Refactor Lo and Hi out of Variable.

src/IceTargetLowering.h

 //===- subzero/src/IceTargetLowering.h - Lowering interface -----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 163 matching lines @@
   /// a Type is not provided, a target-specific default type is used.
   virtual Variable *getPhysicalRegister(SizeT RegNum,
                                         Type Ty = IceType_void) = 0;
   /// Returns a printable name for the register.
   virtual IceString getRegName(SizeT RegNum, Type Ty) const = 0;
 
   virtual bool hasFramePointer() const { return false; }
   virtual SizeT getFrameOrStackReg() const = 0;
   virtual size_t typeWidthInBytesOnStack(Type Ty) const = 0;
 
+  /// Return whether a 64-bit Variable should be split into a Variable64On32.
+  virtual bool shouldSplitToVariable64On32(Type Ty) const = 0;
+
   bool hasComputedFrame() const { return HasComputedFrame; }
   /// Returns true if this function calls a function that has the "returns
   /// twice" attribute.
   bool callsReturnsTwice() const { return CallsReturnsTwice; }
   void setCallsReturnsTwice(bool RetTwice) { CallsReturnsTwice = RetTwice; }
   int32_t getStackAdjustment() const { return StackAdjustment; }
   void updateStackAdjustment(int32_t Offset) { StackAdjustment += Offset; }
   void resetStackAdjustment() { StackAdjustment = 0; }
   SizeT makeNextLabelNumber() { return NextLabelNumber++; }
   SizeT makeNextJumpTableNumber() { return NextJumpTableNumber++; }
@@ skipping 256 matching lines @@
   virtual void lower() {}
 
 protected:
   explicit TargetHeaderLowering(GlobalContext *Ctx) : Ctx(Ctx) {}
   GlobalContext *Ctx;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERING_H