[ET][Portable] Fix & cleanup op gelu

kernels/portable/cpu/op_gelu.cpp

@@ -9,9 +9,9 @@
 #include <cmath>
 
 #include <executorch/kernels/portable/cpu/math_constants.h>
+#include <executorch/kernels/portable/cpu/util/activation_ops_util.h>
 #include <executorch/kernels/portable/cpu/util/functional_util.h>
 #include <executorch/runtime/kernel/kernel_includes.h>
-#include <executorch/runtime/platform/assert.h>
 
 namespace torch {
 namespace executor {
@@ -28,10 +28,11 @@ Tensor& gelu_out(
     Tensor& out) {
   (void)ctx;
 
-  Error err = resize_tensor(out, in.sizes());
-  ET_CHECK_MSG(err == Error::Ok, "Could not resize output");
+  ET_KERNEL_CHECK(
+      ctx, check_gelu_args(in, approximate, out), InvalidArgument, out);
 
-  ET_CHECK_SAME_SHAPE_AND_DTYPE2(in, out);
+  ET_KERNEL_CHECK(
+      ctx, resize_tensor(out, in.sizes()) == Error::Ok, InvalidArgument, out);
 
   ET_SWITCH_FLOAT_TYPES(in.scalar_type(), ctx, "gelu", CTYPE, [&]() {
     if (approximate == "tanh") {

kernels/portable/cpu/targets.bzl

@@ -345,6 +345,7 @@ _ATEN_OPS = (
         name = "op_gelu",
         deps = [
             ":math_constants",
+            "//executorch/kernels/portable/cpu/util:activation_ops_util",
             "//executorch/kernels/portable/cpu/util:functional_util",
         ],
     ),

kernels/portable/cpu/util/activation_ops_util.cpp

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <cstring>
+
+#include <executorch/kernels/portable/cpu/util/activation_ops_util.h>
+
+namespace torch {
+namespace executor {
+
+bool check_gelu_args(const Tensor& in, string_view approximate, Tensor& out) {
+  ET_LOG_AND_RETURN_IF_FALSE(tensors_have_same_dtype(in, out));
+  ET_LOG_MSG_AND_RETURN_IF_FALSE(
+      approximate == "tanh" || approximate == "none",
+      "Invalid approximation format: %.*s for gelu",
+      static_cast<int>(approximate.length()),
+      approximate.data());
+  return true;
+}
+
+} // namespace executor
+} // namespace torch

kernels/portable/cpu/util/activation_ops_util.h

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <executorch/runtime/kernel/kernel_includes.h>
+
+namespace torch {
+namespace executor {
+
+bool check_gelu_args(const Tensor& in, string_view approximate, Tensor& out);
+
+} // namespace executor
+} // namespace torch

kernels/portable/cpu/util/targets.bzl

@@ -7,6 +7,19 @@ def define_common_targets():
     TARGETS and BUCK files that call this function.
     """
 
+    runtime.cxx_library(
+        name = "activation_ops_util",
+        srcs = ["activation_ops_util.cpp"],
+        exported_headers = [
+            "activation_ops_util.h",
+        ],
+        compiler_flags = ["-Wno-missing-prototypes"],
+        deps = [
+            "//executorch/runtime/kernel:kernel_includes",
+        ],
+        visibility = ["//executorch/kernels/portable/cpu/...", "//executorch/kernels/optimized/cpu/..."],
+    )
+
     runtime.cxx_library(
         name = "repeat_util",
         srcs = [