Don't fastpath conj copy when conj/neg bit mismatch (#108881)

Fixes https://github.com/pytorch/pytorch/issues/106051

Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/108881
Approved by: https://github.com/soulitzer

aten/src/ATen/native/Copy.cpp

@@ -253,7 +253,9 @@ static Tensor & copy_impl(Tensor & self, const Tensor & src, bool non_blocking)
       self.storage_offset() == src.storage_offset() &&
       self.strides().equals(src.strides()) &&
       self.sizes().equals(src.sizes()) &&
-      self.scalar_type() == src.scalar_type()
+      self.scalar_type() == src.scalar_type() &&
+      self.is_conj() == src.is_conj() &&
+      self.is_neg() == src.is_neg()
     );
   if (is_same_data) {
     return self;

test/test_complex.py

@@ -25,6 +25,14 @@ class TestComplexTensor(TestCase):
             x = torch.tensor([3., 3. + 5.j], device=device)
         self.assertEqual(x.dtype, torch.cdouble if dtype == torch.float64 else torch.cfloat)
 
+    @dtypes(*complex_types())
+    def test_conj_copy(self, device, dtype):
+        # issue: https://github.com/pytorch/pytorch/issues/106051
+        x1 = torch.tensor([5 + 1j, 2 + 2j], device=device, dtype=dtype)
+        xc1 = torch.conj(x1)
+        x1.copy_(xc1)
+        self.assertEqual(x1, torch.tensor([5 - 1j, 2 - 2j], device=device, dtype=dtype))
+
     @onlyCPU
     @dtypes(*complex_types())
     def test_eq(self, device, dtype):

test/test_torch.py

@@ -3125,6 +3125,10 @@ else:
             dst._neg_view().copy_(src)
             self.assertEqual(dst, src.neg(), exact_dtype=False)
 
+            # issue: https://github.com/pytorch/pytorch/issues/106051
+            dst._neg_view().copy_(dst)
+            self.assertEqual(dst, src, exact_dtype=False)
+
         for dst_dtype, src_dtype in [
                 (torch.complex64, torch.complex64),
                 (torch.complex128, torch.complex64),