[RISCV][NFC] Use maybe_unused instead of casting to void to fix unuse…

…d variable warning. (llvm#80651)

llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

@@ -1222,8 +1222,8 @@ struct RISCVOperand final : public MCParsedAsmOperand {
     int64_t Imm = 0;
     if (Kind == KindTy::Immediate) {
       RISCVMCExpr::VariantKind VK = RISCVMCExpr::VK_RISCV_None;
-      bool IsConstantImm = evaluateConstantImm(getImm(), Imm, VK);
-      (void)IsConstantImm;
+      [[maybe_unused]] bool IsConstantImm =
+          evaluateConstantImm(getImm(), Imm, VK);
       assert(IsConstantImm && "Invalid VTypeI Operand!");
     } else {
       Imm = getVType();

llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp

@@ -380,8 +380,8 @@ static DecodeStatus decodeRVCInstrRdRs1ImmZero(MCInst &Inst, uint32_t Insn,
                                                uint64_t Address,
                                                const MCDisassembler *Decoder) {
   uint32_t Rd = fieldFromInstruction(Insn, 7, 5);
-  DecodeStatus Result = DecodeGPRNoX0RegisterClass(Inst, Rd, Address, Decoder);
-  (void)Result;
+  [[maybe_unused]] DecodeStatus Result =
+      DecodeGPRNoX0RegisterClass(Inst, Rd, Address, Decoder);
   assert(Result == MCDisassembler::Success && "Invalid register");
   Inst.addOperand(Inst.getOperand(0));
   Inst.addOperand(MCOperand::createImm(0));
@@ -392,8 +392,8 @@ static DecodeStatus decodeCSSPushPopchk(MCInst &Inst, uint32_t Insn,
                                         uint64_t Address,
                                         const MCDisassembler *Decoder) {
   uint32_t Rs1 = fieldFromInstruction(Insn, 7, 5);
-  DecodeStatus Result = DecodeGPRX1X5RegisterClass(Inst, Rs1, Address, Decoder);
-  (void)Result;
+  [[maybe_unused]] DecodeStatus Result =
+      DecodeGPRX1X5RegisterClass(Inst, Rs1, Address, Decoder);
   assert(Result == MCDisassembler::Success && "Invalid register");
   return MCDisassembler::Success;
 }
@@ -404,8 +404,8 @@ static DecodeStatus decodeRVCInstrRdSImm(MCInst &Inst, uint32_t Insn,
   Inst.addOperand(MCOperand::createReg(RISCV::X0));
   uint32_t SImm6 =
       fieldFromInstruction(Insn, 12, 1) << 5 | fieldFromInstruction(Insn, 2, 5);
-  DecodeStatus Result = decodeSImmOperand<6>(Inst, SImm6, Address, Decoder);
-  (void)Result;
+  [[maybe_unused]] DecodeStatus Result =
+      decodeSImmOperand<6>(Inst, SImm6, Address, Decoder);
   assert(Result == MCDisassembler::Success && "Invalid immediate");
   return MCDisassembler::Success;
 }
@@ -417,8 +417,8 @@ static DecodeStatus decodeRVCInstrRdRs1UImm(MCInst &Inst, uint32_t Insn,
   Inst.addOperand(Inst.getOperand(0));
   uint32_t UImm6 =
       fieldFromInstruction(Insn, 12, 1) << 5 | fieldFromInstruction(Insn, 2, 5);
-  DecodeStatus Result = decodeUImmOperand<6>(Inst, UImm6, Address, Decoder);
-  (void)Result;
+  [[maybe_unused]] DecodeStatus Result =
+      decodeUImmOperand<6>(Inst, UImm6, Address, Decoder);
   assert(Result == MCDisassembler::Success && "Invalid immediate");
   return MCDisassembler::Success;
 }
@@ -454,8 +454,8 @@ static DecodeStatus decodeXTHeadMemPair(MCInst &Inst, uint32_t Insn,
   DecodeGPRRegisterClass(Inst, Rd1, Address, Decoder);
   DecodeGPRRegisterClass(Inst, Rd2, Address, Decoder);
   DecodeGPRRegisterClass(Inst, Rs1, Address, Decoder);
-  DecodeStatus Result = decodeUImmOperand<2>(Inst, UImm2, Address, Decoder);
-  (void)Result;
+  [[maybe_unused]] DecodeStatus Result =
+      decodeUImmOperand<2>(Inst, UImm2, Address, Decoder);
   assert(Result == MCDisassembler::Success && "Invalid immediate");
 
