diff --git a/llvm/lib/CodeGen/GlobalISel/Combiner.cpp b/llvm/lib/CodeGen/GlobalISel/Combiner.cpp
--- a/llvm/lib/CodeGen/GlobalISel/Combiner.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/Combiner.cpp
@@ -12,6 +12,7 @@
 
 #include "llvm/CodeGen/GlobalISel/Combiner.h"
 #include "llvm/ADT/PostOrderIterator.h"
+#include "llvm/ADT/SetVector.h"
 #include "llvm/CodeGen/GlobalISel/CSEInfo.h"
 #include "llvm/CodeGen/GlobalISel/CSEMIRBuilder.h"
 #include "llvm/CodeGen/GlobalISel/CombinerInfo.h"
@@ -52,7 +53,9 @@
   WorkListTy &WorkList;
   /// The instructions that have been created but we want to report once they
   /// have their operands. This is only maintained if debug output is requested.
-  SmallPtrSet<const MachineInstr *, 4> CreatedInstrs;
+#ifndef NDEBUG
+  SetVector<const MachineInstr *> CreatedInstrs;
+#endif
 
 public:
   WorkListMaintainer(WorkListTy &WorkList) : WorkList(WorkList) {}