[llvm] [RISCV][MC] Implement MC for Base P extension (PR #123271)

[Craig Topper via llvm-commits]

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+//===-- RISCVInstrInfoP.td - RISC-V 'P' instructions -------*- tablegen -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file describes the RISC-V instructions from the standard 'Base P'
+// Packed SIMD instruction set extension.
+///
+/// This version is still experimental as the 'P' extension hasn't been
+/// ratified yet.
+///
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+// Operand and SDNode transformation definitions.
+//===----------------------------------------------------------------------===//
+
+def simm10 : RISCVSImmLeafOp<10> {
+  let MCOperandPredicate = [{
+    int64_t Imm;
+    if (MCOp.evaluateAsConstantImm(Imm))
+      return isInt<10>(Imm);
+    return MCOp.isBareSymbolRef();
+  }];
+}
+
+//===----------------------------------------------------------------------===//
+// Instruction class templates
+//===----------------------------------------------------------------------===//
+
+let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in
+class RVPUnary<bits<5> funct5, bits<7> wuimm,
+               bits<3> funct3, RISCVOpcode opcode,
+               string opcodestr>
+    : RVInstIBase<funct3, opcode, (outs GPR:$rd), (ins GPR:$rs1),
+                  opcodestr, "$rd, $rs1"> {
+    let Inst{31-27} = funct5;
+    let Inst{26-20} = wuimm;
+}
+
+let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in
+class RVPUnaryImm9<bits<7> funct7, RISCVOpcode opcode,
+                                 string opcodestr, DAGOperand TyRd = GPR>
+  : RVInstIBase<0b010, opcode, (outs TyRd:$rd), (ins simm10:$simm10),
+                opcodestr, "$rd, $simm10"> {
+  bits<10> simm10;
+
+  let Inst{31-25} = funct7;
+  let Inst{24-15} = simm10;
+}
+
+let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in
+class RVPUnaryImm8<bits<8> funct8, RISCVOpcode opcode,
+                                 string opcodestr, DAGOperand TyRd = GPR>
+  : RVInstIBase<0b010, opcode, (outs TyRd:$rd), (ins uimm8:$uimm8),
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topperc wrote:

indent 4 spaces

https://github.com/llvm/llvm-project/pull/123271