[PATCH] D147871: ValueTracking: Implement computeKnownFPClass for sqrt

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added inline comments.


================
Comment at: llvm/lib/Analysis/ValueTracking.cpp:4737-4738
+          Known.knownNot(fcPosInf);
+        if (KnownSrc.isKnownNever(fcSNan))
+          Known.knownNot(fcSNan);
+
----------------
foad wrote:
> Is this valid? You haven't implemented snan logic for most of the other intrinsics.
Yes, I need to go back to refine this. You are never allowed to introduce signaling nans. Non-constrained ops just don't guarantee quieting. The propagateNaN helper introduced later helps with this (although it doesn't quite apply here since there are additional nan conditions 


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D147871/new/

https://reviews.llvm.org/D147871