pytorch

ccab6680 - [not for land yet] hacky fix for x.ndim followed by sub (#53120)

[not for land yet] hacky fix for x.ndim followed by sub (#53120) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/53120 Currently there is a pattern which is not handled correctly by FX graph mode quantization: ``` def forward(self, x): ndim = x.ndim # or add, mul, div, etc x = torch.sub(x, ndim) return x ``` The reason this does not work is as follows: 1. x.ndim becomes a getattr node 2. the real world type of x.ndim is an integer, but this is not known from the graph (yet) 3. binary ops such as `torch.sub` require quantization of inputs 4. the framework inserts an observer to observe the output of `ndim` 5. the observer fails because `ndim` is not a Tensor For now, we hack a bandaid to unblock some teams, none of this is for land. We will have to think of a better fix which is landable (TBD). Test Plan: ``` python test/test_quantization.py TestQuantizeFx.test_getattr_with_nontensor_result ``` Imported from OSS Reviewed By: jerryzh168 Differential Revision: D26756180 fbshipit-source-id: c0e498766b22c23df74fbb5aaeaa237c4c944263