[PATCH] D139455: AMDGPU: Document denormal behavior

[Artem Tamazov via Phabricator via llvm-commits]

artem.tamazov added a comment.

In D139455#3996367 <https://reviews.llvm.org/D139455#3996367>, @arsenm wrote:

> We have preserve-sign behavior and ignore positive-zero mode entirely. Also the modifiers are silently ignored for ieee mode =0. I don't remember what the wrong behavior depending on the denormal mode was, beyond don't use these without flushing

I see. What I would like to emphasize is that the compiler should NOT use output modifiers for optimization when "denormal-fp-math"="preserve-sign" (in spite of modifiers will work in this mode), because output modifiers break sign preservation behavior. The compiler should use output modifiers only in "denormal-fp-math"="positive-zero" mode.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D139455/new/

https://reviews.llvm.org/D139455