CorrelatedPropagation: BasicBlock::removePredecessor can simplify PHI nodes. If the it's the condition of a SwitchInst, reload it.

Fixes PR13972.

llvm-svn: 164818

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
index 9b0aadb0b5b..3ec6f3dcc31 100644
--- a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
+++ b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
@@ -235,6 +235,11 @@ bool CorrelatedValuePropagation::processSwitch(SwitchInst *SI) {
       // This case never fires - remove it.
       CI.getCaseSuccessor()->removePredecessor(BB);
       SI->removeCase(CI); // Does not invalidate the iterator.
+
+      // The condition can be modified by removePredecessor's PHI simplification
+      // logic.
+      Cond = SI->getCondition();
+
       ++NumDeadCases;
       Changed = true;
     } else if (State == LazyValueInfo::True) {