[RISCV] Add OperandType to frmarg and rtzarg. (#114142)

Teach RISCVInstrInfo::verifyInstruction to validate them.

This is partially extracted from #89047, but that did not include the
verification.

Author: topperc

llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h

@@ -330,7 +330,12 @@ enum OperandType : unsigned {
   OPERAND_RVKRNUM_1_10,
   OPERAND_RVKRNUM_2_14,
   OPERAND_SPIMM,
-  OPERAND_LAST_RISCV_IMM = OPERAND_SPIMM,
+  // Operand is a 3-bit rounding mode, '111' indicates FRM register.
+  // Represents 'frm' argument passing to floating-point operations.
+  OPERAND_FRMARG,
+  // Operand is a 3-bit rounding mode where only RTZ is valid.
+  OPERAND_RTZARG,
+  OPERAND_LAST_RISCV_IMM = OPERAND_RTZARG,
   // Operand is either a register or uimm5, this is used by V extension pseudo
   // instructions to represent a value that be passed as AVL to either vsetvli
   // or vsetivli.

llvm/lib/Target/RISCV/RISCVInstrInfo.cpp

@@ -2536,6 +2536,12 @@ bool RISCVInstrInfo::verifyInstruction(const MachineInstr &MI,
         case RISCVOp::OPERAND_SPIMM:
           Ok = (Imm & 0xf) == 0;
           break;
+        case RISCVOp::OPERAND_FRMARG:
+          Ok = RISCVFPRndMode::isValidRoundingMode(Imm);
+          break;
+        case RISCVOp::OPERAND_RTZARG:
+          Ok = Imm == RISCVFPRndMode::RTZ;
+          break;
         }
         if (!Ok) {
           ErrInfo = "Invalid immediate";

llvm/lib/Target/RISCV/RISCVInstrInfoF.td

@@ -134,6 +134,8 @@ def frmarg : Operand<XLenVT> {
   let ParserMatchClass = FRMArg;
   let PrintMethod = "printFRMArg";
   let DecoderMethod = "decodeFRMArg";
+  let OperandType = "OPERAND_FRMARG";
+  let OperandNamespace = "RISCVOp";
 }
 
 // Variants of the rounding mode operand that default to 'rne'. This is used
@@ -154,6 +156,8 @@ def frmarglegacy : Operand<XLenVT> {
   let ParserMatchClass = FRMArgLegacy;
   let PrintMethod = "printFRMArgLegacy";
   let DecoderMethod = "decodeFRMArg";
+  let OperandType = "OPERAND_FRMARG";
+  let OperandNamespace = "RISCVOp";
 }
 
 //===----------------------------------------------------------------------===//

llvm/lib/Target/RISCV/RISCVInstrInfoZfa.td

@@ -48,6 +48,8 @@ def rtzarg : Operand<XLenVT> {
   let ParserMatchClass = RTZArg;
   let PrintMethod = "printFRMArg";
   let DecoderMethod = "decodeRTZArg";
+  let OperandType = "OPERAND_RTZARG";
+  let OperandNamespace = "RISCVOp";
 }
 
 //===----------------------------------------------------------------------===//