LSR should avoid redundant edge splitting.
This handles the case in which LSR rewrites an IV user that is a phi and
splits critical edges originating from a switch.
Fixes <rdar://problem/6453893> LSR is not splitting edges "nicely"
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141059 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 7b1a340..4b6c55e 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -3677,7 +3677,9 @@
// Split the critical edge.
BasicBlock *NewBB = 0;
if (!Parent->isLandingPad()) {
- NewBB = SplitCriticalEdge(BB, Parent, P);
+ NewBB = SplitCriticalEdge(BB, Parent, P,
+ /*MergeIdenticalEdges=*/true,
+ /*DontDeleteUselessPhis=*/true);
} else {
SmallVector<BasicBlock*, 2> NewBBs;
SplitLandingPadPredecessors(Parent, BB, "", "", P, NewBBs);