diff --git a/mlir/include/mlir/Dialect/PDL/IR/PDLOps.td b/mlir/include/mlir/Dialect/PDL/IR/PDLOps.td
--- a/mlir/include/mlir/Dialect/PDL/IR/PDLOps.td
+++ b/mlir/include/mlir/Dialect/PDL/IR/PDLOps.td
@@ -277,7 +277,9 @@
     operations correspond to input operations, or those that already existing
     within the MLIR module. Inside of a `pdl.rewrite`, these operations
     correspond to operations that should be created as part of the replacement
-    sequence.
+    sequence. The `commutative` attribute if present, specifies to the matcher
+    that the operation should be treated as commutative with respect to all its
+    operands.
 
     `pdl.operation`s are composed of a name, and a set of attribute, operand,
     and result type values, that map to what those that would be on a
@@ -365,16 +367,22 @@
     %otherResults = pdl.types
     %op = pdl.operation "foo.op" -> (%result, %otherResults : !pdl.type, !pdl.range<type>)
     ```
+
+    ```mlir
+    // If the operation is commutative:
+    %op = pdl.operation "foo.op" commutative (%operand : !pdl.value) -> (%result : !pdl.type)
+    ```
   }];
 
   let arguments = (ins OptionalAttr<StrAttr>:$name,
+                       OptionalAttr<UnitAttr>:$commutative,
                        Variadic<PDL_InstOrRangeOf<PDL_Value>>:$operands,
                        Variadic<PDL_Attribute>:$attributes,
                        StrArrayAttr:$attributeNames,
                        Variadic<PDL_InstOrRangeOf<PDL_Type>>:$types);
   let results = (outs PDL_Operation:$op);
   let assemblyFormat = [{
-    ($name^)? (`(` $operands^ `:` type($operands) `)`)?
+    ($name^)? (`commutative` $commutative^)? (`(` $operands^ `:` type($operands) `)`)?
     custom<OperationOpAttributes>($attributes, $attributeNames)
     (`->` `(` $types^ `:` type($types) `)`)? attr-dict
   }];
@@ -386,9 +394,10 @@
       CArg<"ValueRange", "llvm::None">:$attrValues,
       CArg<"ValueRange", "llvm::None">:$resultTypes), [{
       auto nameAttr = name ? $_builder.getStringAttr(*name) : StringAttr();
+      auto commutativeAttr = UnitAttr();
       build($_builder, $_state, $_builder.getType<OperationType>(), nameAttr,
-            operandValues, attrValues, $_builder.getStrArrayAttr(attrNames),
-            resultTypes);
+            commutativeAttr, operandValues, attrValues,
+            $_builder.getStrArrayAttr(attrNames), resultTypes);
     }]>,
   ];
   let extraClassDeclaration = [{
diff --git a/mlir/test/Dialect/PDL/ops.mlir b/mlir/test/Dialect/PDL/ops.mlir
--- a/mlir/test/Dialect/PDL/ops.mlir
+++ b/mlir/test/Dialect/PDL/ops.mlir
@@ -157,3 +157,14 @@
     apply_native_rewrite "NativeRewrite"(%attr : !pdl.attribute)
   }
 }
+
+// -----
+
+// Check that the optional attribute for commutative operations is working.
+pdl.pattern @operations : benefit(1) {
+  %type = pdl.type
+  %input0 = pdl.operand
+  %input1 = pdl.operand
+  %root = pdl.operation "foo.op" commutative (%input0, %input1 : !pdl.value, !pdl.value) ->(%type : !pdl.type)
+  pdl.rewrite %root with "rewriter"
+}