remove allow_shape_mismatch in Tensor.replace (#14536)

move all logic to torch_backend and not hacking Tensor method

extra/torch_backend/backend.py

@@ -29,6 +29,10 @@ def wrap(x: Tensor) -> torch.Tensor:
   x._strides = strides_for_shape(x.shape) # always recalculate
   if (not hasattr(x, '_storage_offset')) or (not x.uop.is_realized): x._storage_offset = calculate_storage_offset(x)
   return mod.wrap(x, _to_torch_dtype(x.dtype), _to_torch_device(x.device).index)
+def _update_torch_metadata(tensor: torch.Tensor, tiny: Tensor) -> None:
+  tiny._strides = strides_for_shape(tiny.shape)
+  tiny._storage_offset = calculate_storage_offset(tiny)
+  mod.update_metadata(tensor, tiny.shape, tiny._strides, tiny._storage_offset)
 def unwrap(x:torch.Tensor) -> Tensor:
   assert isinstance(x, torch.Tensor), f"x isn't {type(x)}"
   return mod.unwrap(x)
@@ -611,7 +615,10 @@ tiny_backend = {**{k:wrap_out(v) for k,v in tiny_backend_out.items()}, **{
   "aten.fill_.Tensor": lambda self, value: Tensor.full(self.shape, value.reshape(()).item(), device=self.device, dtype=self.dtype),
   "aten.flip": Tensor.flip,
   "aten.scatter_reduce.two": Tensor.scatter_reduce,
-  "aten.squeeze_.dim": lambda self, dim: self.replace(self.squeeze(dim), allow_shape_mismatch=True), # TODO: inplace view op, here?
+  "aten.squeeze_.dim": Tensor.squeeze,
+  "aten.unsqueeze_": Tensor.unsqueeze,
+  "aten.transpose_": Tensor.transpose,
+  "aten.t_": Tensor.transpose,
   "aten.add.Tensor": lambda input,other,alpha=1: input+alpha*other,
   "aten.linspace": lambda start, stop, steps, dtype=None, **kwargs:
     Tensor.linspace(start, stop, steps, **({"dtype": _from_torch_dtype(dtype)} if dtype is not None else {})),
@@ -655,6 +662,13 @@ inplace_ops = {
   "aten.masked_fill_.Tensor",
 }
 
+inplace_view_ops = {
+  "aten.squeeze_.dim",
+  "aten.unsqueeze_",
+  "aten.transpose_",
+  "aten.t_",
+}
+
 def wrap_fxn(k,f):
   def nf(*args, **kwargs):
     if TORCH_DEBUG:
@@ -675,8 +689,42 @@ def wrap_inplace(k,f):
     return orig
   return nf
 
+def wrap_inplace_view_op(k,f):
+  def nf(*args, **kwargs):
+    orig = args[0]
+    args, kwargs = unwrap_args(args, kwargs)
+    target = args[0]
+    new_view = f(*args, **kwargs)
+    if new_view is target or new_view.uop is target.uop:
+      _update_torch_metadata(orig, target)
+      return orig
+    base = canonical_base(target)
+    op = (f, args[1:], kwargs)
+    if target is base:
+      views = derived_views(base)
+      if views:
+        old_base = Tensor(base.uop, device=base.device)
+        old_base.requires_grad = base.requires_grad
+        old_base._views = getattr(base, "_views", set())
+        for v in views: v._view_base = old_base
+        base._views = set()
+        base._view_base = old_base
+        base._view_ops = [op]
+        old_base._views.add(weakref.ref(base))
+    else:
+      target._view_base = base
+      base._views = getattr(base, "_views", set())
+      base._views.add(weakref.ref(target))
+      target._view_ops = _get_view_ops(target) + [op]
+    target.uop = new_view.uop
+    _update_torch_metadata(orig, target)
+    return orig
+  return nf
+
 for k,v in tiny_backend.items():
-  wrapper = wrap_inplace if k in inplace_ops else wrap_fxn
+  if k in inplace_view_ops: wrapper = wrap_inplace_view_op
+  elif k in inplace_ops: wrapper = wrap_inplace
+  else: wrapper = wrap_fxn
   torch.library.impl(k.replace("aten.", "aten::"), "privateuseone")(wrapper(k,v))
 
