diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp index c113e4d3166..53015d25842 100644 --- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp +++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp @@ -207,6 +207,7 @@ TargetTransformInfo::UnrollingPreferences llvm::gatherUnrollingPreferences( if (OptForSize) { UP.Threshold = UP.OptSizeThreshold; UP.PartialThreshold = UP.PartialOptSizeThreshold; + UP.MaxPercentThresholdBoost = 100; } // Apply any user values specified by cl::opt @@ -993,6 +994,7 @@ static LoopUnrollResult tryToUnrollLoop( if (OnlyWhenForced && !(TM & TM_Enable)) return LoopUnrollResult::Unmodified; + bool OptForSize = L->getHeader()->getParent()->hasOptSize(); unsigned NumInlineCandidates; bool NotDuplicatable; bool Convergent; @@ -1000,8 +1002,11 @@ static LoopUnrollResult tryToUnrollLoop( L, SE, TTI, BFI, PSI, OptLevel, ProvidedThreshold, ProvidedCount, ProvidedAllowPartial, ProvidedRuntime, ProvidedUpperBound, ProvidedAllowPeeling); - // Exit early if unrolling is disabled. - if (UP.Threshold == 0 && (!UP.Partial || UP.PartialThreshold == 0)) + + // Exit early if unrolling is disabled. For OptForSize, we pick the loop size + // as threshold later on. + if (UP.Threshold == 0 && (!UP.Partial || UP.PartialThreshold == 0) && + !OptForSize) return LoopUnrollResult::Unmodified; SmallPtrSet<const Value *, 32> EphValues; @@ -1016,6 +1021,12 @@ static LoopUnrollResult tryToUnrollLoop( << " instructions.\n"); return LoopUnrollResult::Unmodified; } + + // When optimizing for size, use LoopSize as threshold, to (fully) unroll + // loops, if it does not increase code size. + if (OptForSize) + UP.Threshold = std::max(UP.Threshold, LoopSize); + if (NumInlineCandidates != 0) { LLVM_DEBUG(dbgs() << " Not unrolling loop with inlinable calls.\n"); return LoopUnrollResult::Unmodified; |
