[llvm] [RISC-V] Add P-ext MC Support for More Pair Operations (PR #154088)

[Craig Topper via llvm-commits]

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@@ -98,6 +98,24 @@ class PLUI_i<bits<7> funct7, string opcodestr>
   let Inst{23-15} = imm10{9-1};
 }
 
+// Common base for widening binary ops
+class RVPWideningBase<bits<2> w, bit arith_shift, string opcodestr>
+  : RVInst<(outs GPRPairRV32:$rd), (ins GPR:$rs1, GPR:$rs2), opcodestr,
+           "$rd, $rs1, $rs2", [], InstFormatOther> {
+  bits<5> rs2;
+  bits<5> rs1;
+  bits<5> rd;
+
+  let Inst{31}    = 0b0;
+  let Inst{26-25} = w;
+  let Inst{24-20} = rs2;
+  let Inst{19-15} = rs1;
+  let Inst{14-12} = 0b010;
+  let Inst{11-8}  = rd{4-1};
+  let Inst{7}     = arith_shift;
+  let Inst{6-0}   = OPC_OP_32.Value;
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topperc wrote:

This is the wrong opcode. It should be OP_IMM_32 as specified on page 3 of the encoding spec.

https://github.com/llvm/llvm-project/pull/154088