From 74418185601af7ada9e07c6acdb237ec35b4ca43 Mon Sep 17 00:00:00 2001 From: Florian Hahn Date: Mon, 23 Apr 2018 21:38:19 +0000 Subject: [PATCH] [LoopInterchange] Do not change LI for BBs in child loops. If a loop with child loops becomes our new inner loop after interchanging, we only need to update LoopInfo for the blocks defined in the old outer loop. BBs in child loops will stay there. Reviewers: efriedma, karthikthecool, mcrosier Reviewed By: efriedma Differential Revision: https://reviews.llvm.org/D45970 llvm-svn: 330653 --- llvm/lib/Transforms/Scalar/LoopInterchange.cpp | 3 +++ 1 file changed, 3 insertions(+) diff --git a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp index cab6acc..a641afe 100644 --- a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp +++ b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp @@ -1220,6 +1220,9 @@ void LoopInterchangeTransform::restructureLoops( BasicBlock *OuterHeader = NewOuter->getHeader(); BasicBlock *OuterLatch = NewOuter->getLoopLatch(); for (BasicBlock *BB : OrigInnerBBs) { + // Nothing will change for BBs in child loops. + if (LI->getLoopFor(BB) != NewOuter) + continue; // Remove the new outer loop header and latch from the new inner loop. if (BB == OuterHeader || BB == OuterLatch) NewInner->removeBlockFromLoop(BB); -- 2.7.4