Refactor Lo and Hi out of Variable.

src/IceTargetLoweringX86Base.h

 //===- subzero/src/IceTargetLoweringX86Base.h - x86 lowering ----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 74 matching lines @@
   SizeT getFrameOrStackReg() const override {
     return IsEbpBasedFrame ? Traits::RegisterSet::Reg_ebp
                            : Traits::RegisterSet::Reg_esp;
   }
   size_t typeWidthInBytesOnStack(Type Ty) const override {
     // Round up to the next multiple of WordType bytes.
     const uint32_t WordSizeInBytes = typeWidthInBytes(Traits::WordType);
     return Utils::applyAlignment(typeWidthInBytes(Ty), WordSizeInBytes);
   }
 
+  bool shouldSplitToVariable64On32(Type Ty) const override {
+    return Traits::Is64Bit ? false : Ty == IceType_i64;
+  }
+
   SizeT getMinJumpTableSize() const override { return 4; }
 
   void emitVariable(const Variable *Var) const override;
 
   const char *getConstantPrefix() const final { return "$"; }
   void emit(const ConstantUndef *C) const final;
   void emit(const ConstantInteger32 *C) const final;
   void emit(const ConstantInteger64 *C) const final;
   void emit(const ConstantFloat *C) const final;
   void emit(const ConstantDouble *C) const final;
 
   void initNodeForLowering(CfgNode *Node) override;
-  /// x86-32: Ensure that a 64-bit Variable has been split into 2 32-bit
-  /// Variables, creating them if necessary. This is needed for all I64
-  /// operations, and it is needed for pushing F64 arguments for function calls
-  /// using the 32-bit push instruction (though the latter could be done by
-  /// directly writing to the stack).
-  ///
-  /// x86-64: Complains loudly if invoked because the cpu can handle 64-bit
-  /// types natively.
-  template <typename T = Traits>
-  typename std::enable_if<!T::Is64Bit, void>::type split64(Variable *Var);
-  template <typename T = Traits>
-  typename std::enable_if<T::Is64Bit, void>::type split64(Variable *) {
-    llvm::report_fatal_error(
-        "Hey, yo! This is x86-64. Watcha doin'? (split64)");
-  }
 
   template <typename T = Traits>
   typename std::enable_if<!T::Is64Bit, Operand>::type *
   loOperand(Operand *Operand);
   template <typename T = Traits>
   typename std::enable_if<T::Is64Bit, Operand>::type *loOperand(Operand *) {
     llvm::report_fatal_error(
         "Hey, yo! This is x86-64. Watcha doin'? (loOperand)");
   }
 
@@ skipping 593 matching lines @@
   }
 
   BoolFolding FoldingInfo;
 };
 } // end of namespace X86Internal
 } // end of namespace Ice
 
 #include "IceTargetLoweringX86BaseImpl.h"
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX86BASE_H