   // Disassemble the final operand which is implicit.

llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp

@@ -186,9 +186,8 @@ void RISCVAsmBackend::relaxInstruction(MCInst &Inst,
   case RISCV::C_BNEZ:
   case RISCV::C_J:
   case RISCV::C_JAL: {
-    bool Success = RISCVRVC::uncompress(Res, Inst, STI);
+    [[maybe_unused]] bool Success = RISCVRVC::uncompress(Res, Inst, STI);
     assert(Success && "Can't uncompress instruction");
-    (void)Success;
     break;
   }
   case RISCV::BEQ:
@@ -218,9 +217,9 @@ bool RISCVAsmBackend::relaxDwarfLineAddr(MCDwarfLineAddrFragment &DF,
   size_t OldSize = Data.size();
 
   int64_t Value;
-  bool IsAbsolute = AddrDelta.evaluateKnownAbsolute(Value, Layout);
+  [[maybe_unused]] bool IsAbsolute =
+      AddrDelta.evaluateKnownAbsolute(Value, Layout);
   assert(IsAbsolute && "CFA with invalid expression");
-  (void)IsAbsolute;
 
   Data.clear();
   Fixups.clear();
@@ -283,9 +282,9 @@ bool RISCVAsmBackend::relaxDwarfCFA(MCDwarfCallFrameFragment &DF,
   int64_t Value;
   if (AddrDelta.evaluateAsAbsolute(Value, Layout.getAssembler()))
     return false;
-  bool IsAbsolute = AddrDelta.evaluateKnownAbsolute(Value, Layout);
+  [[maybe_unused]] bool IsAbsolute =
+      AddrDelta.evaluateKnownAbsolute(Value, Layout);
   assert(IsAbsolute && "CFA with invalid expression");
-  (void)IsAbsolute;
 
   Data.clear();
   Fixups.clear();

llvm/lib/Target/RISCV/RISCVFoldMasks.cpp

@@ -146,7 +146,8 @@ bool RISCVFoldMasks::convertToUnmasked(MachineInstr &MI,
   // everything else.  See the comment on RISCVMaskedPseudo for details.
   const unsigned Opc = I->UnmaskedPseudo;
   const MCInstrDesc &MCID = TII->get(Opc);
-  const bool HasPolicyOp = RISCVII::hasVecPolicyOp(MCID.TSFlags);
+  [[maybe_unused]] const bool HasPolicyOp =
+      RISCVII::hasVecPolicyOp(MCID.TSFlags);
   const bool HasPassthru = RISCVII::isFirstDefTiedToFirstUse(MCID);
 #ifndef NDEBUG
   const MCInstrDesc &MaskedMCID = TII->get(MI.getOpcode());

llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp

@@ -2081,10 +2081,10 @@ void RISCVDAGToDAGISel::Select(SDNode *Node) {
       break;
 
     RISCVII::VLMUL SubVecLMUL = RISCVTargetLowering::getLMUL(SubVecContainerVT);
-    bool IsSubVecPartReg = SubVecLMUL == RISCVII::VLMUL::LMUL_F2 ||
-                           SubVecLMUL == RISCVII::VLMUL::LMUL_F4 ||
-                           SubVecLMUL == RISCVII::VLMUL::LMUL_F8;
-    (void)IsSubVecPartReg; // Silence unused variable warning without asserts.
+    [[maybe_unused]] bool IsSubVecPartReg =
+        SubVecLMUL == RISCVII::VLMUL::LMUL_F2 ||
+        SubVecLMUL == RISCVII::VLMUL::LMUL_F4 ||
+        SubVecLMUL == RISCVII::VLMUL::LMUL_F8;
     assert((!IsSubVecPartReg || V.isUndef()) &&
            "Expecting lowering to have created legal INSERT_SUBVECTORs when "
            "the subvector is smaller than a full-sized register");
@@ -2263,9 +2263,8 @@ bool RISCVDAGToDAGISel::SelectInlineAsmMemoryOperand(
   case InlineAsm::ConstraintCode::o:
   case InlineAsm::ConstraintCode::m: {
     SDValue Op0, Op1;
-    bool Found = SelectAddrRegImm(Op, Op0, Op1);
+    [[maybe_unused]] bool Found = SelectAddrRegImm(Op, Op0, Op1);
     assert(Found && "SelectAddrRegImm should always succeed");
-    (void)Found;
     OutOps.push_back(Op0);
     OutOps.push_back(Op1);
     return false;

