[RISCV] Replace uses of RISCV::NoRegister with Register() or isValid. NFC

[topperc]

No description provided.

[llvmbot]

@llvm/pr-subscribers-backend-risc-v

Author: Craig Topper (topperc)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/161781.diff

5 Files Affected:

• (modified) llvm/lib/Target/RISCV/RISCVFrameLowering.cpp (+1-1)
• (modified) llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp (+3-3)
• (modified) llvm/lib/Target/RISCV/RISCVInstrInfo.cpp (+2-2)
• (modified) llvm/lib/Target/RISCV/RISCVMakeCompressible.cpp (+2-2)
• (modified) llvm/lib/Target/RISCV/RISCVVectorPeephole.cpp (+8-8)

diff --git a/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp b/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
index 7d4535ad46916..a73e24f102b6c 100644
--- a/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
@@ -1560,7 +1560,7 @@ static MCRegister getRVVBaseRegister(const RISCVRegisterInfo &TRI,
   MCRegister BaseReg = TRI.getSubReg(Reg, RISCV::sub_vrm1_0);
   // If it's not a grouped vector register, it doesn't have subregister, so
   // the base register is just itself.
-  if (BaseReg == RISCV::NoRegister)
+  if (!BaseReg)
     BaseReg = Reg;
   return BaseReg;
 }
diff --git a/llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp b/llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp
index 6a6ead2697591..9062e3706e487 100644
--- a/llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp
+++ b/llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp
@@ -128,7 +128,7 @@ static bool hasUndefinedPassthru(const MachineInstr &MI) {
   // All undefined passthrus should be $noreg: see
   // RISCVDAGToDAGISel::doPeepholeNoRegPassThru
   const MachineOperand &UseMO = MI.getOperand(UseOpIdx);
-  return UseMO.getReg() == RISCV::NoRegister || UseMO.isUndef();
+  return !UseMO.getReg() || UseMO.isUndef();
 }
 
 /// Return true if \p MI is a copy that will be lowered to one or more vmvNr.vs.
@@ -1454,7 +1454,7 @@ void RISCVInsertVSETVLI::emitVSETVLIs(MachineBasicBlock &MBB) {
           Register Reg = VLOp.getReg();
 
           // Erase the AVL operand from the instruction.
-          VLOp.setReg(RISCV::NoRegister);
+          VLOp.setReg(Register());
           VLOp.setIsKill(false);
           if (LIS) {
             LiveInterval &LI = LIS->getInterval(Reg);
@@ -1663,7 +1663,7 @@ void RISCVInsertVSETVLI::coalesceVSETVLIs(MachineBasicBlock &MBB) const {
     if (!MO.isReg() || !MO.getReg().isVirtual())
       return;
     Register OldVLReg = MO.getReg();
-    MO.setReg(RISCV::NoRegister);
+    MO.setReg(Register());
 
     if (LIS)
       LIS->shrinkToUses(&LIS->getInterval(OldVLReg));
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp b/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
index 1e6b04f8a4281..25ebd7946f822 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
@@ -1364,7 +1364,7 @@ void RISCVInstrInfo::insertIndirectBranch(MachineBasicBlock &MBB,
       RS->scavengeRegisterBackwards(RISCV::GPRRegClass, MI.getIterator(),
                                     /*RestoreAfter=*/false, /*SpAdj=*/0,
                                     /*AllowSpill=*/false);
-  if (TmpGPR != RISCV::NoRegister)
+  if (TmpGPR)
     RS->setRegUsed(TmpGPR);
   else {
     // The case when there is no scavenged register needs special handling.
@@ -3021,7 +3021,7 @@ bool RISCVInstrInfo::verifyInstruction(const MachineInstr &MI,
       ErrInfo = "Invalid operand type for VL operand";
       return false;
     }
-    if (Op.isReg() && Op.getReg() != RISCV::NoRegister) {
+    if (Op.isReg() && Op.getReg().isValid()) {
       const MachineRegisterInfo &MRI = MI.getParent()->getParent()->getRegInfo();
       auto *RC = MRI.getRegClass(Op.getReg());
       if (!RISCV::GPRRegClass.hasSubClassEq(RC)) {
diff --git a/llvm/lib/Target/RISCV/RISCVMakeCompressible.cpp b/llvm/lib/Target/RISCV/RISCVMakeCompressible.cpp
index f8d33ae8d24ca..54569b1f7aaf3 100644
--- a/llvm/lib/Target/RISCV/RISCVMakeCompressible.cpp
+++ b/llvm/lib/Target/RISCV/RISCVMakeCompressible.cpp
@@ -259,7 +259,7 @@ static RegImmPair getRegImmPairPreventingCompression(const MachineInstr &MI) {
   if (isCompressibleLoad(MI) || isCompressibleStore(MI)) {
     const MachineOperand &MOImm = MI.getOperand(2);
     if (!MOImm.isImm())
-      return RegImmPair(RISCV::NoRegister, 0);
+      return RegImmPair(Register(), 0);
 
     int64_t Offset = MOImm.getImm();
     int64_t NewBaseAdjust = getBaseAdjustForCompression(Offset, Opcode);
@@ -292,7 +292,7 @@ static RegImmPair getRegImmPairPreventingCompression(const MachineInstr &MI) {
       }
     }
   }
-  return RegImmPair(RISCV::NoRegister, 0);
+  return RegImmPair(Register(), 0);
 }
 
