diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 08005c198298..6d5a68214e7c 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1099,7 +1099,7 @@ bool SimplifyCFGOpt::FoldValueComparisonIntoPredecessors(Instruction *TI,
       ++NumFoldValueComparisonIntoPredecessors;
   });
 
-  SmallVector<BasicBlock *, 16> Preds(predecessors(BB));
+  SmallSetVector<BasicBlock *, 16> Preds(pred_begin(BB), pred_end(BB));
   while (!Preds.empty()) {
     BasicBlock *Pred = Preds.pop_back_val();
 
@@ -1260,6 +1260,7 @@ bool SimplifyCFGOpt::FoldValueComparisonIntoPredecessors(Instruction *TI,
       // Okay, at this point, we know which new successor Pred will get.  Make
       // sure we update the number of entries in the PHI nodes for these
       // successors.
+      assert(!NewSuccessors.empty() && "Should be adding some new successors.");
       for (const std::pair<BasicBlock *, int /*Num*/> &NewSuccessor :
            NewSuccessors) {
         for (auto I : seq(0, NewSuccessor.second)) {