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

[escha via Phabricator via llvm-commits]

escha added a comment.

Don't be too embarrassed; when we switched internally from an rcp(rsqrt(x)) expansion to x * rsqrt(x), we *also* completely missed this, and literally only found the bug when it showed up as internal test failures. The new expansion was even brought up and talked about at a team meeting and signed off by multiple people, and nobody thought to consider the number zero, myself included.


Repository:
  rL LLVM

https://reviews.llvm.org/D28508