[PATCH] D28508: [NVPTX] Implement NVPTXTargetLowering::getSqrtEstimate.

[Justin Lebar via Phabricator via llvm-commits]

jlebar added a comment.

> This seems to indicate that, if I'm reading the code correctly, we have a bug here for other backends for sqrt() when no extra iterations are requested (it will directly return the rsqrt estimate instead of the proper sqrt estimate)

Wow, what an amazingly broken api.

How's this for a plan: Let me implement this function correctly for NVPTX and check in a test.  Then I will at the very least improve the comment on the virtual function and try to contact the backend owners.  I would normally volunteer to refactor the API, but it seems that nobody is testing it, otherwise they would have realized that it is broken, so I'm pretty hesitant to go after it myself.


https://reviews.llvm.org/D28508