Add fused add_relu op. (#39342)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/39342
Many networks such as resnet have adds followed by relu. This op is the
first step in enabling this fused implementation.
Once we have the fused add_relu op, a JIT pass will be written to
replace add + relu patterns with add_relu.
Test Plan:
python test/test_nn.py TestAddRelu
Imported from OSS
Differential Revision: D21822397
fbshipit-source-id: 03df83a3e46ddb48a90c5a6f755227a7e361a0e8
