Subzero: Make -reg-use and -reg-exclude specific to register class.

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 78 matching lines @@
   void translateOm1() override;
   void translateO2() override;
   void doLoadOpt();
   bool doBranchOpt(Inst *I, const CfgNode *NextNode) override;
 
   SizeT getNumRegisters() const override {
     return Traits::RegisterSet::Reg_NUM;
   }
   Variable *getPhysicalRegister(SizeT RegNum, Type Ty = IceType_void) override;
   IceString getRegName(SizeT RegNum, Type Ty) const override;
+  static IceString getRegClassName(RegClass C) {
+    auto ClassNum = static_cast<RegClassX86>(C);
+    assert(ClassNum < RCX86_NUM);
+    switch (ClassNum) {
+    default:
+      return regClassString(C);
+    case RCX86_Is64To8:
+      return "i64to8"; // 64-bit GPR truncable to i8
+    case RCX86_Is32To8:
+      return "i32to8"; // 32-bit GPR truncable to i8
+    case RCX86_Is16To8:
+      return "i16to8"; // 16-bit GPR truncable to i8
+    case RCX86_IsTrunc8Rcvr:
+      return "i8from"; // 8-bit GPR truncable from wider GPRs
+    case RCX86_IsAhRcvr:
+      return "i8fromah"; // 8-bit GPR that ah can be assigned to
+    }
+  }
   llvm::SmallBitVector getRegisterSet(RegSetMask Include,
                                       RegSetMask Exclude) const override;
   const llvm::SmallBitVector &
   getRegistersForVariable(const Variable *Var) const override {
     RegClass RC = Var->getRegClass();
     assert(static_cast<RegClassX86>(RC) < RCX86_NUM);
     return TypeToRegisterSet[RC];
   }
 
   const llvm::SmallBitVector &getAliasesForRegister(SizeT Reg) const override {
@@ skipping 910 matching lines @@
 
   static FixupKind PcRelFixup;
   static FixupKind AbsFixup;
 };
 } // end of namespace X86NAMESPACE
 } // end of namespace Ice
 
 #include "IceTargetLoweringX86BaseImpl.h"
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX86BASE_H