[ET][Portable] Check scalar overflow: op_leaky_relu

Differential Revision: [D77401091](https://our.internmc.facebook.com/intern/diff/D77401091/)

[ghstack-poisoned]

Author: manuelcandales

kernels/portable/cpu/op_leaky_relu.cpp

@@ -44,7 +44,11 @@ Tensor& leaky_relu_out(
   ET_KERNEL_CHECK(ctx, in_type == out_type, InvalidArgument, out);
 
   ET_SWITCH_FLOATHBF16_TYPES(in_type, ctx, "leaky_relu.out", CTYPE, [&]() {
-    const CTYPE negative_slope_casted = utils::scalar_to<CTYPE>(negative_slope);
+    auto opt_negative_slope_casted =
+        utils::internal::check_overflow_scalar_cast<CTYPE>(negative_slope);
+    ET_KERNEL_CHECK(
+        ctx, opt_negative_slope_casted.has_value(), InvalidArgument, );
+    auto negative_slope_casted = opt_negative_slope_casted.value();
 
     apply_unary_map_fn(
         [negative_slope_casted](const CTYPE val_in) {

kernels/test/op_leaky_relu_test.cpp

@@ -40,10 +40,29 @@ class OpLeakyReluTest : public OperatorTest {
     EXPECT_TENSOR_EQ(out, ret);
     EXPECT_TENSOR_EQ(out, tf.ones({2, 2}));
   }
+
+  template <ScalarType DTYPE>
+  void expect_bad_scalar_value_dies(const Scalar& bad_value) {
+    TensorFactory<DTYPE> tf;
+    Tensor in = tf.ones({2, 2});
+    Tensor out = tf.zeros({2, 2});
+
+    ET_EXPECT_KERNEL_FAILURE(context_, op_leaky_relu_out(in, bad_value, out));
+  }
 };
 
 TEST_F(OpLeakyReluTest, SanityCheck) {
 #define TEST_ENTRY(ctype, dtype) test_leaky_relu_dtype<ScalarType::dtype>();
   ET_FORALL_FLOATHBF16_TYPES(TEST_ENTRY);
 #undef TEST_ENTRY
 }
+
+TEST_F(OpLeakyReluTest, FloatTensorTooSmallScalarDies) {
+  /* Cannot be represented by a float. */
+  expect_bad_scalar_value_dies<ScalarType::Float>(-3.41e+38);
+}
+
+TEST_F(OpLeakyReluTest, FloatTensorTooLargeScalarDies) {
+  /* Cannot be represented by a float. */
+  expect_bad_scalar_value_dies<ScalarType::Float>(3.41e+38);
+}