From 66c8ba5a50ead4fcf4c64c466fbb64cb95d15711 Mon Sep 17 00:00:00 2001 From: Ikhlas Ajbar Date: Fri, 30 Mar 2018 03:05:34 +0000 Subject: peel loops with runtime small trip counts For Hexagon, peeling loops with small runtime trip count is beneficial for our benchmarks. We set PeelCount in HexagonTargetInfo.cpp and we use PeelCount set by the target for computing the desired peel count. Differential Revision: https://reviews.llvm.org/D44880 llvm-svn: 328854 --- llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'llvm/lib/Transforms/Utils') diff --git a/llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp b/llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp index 5f465f328b0..cfbecd59af3 100644 --- a/llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp +++ b/llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp @@ -221,6 +221,9 @@ void llvm::computePeelCount(Loop *L, unsigned LoopSize, TargetTransformInfo::UnrollingPreferences &UP, unsigned &TripCount, ScalarEvolution &SE) { assert(LoopSize > 0 && "Zero loop size is not allowed!"); + // Save the UP.PeelCount value set by the target in + // TTI.getUnrollingPreferences or by the flag -unroll-peel-count. + unsigned TargetPeelCount = UP.PeelCount; UP.PeelCount = 0; if (!canPeel(L)) return; @@ -240,7 +243,9 @@ void llvm::computePeelCount(Loop *L, unsigned LoopSize, SmallDenseMap IterationsToInvariance; // Now go through all Phis to calculate their the number of iterations they // need to become invariants. - unsigned DesiredPeelCount = 0; + // Start the max computation with the UP.PeelCount value set by the target + // in TTI.getUnrollingPreferences or by the flag -unroll-peel-count. + unsigned DesiredPeelCount = TargetPeelCount; BasicBlock *BackEdge = L->getLoopLatch(); assert(BackEdge && "Loop is not in simplified form?"); for (auto BI = L->getHeader()->begin(); isa(&*BI); ++BI) { -- cgit v1.2.3