[llvm] [llvm-exegesis] Add AArch64 operand initializers, SetRegTo (PR #169912)

[Simon Wallis via llvm-commits]

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@@ -1507,6 +1590,7 @@ let OperandNamespace = "AArch64", OperandType = "OPERAND_IMPLICIT_IMM_0",
   defm VectorIndex032b : VectorIndex<i32, VectorIndex0Operand,
                                      [{ return ((uint32_t)Imm) == 0; }]>;
 }
+let OperandType = "OPERAND_IMMEDIATE" in {
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simonwallis2 wrote:

I considered indenting the clauses inside the let.
An arguments against is that this change is clearer without it.

https://github.com/llvm/llvm-project/pull/169912