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Revert "[PassManager] Run additional LICM before LoopRotate"
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Authored by lebedev.ri on Feb 16 2022, 1:34 PM.

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lebedev.ri created this revision.Feb 16 2022, 1:34 PM

I think someone else also needs to review this, but this looks good to me

But, apparently, some other improvements to other optimizations passes
have also solved the problem, because, as the diff shows, reverting D99249
does not resurface the original problem, since, clearly, the check lines
for the new-pm and -O2/-O3 are not affected.

Do you have any idea what could have caused this? I find it particularly odd that this is solved for the NewPM but not the OldPM (I don't think we added any pipeline divergences recently...)

llvm/test/Other/new-pm-defaults.ll
169–170

A bit confused here: Why does this become O23SZ rather than being dropped entirely?

llvm/test/Transforms/PhaseOrdering/X86/speculation-vs-tbaa.ll
12

Not strictly necessary, but it would be preferable if this test showed an actual optimization impact (as alluded in https://github.com/llvm/llvm-project/issues/53794#issuecomment-1037460605) rather than just the fact that TBAA is preserved (which is best-effort).

lebedev.ri planned changes to this revision.Feb 17 2022, 3:59 AM
lebedev.ri updated this revision to Diff 409576.
lebedev.ri marked 2 inline comments as done.
lebedev.ri edited the summary of this revision. (Show Details)
ormris removed a subscriber: ormris.Feb 17 2022, 1:21 PM
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