[PATCH] D28335: [WIP] [RFC] Don't lower floating point intrinsics to libcalls which modify errno

[Steve Canon via Phabricator via llvm-commits]

scanon added a comment.

In https://reviews.llvm.org/D28335#832394, @efriedma wrote:

> Huh, I guess we do use the x87 sin/cos.  It's probably a terrible idea (the microcoded routines are both slow and wildly inaccurate for large inputs), but we do it.


fsin/fcos can be wildly inaccurate even for relatively modest arguments (https://randomascii.wordpress.com/2014/10/09/intel-underestimates-error-bounds-by-1-3-quintillion/). We really shouldn’t ever generate them unless the user specifically asks for them.


Repository:
  rL LLVM

https://reviews.llvm.org/D28335