diff --git a/include/mlir-hlo/Dialect/mhlo/IR/infer_fusibility_op_interface.td b/include/mlir-hlo/Dialect/mhlo/IR/infer_fusibility_op_interface.td
index f8e02d4..280c0a1 100644
--- a/include/mlir-hlo/Dialect/mhlo/IR/infer_fusibility_op_interface.td
+++ b/include/mlir-hlo/Dialect/mhlo/IR/infer_fusibility_op_interface.td
@@ -50,7 +50,7 @@ def InferFusibilityOpInterface : OpInterface<"InferFusibilityOpInterface"> {
       /*args=*/(ins),
       /*methodBody=*/[{}],
       /*defaultImplementation=*/[{
-        /// Return whether this op can be fused withh its consumers
+        /// Return whether this op can be fused with its consumers
         return true;
       }]
     >,
@@ -64,21 +64,9 @@ def InferFusibilityOpInterface : OpInterface<"InferFusibilityOpInterface"> {
       /*defaultImplementation=*/[{
         /// Return whether two inputs have the same shape.
         Operation *op = this->getOperation();
-        assert(lhs < op->getNumOperands() && lhs >= 0 &&
-               rhs < op->getNumOperands() && rhs >= 0);
+        assert(lhs >= 0 && rhs >= 0);
         if (lhs == rhs) return true;
-
-        // if both lhs and rhs have static shapes, check them directly
-        Type lhs_ty = op->getOperand(lhs).getType();
-        Type rhs_ty = op->getOperand(rhs).getType();
-        auto lhs_shape_type = lhs_ty.dyn_cast_or_null<RankedTensorType>();
-        auto rhs_shape_type = rhs_ty.dyn_cast_or_null<RankedTensorType>();
-        if (!lhs_shape_type || !lhs_shape_type.hasStaticShape() ||
-            !rhs_shape_type || !rhs_shape_type.hasStaticShape() ||
-            lhs_shape_type.getRank() != rhs_shape_type.getRank()) {
-          return false;
-        }
-        return lhs_shape_type.getShape() == rhs_shape_type.getShape();
+        return inferShapeEquality(op->getOperand(lhs), op->getOperand(rhs));
       }]
     >,
     InterfaceMethod<
@@ -91,21 +79,9 @@ def InferFusibilityOpInterface : OpInterface<"InferFusibilityOpInterface"> {
       /*defaultImplementation=*/[{
         /// Return whether two outputs have the same shape.
         Operation *op = this->getOperation();
-        assert(lhs < op->getNumResults() && lhs >= 0 &&
-               rhs < op->getNumResults() && rhs >= 0);
+        assert(lhs >= 0 && rhs >= 0);
         if (lhs == rhs) return true;
-
-        // if both lhs and rhs have static shapes, check them directly
-        Type lhs_ty = op->getResult(lhs).getType();
-        Type rhs_ty = op->getResult(rhs).getType();
-        auto lhs_shape_type = lhs_ty.dyn_cast_or_null<RankedTensorType>();
-        auto rhs_shape_type = rhs_ty.dyn_cast_or_null<RankedTensorType>();
-        if (!lhs_shape_type || !lhs_shape_type.hasStaticShape() ||
-            !rhs_shape_type || !rhs_shape_type.hasStaticShape() ||
-            lhs_shape_type.getRank() != rhs_shape_type.getRank()) {
-          return false;
-        }
-        return lhs_shape_type.getShape() == rhs_shape_type.getShape();
+        return inferShapeEquality(op->getResult(lhs), op->getResult(rhs));
       }]
     >,
     InterfaceMethod<
@@ -118,20 +94,8 @@ def InferFusibilityOpInterface : OpInterface<"InferFusibilityOpInterface"> {
       /*defaultImplementation=*/[{
         /// Return whether the input and the output have the same shape.
         Operation *op = this->getOperation();
-        assert(input < op->getNumOperands() && input >= 0 &&
-               output < op->getNumResults() && output >= 0);
-
-        // if both input and output have static shapes, check them directly
-        Type input_ty = op->getOperand(input).getType();
-        Type output_ty = op->getResult(output).getType();
-        auto input_shape_type = input_ty.dyn_cast_or_null<RankedTensorType>();
-        auto output_shape_type = output_ty.dyn_cast_or_null<RankedTensorType>();
-        if (!input_shape_type || !input_shape_type.hasStaticShape() ||
-            !output_shape_type || !output_shape_type.hasStaticShape() ||
-            input_shape_type.getRank() != output_shape_type.getRank()) {
-          return false;
-        }
-        return input_shape_type.getShape() == output_shape_type.getShape();
+        assert(input >= 0 && output >= 0);
+        return inferShapeEquality(op->getOperand(input), op->getResult(output));
       }]
     >,
     InterfaceMethod<
@@ -156,6 +120,21 @@ def InferFusibilityOpInterface : OpInterface<"InferFusibilityOpInterface"> {
       }]
     >,
   ];
+
+  let extraClassDeclaration = [{
+    // Returns whether the given values have the same static shape.
+    static bool inferShapeEquality(Value first, Value second) {
+      // If both lhs and rhs have static shapes, check them directly.
+      auto first_ty = first.getType().dyn_cast<RankedTensorType>();
+      auto second_ty = second.getType().dyn_cast<RankedTensorType>();
+      if (!first_ty || !first_ty.hasStaticShape() ||
+          !second_ty || !second_ty.hasStaticShape() ||
+          first_ty.getRank() != second_ty.getRank()) {
+        return false;
+      }
+      return first_ty.getShape() == second_ty.getShape();
+    }
+  }];
 }
 
 #endif