[PATCH] D120230: [SelectOpti][1/4] Setup new select-optimize pass

[Sotiris Apostolakis via Phabricator via llvm-commits]

apostolakis added a subscriber: modimo.
apostolakis added a comment.

In D120230#3374674 <https://reviews.llvm.org/D120230#3374674>, @wenlei wrote:

> Thanks for the patches. We've noticed similar problems as you described in RFC which often leads to way too aggressive cmov (in general and in comparison to gcc). Is the current version of this stack complete and functional? If so, we'd be happy to give it a try to see how it handles the suboptimal cases we spotted.

This stack is complete and functional for x86 instr-PGO. It is not yet tuned for Sample-PGO and there are some Sample-PGO-specific improvements that are yet to be made, most notably leveraging LBR data to capture misprediction rates and incorporating them in the heuristics (as discussed with @modimo in the RFC). So, if you are interested in Sample-PGO it is better to wait for the next patch series that will tailor this pass for that. At that point, we can iterate and refine to make sure that the pass addresses these suboptimal cases and avoids regressions for your workloads.


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