diff --git a/mlir/include/mlir/Transforms/Passes.h b/mlir/include/mlir/Transforms/Passes.h
--- a/mlir/include/mlir/Transforms/Passes.h
+++ b/mlir/include/mlir/Transforms/Passes.h
@@ -60,7 +60,7 @@
 
 /// Creates a pass which prints the list of ops and the number of occurrences in
 /// the module.
-std::unique_ptr<Pass> createPrintOpStatsPass();
+std::unique_ptr<Pass> createPrintOpStatsPass(raw_ostream &os = llvm::errs());
 
 /// Creates a pass which inlines calls and callable operations as defined by
 /// the CallGraph.
diff --git a/mlir/lib/Transforms/OpStats.cpp b/mlir/lib/Transforms/OpStats.cpp
--- a/mlir/lib/Transforms/OpStats.cpp
+++ b/mlir/lib/Transforms/OpStats.cpp
@@ -19,7 +19,7 @@
 
 namespace {
 struct PrintOpStatsPass : public PrintOpStatsBase<PrintOpStatsPass> {
-  explicit PrintOpStatsPass(raw_ostream &os = llvm::errs()) : os(os) {}
+  explicit PrintOpStatsPass(raw_ostream &os) : os(os) {}
 
   // Prints the resultant operation statistics post iterating over the module.
   void runOnOperation() override;
@@ -80,6 +80,6 @@
   }
 }
 
-std::unique_ptr<Pass> mlir::createPrintOpStatsPass() {
-  return std::make_unique<PrintOpStatsPass>();
+std::unique_ptr<Pass> mlir::createPrintOpStatsPass(raw_ostream &os) {
+  return std::make_unique<PrintOpStatsPass>(os);
 }