[PATCH] D113577: [SCEV] Support rewriting ZExt expressions with loop guard info.

[Florian Hahn via Phabricator via llvm-commits]

fhahn updated this revision to Diff 386778.
fhahn added a comment.

Updated the code to also apply information collected to other expressions in the mas. This ensures we include information about sub-expressions when applying larger expressions. I added tests that show cases where we would otherwise miss information ( 5dfe60d171d7 <https://reviews.llvm.org/rG5dfe60d171d7f7ebb33c53170cc4182dba22a7b4>) and rebased on top of that.

I also restricted info collection to LHS that are either SCEVUnknown or SCEVZeroExtendExpr for now.

Compile-time wise this shows a very small increase on average: http://llvm-compile-time-tracker.com/compare.php?from=b57c22ade8673d68088f5638a1050e3f3c1f163d&to=5792b893889fbfd459b9ec062dedea6c130b9786&stat=instructions

NewPM-O3: +0.02%
NewPM-ReleaseThinLTO: +0.02%
NewPM-ReleaseLTO-g: +0.04%


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D113577/new/

https://reviews.llvm.org/D113577

Files:
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info-rewrite-expressions.ll

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