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

src/compiler/instruction.h

Index: src/compiler/instruction.h
diff --git a/src/compiler/instruction.h b/src/compiler/instruction.h
index a87ef7dc9c469f865919aeef34a79fbaacb5e033..4994a2c165430e8a9e62167f2a9a61de92a4eccd 100644
--- a/src/compiler/instruction.h
+++ b/src/compiler/instruction.h
@@ -30,7 +30,15 @@ class InstructionOperand {
 
   // TODO(dcarney): recover bit. INVALID can be represented as UNALLOCATED with
   // kInvalidVirtualRegister and some DCHECKS.
-  enum Kind { INVALID, UNALLOCATED, CONSTANT, IMMEDIATE, ALLOCATED };
+  enum Kind {
+    INVALID,
+    UNALLOCATED,
+    CONSTANT,
+    IMMEDIATE,
+    ALLOCATED,
+    STACK_POINTER,
+    FRAME_POINTER
+  };
 
   InstructionOperand() : InstructionOperand(INVALID) {}
 
@@ -43,6 +51,8 @@ class InstructionOperand {
   INSTRUCTION_OPERAND_PREDICATE(Constant, CONSTANT)
   INSTRUCTION_OPERAND_PREDICATE(Immediate, IMMEDIATE)
   INSTRUCTION_OPERAND_PREDICATE(Allocated, ALLOCATED)
+  INSTRUCTION_OPERAND_PREDICATE(StackPointer, STACK_POINTER)
+  INSTRUCTION_OPERAND_PREDICATE(FramePointer, FRAME_POINTER)
 #undef INSTRUCTION_OPERAND_PREDICATE
 
   inline bool IsRegister() const;
@@ -50,6 +60,10 @@ class InstructionOperand {
   inline bool IsStackSlot() const;
   inline bool IsDoubleStackSlot() const;
 
+  inline bool GeneratesRegister() const {
+    return IsRegister() || IsStackPointer() || IsFramePointer();
+  }
+
   template <typename SubKindOperand>
   static SubKindOperand* New(Zone* zone, const SubKindOperand& op) {
     void* buffer = zone->New(sizeof(op));
@@ -411,6 +425,30 @@ class AllocatedOperand : public InstructionOperand {
 };
 
 
+class StackPointerOperand : public InstructionOperand {
+ public:
+  StackPointerOperand() : InstructionOperand(STACK_POINTER) {}
+
+  static StackPointerOperand* New(Zone* zone) {
+    return InstructionOperand::New(zone, StackPointerOperand());
+  }
+
+  INSTRUCTION_OPERAND_CASTS(StackPointerOperand, STACK_POINTER);
+};
+
+
+class FramePointerOperand : public InstructionOperand {
+ public:
+  FramePointerOperand() : InstructionOperand(FRAME_POINTER) {}
+
+  static FramePointerOperand* New(Zone* zone) {
+    return InstructionOperand::New(zone, FramePointerOperand());
+  }
+
+  INSTRUCTION_OPERAND_CASTS(FramePointerOperand, STACK_POINTER);
+};
+
+
 #undef INSTRUCTION_OPERAND_CASTS