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[SCEV] Handle uge/ugt predicates in applyLoopGuards()
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Authored by nikic on Apr 23 2021, 1:12 PM.

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Summary

These can be handled the same way as ule/ult, just using umax instead of umin. This is useful in cases where the umax prevents the upper bound from overflowing.

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Event Timeline

nikic created this revision.Apr 23 2021, 1:12 PM
nikic requested review of this revision.Apr 23 2021, 1:12 PM
Herald added a project: Restricted Project. · View Herald TranscriptApr 23 2021, 1:12 PM
nikic updated this revision to Diff 340308.Apr 24 2021, 12:49 PM

Rebase over some implementation cleanup.

fhahn accepted this revision.Apr 27 2021, 3:33 AM

LGTM, thanks!

Would it be possible to have a test which requires multiple re-writes, by limiting the IV in both directions?

llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll
600

IMO it would slightly increase the readability of the test here if we would use the uge predicate, as in the test name :)

This revision is now accepted and ready to land.Apr 27 2021, 3:33 AM
nikic updated this revision to Diff 340971.Apr 27 2021, 1:37 PM

Rebase over added/improved tests.

nikic marked an inline comment as done.Apr 27 2021, 1:40 PM
nikic added inline comments.
llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll
600

Yeah, that makes a lot more sense :) I just picked picked the order from the original test case...

This revision was landed with ongoing or failed builds.Apr 27 2021, 1:41 PM
This revision was automatically updated to reflect the committed changes.
nikic marked an inline comment as done.