diff --git a/polly/lib/Analysis/ScopBuilder.cpp b/polly/lib/Analysis/ScopBuilder.cpp
index c0babb85f5c4..67a4c4345580 100644
--- a/polly/lib/Analysis/ScopBuilder.cpp
+++ b/polly/lib/Analysis/ScopBuilder.cpp
@@ -689,7 +689,7 @@ isl::set ScopBuilder::getPredecessorDomainConstraints(BasicBlock *BB,
 
   // Set of regions of which the entry block domain has been propagated to BB.
   // all predecessors inside any of the regions can be skipped.
-  SmallSet<Region *, 8> PropagatedRegions;
+  SmallPtrSet<Region *, 8> PropagatedRegions;
 
   for (auto *PredBB : predecessors(BB)) {
     // Skip backedges.