[turbofan]: Elide extra move when accessing stack or frame register

src/frames.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_FRAMES_H_
 #define V8_FRAMES_H_
 
 #include "src/allocation.h"
 #include "src/handles.h"
 #include "src/safepoint-table.h"
@@ skipping 448 matching lines @@
   int ComputeExpressionsCount() const;
   static Object* GetExpression(Address fp, int index);
 
   virtual void SetCallerFp(Address caller_fp);
 
   static StandardFrame* cast(StackFrame* frame) {
     DCHECK(frame->is_standard());
     return static_cast<StandardFrame*>(frame);
   }
 
+  // Architecture-specific register description.
+  static Register sp_register();
+  static Register fp_register();
+
  protected:
   inline explicit StandardFrame(StackFrameIteratorBase* iterator);
 
   virtual void ComputeCallerState(State* state) const;
 
   // Accessors.
   inline Address caller_fp() const;
   inline Address caller_pc() const;
 
   // Computes the address of the PC field in the standard frame given
@@ skipping 116 matching lines @@
 
   // Build a list with summaries for this frame including all inlined frames.
   virtual void Summarize(List<FrameSummary>* frames);
 
   // Lookup exception handler for current {pc}, returns -1 if none found. Also
   // returns the expected number of stack slots at the handler site.
   virtual int LookupExceptionHandlerInTable(
       int* stack_slots, HandlerTable::CatchPrediction* prediction);
 
   // Architecture-specific register description.
-  static Register fp_register();
   static Register context_register();
   static Register constant_pool_pointer_register();
 
   static JavaScriptFrame* cast(StackFrame* frame) {
     DCHECK(frame->is_java_script());
     return static_cast<JavaScriptFrame*>(frame);
   }
 
   static void PrintFunctionAndOffset(JSFunction* function, Code* code,
                                      Address pc, FILE* file,
@@ skipping 316 matching lines @@
 };
 
 
 // Reads all frames on the current stack and copies them into the current
 // zone memory.
 Vector<StackFrame*> CreateStackMap(Isolate* isolate, Zone* zone);
 
 } }  // namespace v8::internal
 
 #endif  // V8_FRAMES_H_