Add output alias to fusion

src/include/migraph/operators.hpp

@@ -613,6 +613,7 @@ struct identity
     {
         return {std::move(output_shape), std::move(args.at(0).data)};
     }
+    int output_alias(const std::vector<shape>&) const { return 0; }
 };
 
 struct abs : unary

src/targets/gpu/fuse_ops.cpp

@@ -155,6 +155,7 @@ struct hip_triadd
         device::add(ctx.get_stream().get(), args.at(3), args.at(0), args.at(1), args.at(2));
         return args.at(3);
     }
+    int output_alias(const std::vector<shape>& shapes) const { return shapes.size() - 1; }
 };
 
 struct hip_triadd_relu
@@ -170,6 +171,7 @@ struct hip_triadd_relu
         device::add_relu(ctx.get_stream().get(), args.at(3), args.at(0), args.at(1), args.at(2));
         return args.at(3);
     }
+    int output_alias(const std::vector<shape>& shapes) const { return shapes.size() - 1; }
 };
 
 struct hip_add_relu
@@ -185,6 +187,7 @@ struct hip_add_relu
         device::add_relu(ctx.get_stream().get(), args.at(2), args.at(0), args.at(1));
         return args.at(2);
     }
+    int output_alias(const std::vector<shape>& shapes) const { return shapes.size() - 1; }
 };
 
 struct find_add_relu
@@ -271,6 +274,7 @@ struct miopen_conv_bias
         f.compile(ctx);
         return f.get_workspace(ctx);
     }
+    int output_alias(const std::vector<shape>& shapes) const { return shapes.size() - 1; }
 };
 
 struct miopen_conv_bias_relu
@@ -314,6 +318,7 @@ struct miopen_conv_bias_relu
         f.compile(ctx);
         return f.get_workspace(ctx);
     }
+    int output_alias(const std::vector<shape>& shapes) const { return shapes.size() - 1; }
 };
 
 template <class... Ms>