Subzero: Improve the representation and handling of the FakeKill instruction.

src/IceTargetLoweringX8632.h

 //===- subzero/src/IceTargetLoweringX8632.h - x86-32 lowering ---*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the TargetLoweringX8632 class, which
@@ skipping 466 matching lines @@
   bool IsEbpBasedFrame;
   bool NeedsStackAlignment;
   size_t FrameSizeLocals;
   size_t SpillAreaSizeBytes;
   llvm::SmallBitVector TypeToRegisterSet[IceType_NUM];
   llvm::SmallBitVector ScratchRegs;
   llvm::SmallBitVector RegsUsed;
   SizeT NextLabelNumber;
   bool ComputedLiveRanges;
   VarList PhysicalRegisters[IceType_NUM];
+  VarList FakeKilledScratchRegisters;
   static IceString RegNames[];
 
 private:
   ~TargetX8632() override {}
+  // Ideally, this initialization would be done in the constructor,
+  // but we need to defer it until after the initial CFG is built,
+  // because some of the bitcode reader tests rely on the order that
+  // Variables are created and their default printable names.
+  void initFakeKilledScratchRegisters() {
+    for (SizeT I = 0; I < ScratchRegs.size(); ++I)
+      if (ScratchRegs[I])
+        FakeKilledScratchRegisters.push_back(getPhysicalRegister(I));
+  }
   template <typename T> void emitConstantPool() const;
 };
 
 class TargetGlobalInitX8632 : public TargetGlobalInitLowering {
   TargetGlobalInitX8632(const TargetGlobalInitX8632 &) = delete;
   TargetGlobalInitX8632 &operator=(const TargetGlobalInitX8632 &) = delete;
 
 public:
   static TargetGlobalInitLowering *create(GlobalContext *Ctx) {
     return new TargetGlobalInitX8632(Ctx);
   }
 
   virtual void lower(const VariableDeclaration &Var) final;
 
 protected:
   TargetGlobalInitX8632(GlobalContext *Ctx);
 
 private:
   ~TargetGlobalInitX8632() override {}
 };
 
 template <> void ConstantInteger32::emit(GlobalContext *Ctx) const;
 template <> void ConstantInteger64::emit(GlobalContext *Ctx) const;
 template <> void ConstantFloat::emit(GlobalContext *Ctx) const;
 template <> void ConstantDouble::emit(GlobalContext *Ctx) const;
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX8632_H