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

[Qihan Cai via llvm-commits]

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@@ -149,6 +149,48 @@ class RVPShiftB_ri<bits<3> f, bits<3> funct3, string opcodestr>
   let Inst{22-20} = shamt;
 }
 
+class RVPPairShift_ri<bits<3> f, string opcodestr, Operand ImmType>
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realqhc wrote:

My proposed names are as follows. 
| Input\Output | GPR         | GPRPair         |
|--------------|-------------|-----------------|
| GPR          | RVPShift_ri (existing) | RVPPairShift_ri |
| GPRPair      | RVPShift_pi | RVPPairShift_pi |

Should we find another way for output type here?

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