[PATCH] D116952: [ConstantFolding] Flush folded denormals to zero when using fastmath

Sat Jan 29 01:27:07 PST 2022

nikic added a reviewer: lebedev.ri.
nikic requested changes to this revision.
nikic added a comment.
This revision now requires changes to proceed.

Definitely not a fan of this change, on multiple levels. I don't particularly look forward to having a TTI dependency in constant folding, but more immediately, I don't think I really understand the LangRef basis for this change.

Could you explain which constituent part of `fast` FMF specifically allows this optimization? I don't see anything related to denormals, and interpreting `afn` to apply to primitive operations would be a bit of a stretch.

How does this relate to the `denormal-fp-math` function attribute? I would have thought that this is the one that controls denormal flushing behavior.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D116952/new/

https://reviews.llvm.org/D116952