 @torch.library.impl("aten::equal", "privateuseone")

extra/torch_backend/test_inplace.py

@@ -67,5 +67,37 @@ class TestTorchBackendInplace(unittest.TestCase):
     d += torch.arange(4)
     np.testing.assert_array_equal(a.cpu(), torch.arange(4).cpu())
 
+  def test_inplace_view_metadata(self):
+    a = torch.arange(6, dtype=torch.float32).reshape(1, 2, 3)
+    ret = a.squeeze_(0)
+    self.assertIs(ret, a)
+    self.assertEqual(a.shape, torch.Size([2, 3]))
+    ret = a.unsqueeze_(1)
+    self.assertIs(ret, a)
+    self.assertEqual(a.shape, torch.Size([2, 1, 3]))
+    ret = a.transpose_(0, 2)
+    self.assertIs(ret, a)
+    self.assertEqual(a.shape, torch.Size([3, 1, 2]))
+
+  def test_t_inplace_metadata(self):
+    a = torch.arange(6, dtype=torch.float32).reshape(2, 3)
+    ret = a.t_()
+    self.assertIs(ret, a)
+    self.assertEqual(a.shape, torch.Size([3, 2]))
+    expected = torch.arange(6, dtype=torch.float32).reshape(2, 3).t()
+    np.testing.assert_array_equal(a.cpu().numpy(), expected.cpu().numpy())
+
+  def test_squeeze_matmul(self):
+    # squeeze_ is used internally by PyTorch for vector-matrix matmul (unsqueeze -> mm -> squeeze_)
+    a = torch.arange(65, dtype=torch.float32)
+    b = torch.arange(65*45, dtype=torch.float32).reshape(65, 45)
+    result = a.matmul(b)
+    self.assertEqual(result.shape, torch.Size([45]))
+    # verify correctness
+    a_cpu = torch.arange(65, dtype=torch.float32, device='cpu')
+    b_cpu = torch.arange(65*45, dtype=torch.float32, device='cpu').reshape(65, 45)
+    expected = a_cpu.matmul(b_cpu)
+    np.testing.assert_allclose(result.cpu().numpy(), expected.numpy(), rtol=1e-4, atol=1e-4)
+
 if __name__ == "__main__":
   unittest.main()

extra/torch_backend/wrapped_tensor.cpp

@@ -131,7 +131,15 @@ py::object unwrap_tensor(const at::Tensor &tensor) {
   return py::reinterpret_borrow<py::object>(tiny->ptr(getPyInterpreter()));
 }
 
+void update_metadata(const at::Tensor &tensor, const std::vector<int64_t> &sizes,
+                     const std::vector<int64_t> &strides, int64_t storage_offset) {
+  auto* impl = tensor.unsafeGetTensorImpl();
+  impl->set_allow_tensor_metadata_change(true);
+  impl->set_sizes_and_strides(sizes, strides, storage_offset);
+}
+
 PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
   m.def("wrap", &wrap_tensor);
   m.def("unwrap", &unwrap_tensor);
+  m.def("update_metadata", &update_metadata);
 }

tinygrad/tensor.py

@@ -276,12 +276,12 @@ class Tensor(OpMixin):
       run_schedule(*Tensor.schedule_with_vars(*to_realize), do_update_stats=do_update_stats)
     return self
 
-  def replace(self, x:Tensor, allow_shape_mismatch=False) -> Tensor:
+  def replace(self, x:Tensor) -> Tensor:
     """
     Replaces the data of this tensor with the data of another tensor. Only the shape of the tensors must match.
     """
     # used for replacing a Tensor with a new version of it (potentially with a different device and dtype)
-    assert self.shape == x.shape or allow_shape_mismatch, f"replace shape mismatch {self.shape} != {x.shape}"
+    assert self.shape == x.shape, f"replace shape mismatch {self.shape} != {x.shape}"
     self.uop = x.uop
     return self