diff --git a/mlir/include/mlir/TableGen/CodeGenHelpers.h b/mlir/include/mlir/TableGen/CodeGenHelpers.h
--- a/mlir/include/mlir/TableGen/CodeGenHelpers.h
+++ b/mlir/include/mlir/TableGen/CodeGenHelpers.h
@@ -114,7 +114,7 @@
   ///
   /// Constraints that do not meet the restriction that they can only reference
   /// `$_self`, `$_op`, and `$_builder` are not uniqued.
-  void emitPatternConstraints(const DenseSet<DagLeaf> &constraints);
+  void emitPatternConstraints(const ArrayRef<DagLeaf> constraints);
 
   /// Get the name of the static function used for the given type constraint.
   /// These functions are used for operand and result constraints and have the
@@ -178,7 +178,7 @@
   /// Collect and unique all the constraints used by operations.
   void collectOpConstraints(ArrayRef<llvm::Record *> opDefs);
   /// Collect and unique all pattern constraints.
-  void collectPatternConstraints(const DenseSet<DagLeaf> &constraints);
+  void collectPatternConstraints(ArrayRef<DagLeaf> constraints);
 
   /// The output stream.
   raw_ostream &os;
diff --git a/mlir/tools/mlir-tblgen/CodeGenHelpers.cpp b/mlir/tools/mlir-tblgen/CodeGenHelpers.cpp
--- a/mlir/tools/mlir-tblgen/CodeGenHelpers.cpp
+++ b/mlir/tools/mlir-tblgen/CodeGenHelpers.cpp
@@ -62,7 +62,7 @@
 }
 
 void StaticVerifierFunctionEmitter::emitPatternConstraints(
-    const llvm::DenseSet<DagLeaf> &constraints) {
+    const llvm::ArrayRef<DagLeaf> constraints) {
   collectPatternConstraints(constraints);
   emitPatternConstraints();
 }
@@ -332,7 +332,7 @@
 }
 
 void StaticVerifierFunctionEmitter::collectPatternConstraints(
-    const llvm::DenseSet<DagLeaf> &constraints) {
+    const llvm::ArrayRef<DagLeaf> constraints) {
   for (auto &leaf : constraints) {
     assert(leaf.isOperandMatcher() || leaf.isAttrMatcher());
     collectConstraint(
diff --git a/mlir/tools/mlir-tblgen/RewriterGen.cpp b/mlir/tools/mlir-tblgen/RewriterGen.cpp
--- a/mlir/tools/mlir-tblgen/RewriterGen.cpp
+++ b/mlir/tools/mlir-tblgen/RewriterGen.cpp
@@ -322,7 +322,7 @@
   int staticMatcherCounter = 0;
 
   // The DagLeaf which contains type or attr constraint.
-  DenseSet<DagLeaf> constraints;
+  SetVector<DagLeaf> constraints;
 
   // Static type/attribute verification function emitter.
   StaticVerifierFunctionEmitter staticVerifierEmitter;
@@ -1713,7 +1713,7 @@
 }
 
 void StaticMatcherHelper::populateStaticConstraintFunctions(raw_ostream &os) {
-  staticVerifierEmitter.emitPatternConstraints(constraints);
+  staticVerifierEmitter.emitPatternConstraints(constraints.getArrayRef());
 }
 
 void StaticMatcherHelper::addPattern(Record *record) {