* control);
+  Reduction ChangeBitToBool(Node* value, Node* control);
+  Reduction ChangeBoolToBit(Node* value);
+  Reduction ChangeFloat64ToTagged(Node* value, Node* control);
+  Reduction ChangeInt32ToTagged(Node* value, Node* control);
+  Reduction ChangeTaggedToFloat64(Node* value, Node* control);
+  Reduction ChangeTaggedToUI32(Node* value, Node* control,
+                               Signedness signedness);
+  Reduction ChangeUint32ToTagged(Node* value, Node* control);
 
   Graph* graph() const;
   Isolate* isolate() const;
   JSGraph* jsgraph() const { return jsgraph_; }
   Linkage* linkage() const { return linkage_; }
   CommonOperatorBuilder* common() const;
   MachineOperatorBuilder* machine() const;
 
   JSGraph* jsgraph_;
   Linkage* linkage_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_CHANGE_LOWERING_H_