[llvm] Re-apply (#89047):[Exegesis][RISCV] Add RISCV support for llvm-exegesis (PR #120419)

[Pengcheng Wang via llvm-commits]

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@@ -54,12 +54,6 @@ computeAliasingInstructions(const LLVMState &State, const Instruction *Instr,
       continue;
     const Instruction &OtherInstr = State.getIC().getInstr(OtherOpcode);
     const MCInstrDesc &OtherInstrDesc = OtherInstr.Description;
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wangpc-pp wrote:

This line should be removed, the variable is unused.

https://github.com/llvm/llvm-project/pull/120419