Refactor Lo and Hi out of Variable.

src/IceTargetLoweringARM32.h

 //===- subzero/src/IceTargetLoweringARM32.h - ARM32 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 67 matching lines @@
     return UsesFramePointer ? RegARM32::Reg_fp : RegARM32::Reg_sp;
   }
   SizeT getReservedTmpReg() const { return RegARM32::Reg_ip; }
 
   size_t typeWidthInBytesOnStack(Type Ty) const override {
     // Round up to the next multiple of 4 bytes. In particular, i1, i8, and i16
     // are rounded up to 4 bytes.
     return (typeWidthInBytes(Ty) + 3) & ~3;
   }
 
+  bool shouldSplitToVariable64On32(Type Ty) const override {
+    return Ty == IceType_i64;
+  }
+
   // TODO(ascull): what size is best for ARM?
   SizeT getMinJumpTableSize() const override { return 3; }
   void emitJumpTable(const Cfg *Func,
                      const InstJumpTable *JumpTable) const override;
 
   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 lowerArguments() override;
   void addProlog(CfgNode *Node) override;
   void addEpilog(CfgNode *Node) override;
 
-  /// 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.
-  void split64(Variable *Var);
   Operand *loOperand(Operand *Operand);
   Operand *hiOperand(Operand *Operand);
   void finishArgumentLowering(Variable *Arg, Variable *FramePtr,
                               size_t BasicFrameOffset, size_t &InArgsSizeBytes);
 
   bool hasCPUFeature(TargetARM32Features::ARM32InstructionSet I) const {
     return CPUFeatures.hasFeature(I);
   }
   Operand *legalizeUndef(Operand *From, int32_t RegNum = Variable::NoRegister);
 
@@ skipping 433 matching lines @@
 
 private:
   ~TargetHeaderARM32() = default;
 
   TargetARM32Features CPUFeatures;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGARM32_H