Porting r50563 from Tak to mainline.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50564 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopIndexSplit.cpp b/lib/Transforms/Scalar/LoopIndexSplit.cpp
index da6f076..a6bd9ff 100644
--- a/lib/Transforms/Scalar/LoopIndexSplit.cpp
+++ b/lib/Transforms/Scalar/LoopIndexSplit.cpp
@@ -1124,6 +1124,11 @@
BasicBlock *Succ0 = SplitTerminator->getSuccessor(0);
BasicBlock *Succ1 = SplitTerminator->getSuccessor(1);
+ // If split block does not dominate the latch then this is not a diamond.
+ // Such loop may not benefit from index split.
+ if (!DT->dominates(SplitCondBlock, Latch))
+ return false;
+
// Finally this split condition is safe only if merge point for
// split condition branch is loop latch. This check along with previous
// check, to ensure that exit condition is in either loop latch or header,