[AMDGPU] Use MCRegister instead of unsigned. NFC (#167558)

Author: topperc

llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp

@@ -1865,7 +1865,7 @@ class AMDGPUAsmParser : public MCTargetAsmParser {
   unsigned getConstantBusLimit(unsigned Opcode) const;
   bool usesConstantBus(const MCInst &Inst, unsigned OpIdx);
   bool isInlineConstant(const MCInst &Inst, unsigned OpIdx) const;
-  unsigned findImplicitSGPRReadInVOP(const MCInst &Inst) const;
+  MCRegister findImplicitSGPRReadInVOP(const MCInst &Inst) const;
 
   bool isSupportedMnemo(StringRef Mnemo,
                         const FeatureBitset &FBS);
@@ -3665,7 +3665,8 @@ StringRef AMDGPUAsmParser::getMatchedVariantName() const {
   return "";
 }
 
-unsigned AMDGPUAsmParser::findImplicitSGPRReadInVOP(const MCInst &Inst) const {
+MCRegister
+AMDGPUAsmParser::findImplicitSGPRReadInVOP(const MCInst &Inst) const {
   const MCInstrDesc &Desc = MII.get(Inst.getOpcode());
   for (MCPhysReg Reg : Desc.implicit_uses()) {
     switch (Reg) {
@@ -3679,7 +3680,7 @@ unsigned AMDGPUAsmParser::findImplicitSGPRReadInVOP(const MCInst &Inst) const {
       break;
     }
   }
-  return AMDGPU::NoRegister;
+  return MCRegister();
 }
 
 // NB: This code is correct only when used to check constant
@@ -3854,9 +3855,9 @@ bool AMDGPUAsmParser::validateConstantBusLimitations(
     LiteralSize = 4;
   }
 
-  SmallDenseSet<unsigned> SGPRsUsed;
-  unsigned SGPRUsed = findImplicitSGPRReadInVOP(Inst);
-  if (SGPRUsed != AMDGPU::NoRegister) {
+  SmallDenseSet<MCRegister> SGPRsUsed;
+  MCRegister SGPRUsed = findImplicitSGPRReadInVOP(Inst);
+  if (SGPRUsed) {
     SGPRsUsed.insert(SGPRUsed);
     ++ConstantBusUseCount;
   }