[PATCH] D124089: [RISCV] Add a test showing incorrect VSETVLI insertion

[Fraser Cormack via Phabricator via llvm-commits]

frasercrmck added a comment.

It appears as if this is what D119518 <https://reviews.llvm.org/D119518> is trying to achieve, but since we're not inserting any VSETVLIs in `bb.1`, `CurInfo` isn't valid and so we skip the insertion. I tried making it insert vsetvlis if CurInfo is invalid (out of safety) but that's perhaps too pessimistic, as then it inserts a VSETVLI at the end of `bb.2` as well. We don't have the scope during phase 3 to work out that the emergency VSETVLI inserted at the end of `bb.1` would cover that.

Unless we do something naive like that then try and remove them later? We're obviously at the limits of what this pass can do so I don't know if that's just another short-term solution.


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https://reviews.llvm.org/D124089