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

[Lakshay Kumar via llvm-commits]

lakshayk-nv wrote:

The added test case in this PR (`tools/llvm-exegesis/AArch64/error-resolution.s`) is has a minor problem. 
The negative testcases checking non-existence of error should not check for opcode.

i.e. `# UMOVvi16_idx0_latency-NOT: Not all operands were initialized by the snippet generator for UMOVvi16_idx0 opcode.` should rather be something like
`# UMOVvi16_idx0_latency-NOT: \w+: Not all operands were initialized by the snippet generator for \w+ opcode\.`

I will be pushing changes asap, Apologies.

[Why it fails (only sometimes)]
Exegesis in latency mode require the generated assembly to be chained to ensure serial execution,
For this exegesis add an additional consumer instruction for some instruction, which is chosen via a random seed.
Thus, it randomly fails whenever there is secondary consumer instruction (which is unsupported/throws error) added in generated assembly.

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