 // Check all uses after FirstMI of the given register, keeping a vector of
diff --git a/llvm/lib/Target/RISCV/RISCVVectorPeephole.cpp b/llvm/lib/Target/RISCV/RISCVVectorPeephole.cpp
index ffba2843bde1f..8f1b4cac4b3bc 100644
--- a/llvm/lib/Target/RISCV/RISCVVectorPeephole.cpp
+++ b/llvm/lib/Target/RISCV/RISCVVectorPeephole.cpp
@@ -382,7 +382,7 @@ bool RISCVVectorPeephole::convertAllOnesVMergeToVMv(MachineInstr &MI) const {
   // vmv.v.v doesn't have a mask operand, so we may be able to inflate the
   // register class for the destination and passthru operands e.g. VRNoV0 -> VR
   MRI->recomputeRegClass(MI.getOperand(0).getReg());
-  if (MI.getOperand(1).getReg() != RISCV::NoRegister)
+  if (MI.getOperand(1).getReg())
     MRI->recomputeRegClass(MI.getOperand(1).getReg());
   return true;
 }
@@ -448,7 +448,7 @@ bool RISCVVectorPeephole::convertSameMaskVMergeToVMv(MachineInstr &MI) {
   Register FalseReg = MI.getOperand(2).getReg();
   if (TruePassthruReg != FalseReg) {
     // If True's passthru is undef see if we can change it to False
-    if (TruePassthruReg != RISCV::NoRegister ||
+    if (TruePassthruReg.isValid() ||
         !MRI->hasOneUse(MI.getOperand(3).getReg()) ||
         !ensureDominates(MI.getOperand(2), *True))
       return false;
@@ -467,7 +467,7 @@ bool RISCVVectorPeephole::convertSameMaskVMergeToVMv(MachineInstr &MI) {
   // vmv.v.v doesn't have a mask operand, so we may be able to inflate the
   // register class for the destination and passthru operands e.g. VRNoV0 -> VR
   MRI->recomputeRegClass(MI.getOperand(0).getReg());
-  if (MI.getOperand(1).getReg() != RISCV::NoRegister)
+  if (MI.getOperand(1).getReg())
     MRI->recomputeRegClass(MI.getOperand(1).getReg());
   return true;
 }
@@ -517,7 +517,7 @@ bool RISCVVectorPeephole::convertToUnmasked(MachineInstr &MI) const {
   if (RISCVII::isFirstDefTiedToFirstUse(MaskedMCID)) {
     unsigned PassthruOpIdx = MI.getNumExplicitDefs();
     if (HasPassthru) {
-      if (MI.getOperand(PassthruOpIdx).getReg() != RISCV::NoRegister)
+      if (MI.getOperand(PassthruOpIdx).getReg())
         MRI->recomputeRegClass(MI.getOperand(PassthruOpIdx).getReg());
     } else
       MI.removeOperand(PassthruOpIdx);
@@ -576,7 +576,7 @@ static bool dominates(MachineBasicBlock::const_iterator A,
 bool RISCVVectorPeephole::ensureDominates(const MachineOperand &MO,
                                           MachineInstr &Src) const {
   assert(MO.getParent()->getParent() == Src.getParent());
-  if (!MO.isReg() || MO.getReg() == RISCV::NoRegister)
+  if (!MO.isReg() || !MO.getReg())
     return true;
 
   MachineInstr *Def = MRI->getVRegDef(MO.getReg());
@@ -593,7 +593,7 @@ bool RISCVVectorPeephole::ensureDominates(const MachineOperand &MO,
 bool RISCVVectorPeephole::foldUndefPassthruVMV_V_V(MachineInstr &MI) {
   if (RISCV::getRVVMCOpcode(MI.getOpcode()) != RISCV::VMV_V_V)
     return false;
-  if (MI.getOperand(1).getReg() != RISCV::NoRegister)
+  if (MI.getOperand(1).getReg().isValid())
     return false;
 
   // If the input was a pseudo with a policy operand, we can give it a tail
@@ -654,7 +654,7 @@ bool RISCVVectorPeephole::foldVMV_V_V(MachineInstr &MI) {
 
   // Src needs to have the same passthru as VMV_V_V
   MachineOperand &SrcPassthru = Src->getOperand(Src->getNumExplicitDefs());
-  if (SrcPassthru.getReg() != RISCV::NoRegister &&
+  if (SrcPassthru.getReg().isValid() &&
       SrcPassthru.getReg() != Passthru.getReg())
     return false;
 
@@ -672,7 +672,7 @@ bool RISCVVectorPeephole::foldVMV_V_V(MachineInstr &MI) {
   if (SrcPassthru.getReg() != Passthru.getReg()) {
     SrcPassthru.setReg(Passthru.getReg());
     // If Src is masked then its passthru needs to be in VRNoV0.
-    if (Passthru.getReg() != RISCV::NoRegister)
+    if (Passthru.getReg())
       MRI->constrainRegClass(
           Passthru.getReg(),
           TII->getRegClass(Src->getDesc(), SrcPassthru.getOperandNo(), TRI));

[lenary]

Two quibbles, but neither of them major enough to block this.

I don't understand when you've chosen to use Register::operator bool and Register::isValid, especially when using one of those two on the result of MCOperand::getReg.

[lenary]

Quibble - MCRegister doesn't have an operator bool, you're using the operator unsigned here, and then assuming that NoRegister has falsey value - but using RISCV::NoRegister is a way to remove that assumption, or you could do the following:

Suggested change

	if (!BaseReg)
	if (!BaseReg.isValid())

[topperc]

In my prior conversations with @arsenm, I think we decided that we will add an operator bool when we remove operator unsigned.