[llvm] r330653 - [LoopInterchange] Do not change LI for BBs in child loops.

[Florian Hahn via llvm-commits]

Author: fhahn
Date: Mon Apr 23 14:38:19 2018
New Revision: 330653

URL: http://llvm.org/viewvc/llvm-project?rev=330653&view=rev
Log:
[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

Modified:
    llvm/trunk/lib/Transforms/Scalar/LoopInterchange.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/LoopInterchange.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopInterchange.cpp?rev=330653&r1=330652&r2=330653&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopInterchange.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopInterchange.cpp Mon Apr 23 14:38:19 2018
@@ -1220,6 +1220,9 @@ void LoopInterchangeTransform::restructu
   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);