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| author | Max Kazantsev <max.kazantsev@azul.com> | 2017-12-06 12:44:56 +0000 |
|---|---|---|
| committer | Max Kazantsev <max.kazantsev@azul.com> | 2017-12-06 12:44:56 +0000 |
| commit | d4f5987c5895ee36fbac586f1f9be428a54f7099 (patch) | |
| tree | c26a3fdaab7790019f6d1599de919362729e4631 /llvm/lib | |
| parent | 515f42cbaab3597d17d0e4bc16c05b4837c727a8 (diff) | |
| download | bcm5719-llvm-d4f5987c5895ee36fbac586f1f9be428a54f7099.tar.gz bcm5719-llvm-d4f5987c5895ee36fbac586f1f9be428a54f7099.zip | |
[SCEV][NFC] Check NoWrap flags before lexicographical comparison of SCEVs
Lexicographical comparison of SCEV trees is potentially expensive for big
expression trees. We can define ordering between them for AddRecs and
N-ary operations by SCEV NoWrap flags to make non-equality check
cheaper.
This change does not prevent grouping eqivalent SCEVs together and is
not supposed to have any meaningful impact on behavior of any transforms.
Reviewed By: sanjoy
Differential Revision: https://reviews.llvm.org/D40645
llvm-svn: 319889
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index 48c08b3e10f..9bc8f2dc83d 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -694,6 +694,10 @@ static int CompareSCEVComplexity( if (LNumOps != RNumOps) return (int)LNumOps - (int)RNumOps; + // Compare NoWrap flags. + if (LA->getNoWrapFlags() != RA->getNoWrapFlags()) + return (int)LA->getNoWrapFlags() - (int)RA->getNoWrapFlags(); + // Lexicographically compare. for (unsigned i = 0; i != LNumOps; ++i) { int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, @@ -718,6 +722,10 @@ static int CompareSCEVComplexity( if (LNumOps != RNumOps) return (int)LNumOps - (int)RNumOps; + // Compare NoWrap flags. + if (LC->getNoWrapFlags() != RC->getNoWrapFlags()) + return (int)LC->getNoWrapFlags() - (int)RC->getNoWrapFlags(); + for (unsigned i = 0; i != LNumOps; ++i) { int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, LC->getOperand(i), RC->getOperand(i), DT, |
