commit fc68896488ca9e3bbdc8e66b07ee60749de5e622
author Jacques Pienaar <jpienaar@google.com> Wed Dec 01 20:45:08 2021 -0800
committer Copybara-Service <copybara-worker@google.com> Wed Dec 01 20:46:43 2021 -0800
tree aa974b0dea69bcda0726ff40ab7c0d31534ede18
parent 4d4a819ae972d7be5c0b8c6d49a7242c5dc09988

[mlir][drr] Simple heuristic to reduce chance of accidental nullptr dereference

When an attribute is optional & is given an additional constraint in
rewrite pattern that could lead to dereferencing null Attribute. Avoid
cases where the constraints checks attribute but has no check if null.

This should be improved to be more uniformly guarded.

GitOrigin-RevId: 86eb57b728c85bd1658f542d6ce8340efa63b4df