Add copy_ (pytorch#2432)

Summary: Pull Request resolved: pytorch#2432

Reviewed By: JacobSzwejbka

Differential Revision: D54909962

fbshipit-source-id: d3cca3e8c6d3406dc502ca62fa58f0bce2a3ae4d

kernels/portable/cpu/op_copy.cpp

@@ -57,6 +57,33 @@ Tensor& copy_out(
   return out;
 }
 
+Tensor&
+copy_(RuntimeContext& ctx, Tensor& in, const Tensor& src, bool non_blocking) {
+  (void)ctx;
+  // Right now we only support blocking data transfer
+  ET_KERNEL_CHECK(ctx, non_blocking == false, InvalidArgument, in);
+
+  ET_KERNEL_CHECK(
+      ctx, tensor_is_broadcastable_to(src, in), InvalidArgument, in);
+
+  ScalarType in_type = in.scalar_type();
+  ScalarType src_type = src.scalar_type();
+
+  ET_SWITCH_REAL_TYPES_AND(Bool, in_type, ctx, "copy_", CTYPE, [&]() {
+    ET_SWITCH_REAL_TYPES_AND(Bool, src_type, ctx, "copy_", CTYPE_SRC, [&]() {
+      apply_binary_elementwise_fn<CTYPE, CTYPE_SRC, CTYPE>(
+          [](const CTYPE val_in, const CTYPE_SRC val_src) {
+            return convert<CTYPE, CTYPE_SRC>(val_src);
+          },
+          in,
+          src,
+          in);
+    });
+  });
+
+  return in;
+}
+
 } // namespace native
 } // namespace executor
 } // namespace torch

kernels/portable/functions.yaml

@@ -253,6 +253,11 @@
     - arg_meta: null
       kernel_name: torch::executor::copy_out
 
+- op: copy_
+  kernels:
+    - arg_meta: null
+      kernel_name: torch::executor::copy_
+
 - op: cos.out
   kernels:
     - arg_meta: null

kernels/test/op_copy_test.cpp

@@ -115,6 +115,13 @@ class OpCopyTest : public OperatorTest {
   }
 };
 
+class OpCopyInplaceTest : public OperatorTest {
+ protected:
+  Tensor& op_copy_(Tensor& self, const Tensor& src, bool non_blocking) {
+    return torch::executor::aten::copy_(context_, self, src, non_blocking);
+  }
+};
+
 // regular test for copy.out
 TEST_F(OpCopyTest, AllRealDtypesSupported) {
 #define TEST_ENTRY(ctype, dtype) test_dtype<ctype, ScalarType::dtype>();
@@ -255,3 +262,23 @@ TEST_F(OpCopyTest, DynamicShapeUnbound) {
   test_dynamic_shape(
       {1, 1}, torch::executor::TensorShapeDynamism::DYNAMIC_UNBOUND);
 }
+
+TEST_F(OpCopyInplaceTest, SmokeTest) {
+  TensorFactory<ScalarType::Int> tf;
+  Tensor in = tf.zeros({2, 2});
+  Tensor src = tf.make(/*sizes=*/{2, 2}, /*data=*/{1, 2, 3, 4});
+  bool non_blocking = false;
+  op_copy_(in, src, non_blocking);
+  Tensor expected = tf.make(/*sizes=*/{2, 2}, /*data=*/{1, 2, 3, 4});
+  EXPECT_TENSOR_EQ(in, expected);
+}
+
+TEST_F(OpCopyInplaceTest, BroadCastSrcSupported) {
+  TensorFactory<ScalarType::Int> tf;
+  Tensor in = tf.make(/*sizes=*/{2, 2}, /*data=*/{1, 2, 3, 4});
+  Tensor src = tf.make(/*sizes=*/{1, 2}, /*data=*/{3, 3});
+  bool non_blocking = false;
+  op_copy_(in, src, non_blocking);
+  Tensor expected = tf.make(/*sizes=*/{2, 2}, /*data=*/{3, 3, 3, 3});
+  EXPECT_TENSOR_EQ(in, expected);
+}