Don't merge in tail block of a diamond if it has more than one predecessors after if-conversion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37353 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp
index 8e7b0fe..a57fba9 100644
--- a/lib/CodeGen/IfConversion.cpp
+++ b/lib/CodeGen/IfConversion.cpp
@@ -555,9 +555,11 @@
} else
InsertUncondBranch(BBI.BB, CvtBBI->BB, TII);
- // If the if-converted block fallthrough into the tail block, then
+ // If the if-converted block fallthrough or unconditionally branch into the
+ // tail block, and the tail block does not have other predecessors, then
// fold the tail block in as well.
- if (BBI.TailBB && CvtBBI->BB->succ_size() == 1) {
+ if (BBI.TailBB &&
+ BBI.TailBB->succ_size() == 1 && CvtBBI->BB->succ_size() == 1) {
CvtBBI->NonPredSize -= TII->RemoveBranch(*CvtBBI->BB);
BBInfo TailBBI = BBAnalysis[BBI.TailBB->getNumber()];
MergeBlocks(*CvtBBI, TailBBI);