Add at::cpu namespace of functions for structured kernels (#49505)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/49505
I have a problem which is that static runtime needs a way to bypass
dispatch and call into kernels directly. Previously, it used
native:: bindings to do this; but these bindings no longer exist
for structured kernels! Enter at::cpu: a namespace of exactly
at:: compatible functions that assume all of their arguments are
CPU and non-autograd! The header looks like this:
```
namespace at {
namespace cpu {
CAFFE2_API Tensor & add_out(Tensor & out, const Tensor & self, const Tensor & other, Scalar alpha=1);
CAFFE2_API Tensor add(const Tensor & self, const Tensor & other, Scalar alpha=1);
CAFFE2_API Tensor & add_(Tensor & self, const Tensor & other, Scalar alpha=1);
CAFFE2_API Tensor & upsample_nearest1d_out(Tensor & out, const Tensor & self, IntArrayRef output_size, c10::optional<double> scales=c10::nullopt);
CAFFE2_API Tensor upsample_nearest1d(const Tensor & self, IntArrayRef output_size, c10::optional<double> scales=c10::nullopt);
CAFFE2_API Tensor & upsample_nearest1d_backward_out(Tensor & grad_input, const Tensor & grad_output, IntArrayRef output_size, IntArrayRef input_size, c10::optional<double> scales=c10::nullopt);
CAFFE2_API Tensor upsample_nearest1d_backward(const Tensor & grad_output, IntArrayRef output_size, IntArrayRef input_size, c10::optional<double> scales=c10::nullopt);
}}
```
This slows down static runtime because these are not the "allow
resize of nonzero tensor" variant binding (unlike the ones I had manually
written). We can restore this: it's a matter of adding codegen smarts to
do this, but I haven't done it just yet since it's marginally more
complicated.
In principle, non-structured kernels could get this treatment too.
But, like an evil mastermind, I'm withholding it from this patch, as an extra
carrot to get people to migrate to structured muahahahaha.
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Test Plan: Imported from OSS
Reviewed By: smessmer
Differential Revision: D25616105
Pulled By: ezyang
fbshipit-source-id: 84955ae09d0b373ca1ed05e0e4e0074a18d1a0b5
pytorch
2ab49701 - Add at::cpu namespace of functions for structured kernels (#49505)
