[llvm] [llvm-exegesis] [AArch64] Resolving "not all operands are initialized by snippet generator" (PR #142529)

[Lakshay Kumar via llvm-commits]

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@@ -276,6 +276,12 @@ static Error randomizeMCOperand(const LLVMState &State,
     AssignedValue = MCOperand::createReg(randomBit(AllowedRegs));
     break;
   }
+  /// Omit unknown and pc-relative operands to imm value based on the
+  /// instruction
+  case MCOI::OperandType::OPERAND_UNKNOWN:
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lakshayk-nv wrote:

This is helps us to get measurement values for 1000+ opcode. We have sanity checked this by comparing the measurements values reported by exegesis and (latency and inverse-throughput) for them. And there are few opcodes for which omitting immediate with value 0 is incorrect, They are documented in code and this PR (like `UDF`, `SYSLxt)

https://github.com/llvm/llvm-project/pull/142529