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -8512,12 +8512,12 @@ static SDValue lowerGetVectorLength(SDNode *N, SelectionDAG &DAG,
   // Determine the VF that corresponds to LMUL 1 for ElementWidth.
   unsigned LMul1VF = RISCV::RVVBitsPerBlock / ElementWidth;
   // We don't support VF==1 with ELEN==32.
-  unsigned MinVF = RISCV::RVVBitsPerBlock / Subtarget.getELen();
+  [[maybe_unused]] unsigned MinVF =
+      RISCV::RVVBitsPerBlock / Subtarget.getELen();
 
-  unsigned VF = N->getConstantOperandVal(2);
+  [[maybe_unused]] unsigned VF = N->getConstantOperandVal(2);
   assert(VF >= MinVF && VF <= (LMul1VF * 8) && isPowerOf2_32(VF) &&
          "Unexpected VF");
-  (void)MinVF;
 
   bool Fractional = VF < LMul1VF;
   unsigned LMulVal = Fractional ? LMul1VF / VF : VF / LMul1VF;
@@ -11227,7 +11227,7 @@ SDValue RISCVTargetLowering::lowerMaskedGather(SDValue Op,
   SDValue Chain = MemSD->getChain();
   SDValue BasePtr = MemSD->getBasePtr();
 
-  ISD::LoadExtType LoadExtType;
+  [[maybe_unused]] ISD::LoadExtType LoadExtType;
   SDValue Index, Mask, PassThru, VL;
 
   if (auto *VPGN = dyn_cast<VPGatherSDNode>(Op.getNode())) {
@@ -11255,7 +11255,6 @@ SDValue RISCVTargetLowering::lowerMaskedGather(SDValue Op,
   // Targets have to explicitly opt-in for extending vector loads.
   assert(LoadExtType == ISD::NON_EXTLOAD &&
          "Unexpected extending MGATHER/VP_GATHER");
-  (void)LoadExtType;
 
   // If the mask is known to be all ones, optimize to an unmasked intrinsic;
   // the selection of the masked intrinsics doesn't do this for us.
@@ -11325,7 +11324,7 @@ SDValue RISCVTargetLowering::lowerMaskedScatter(SDValue Op,
   SDValue Chain = MemSD->getChain();
   SDValue BasePtr = MemSD->getBasePtr();
 
-  bool IsTruncatingStore = false;
+  [[maybe_unused]] bool IsTruncatingStore = false;
   SDValue Index, Mask, Val, VL;
 
   if (auto *VPSN = dyn_cast<VPScatterSDNode>(Op.getNode())) {
@@ -11354,7 +11353,6 @@ SDValue RISCVTargetLowering::lowerMaskedScatter(SDValue Op,
   // Targets have to explicitly opt-in for extending vector loads and
   // truncating vector stores.
   assert(!IsTruncatingStore && "Unexpected truncating MSCATTER/VP_SCATTER");
-  (void)IsTruncatingStore;
 
   // If the mask is known to be all ones, optimize to an unmasked intrinsic;
   // the selection of the masked intrinsics doesn't do this for us.

llvm/lib/Target/RISCV/RISCVInstrInfo.cpp

@@ -1172,7 +1172,6 @@ bool RISCVInstrInfo::optimizeCondBranch(MachineInstr &MI) const {
   SmallVector<MachineOperand, 3> Cond;
   if (analyzeBranch(*MBB, TBB, FBB, Cond, /*AllowModify=*/false))
     return false;
-  (void)FBB;
 
   RISCVCC::CondCode CC = static_cast<RISCVCC::CondCode>(Cond[0].getImm());
   assert(CC != RISCVCC::COND_INVALID);