AMDGPU: Remove wrapper around TRI::getRegClass

This shadows the member in the base class, but differs slightly
in behavior. The base method doesn't check for the invalid case.

Author: arsenm

llvm/lib/Target/AMDGPU/SIFoldOperands.cpp

@@ -1301,10 +1301,11 @@ void SIFoldOperandsImpl::foldOperand(
         continue;
 
       const int SrcIdx = MovOp == AMDGPU::V_MOV_B16_t16_e64 ? 2 : 1;
-      const TargetRegisterClass *MovSrcRC =
-          TRI->getRegClass(TII->getOpRegClassID(MovDesc.operands()[SrcIdx]));
 
-      if (MovSrcRC) {
+      int16_t RegClassID = TII->getOpRegClassID(MovDesc.operands()[SrcIdx]);
+      if (RegClassID != -1) {
+        const TargetRegisterClass *MovSrcRC = TRI->getRegClass(RegClassID);
+
         if (UseSubReg)
           MovSrcRC = TRI->getMatchingSuperRegClass(SrcRC, MovSrcRC, UseSubReg);
         if (!MRI->constrainRegClass(SrcReg, MovSrcRC))

llvm/lib/Target/AMDGPU/SIInstrInfo.cpp

@@ -5964,7 +5964,7 @@ SIInstrInfo::getRegClass(const MCInstrDesc &TID, unsigned OpNum,
     return nullptr;
   const MCOperandInfo &OpInfo = TID.operands()[OpNum];
   int16_t RegClass = getOpRegClassID(OpInfo);
-  return RI.getRegClass(RegClass);
+  return RegClass < 0 ? nullptr : RI.getRegClass(RegClass);
 }
 
 const TargetRegisterClass *SIInstrInfo::getOpRegClass(const MachineInstr &MI,
@@ -5982,7 +5982,8 @@ const TargetRegisterClass *SIInstrInfo::getOpRegClass(const MachineInstr &MI,
     return RI.getPhysRegBaseClass(Reg);
   }
 
-  return RI.getRegClass(getOpRegClassID(Desc.operands()[OpNo]));
+  int16_t RegClass = getOpRegClassID(Desc.operands()[OpNo]);
+  return RegClass < 0 ? nullptr : RI.getRegClass(RegClass);
 }
 
 void SIInstrInfo::legalizeOpWithMove(MachineInstr &MI, unsigned OpIdx) const {

llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp

@@ -3897,17 +3897,6 @@ const TargetRegisterClass *SIRegisterInfo::getVGPR64Class() const {
                                 : &AMDGPU::VReg_64RegClass;
 }
 
-// FIXME: This should be deleted
-const TargetRegisterClass *
-SIRegisterInfo::getRegClass(unsigned RCID) const {
-  switch ((int)RCID) {
-  case -1:
-    return nullptr;
-  default:
-    return AMDGPUGenRegisterInfo::getRegClass(RCID);
-  }
-}
-
 // Find reaching register definition
 MachineInstr *SIRegisterInfo::findReachingDef(Register Reg, unsigned SubReg,
                                               MachineInstr &Use,

llvm/lib/Target/AMDGPU/SIRegisterInfo.h

@@ -391,8 +391,6 @@ class SIRegisterInfo final : public AMDGPUGenRegisterInfo {
 
   MCRegister getExec() const;
 
-  const TargetRegisterClass *getRegClass(unsigned RCID) const;
-
   // Find reaching register definition
   MachineInstr *findReachingDef(Register Reg, unsigned SubReg,
                                 MachineInstr &Use,