[PATCH] D60021: InstSimplify: Fold round intrinsics from sitofp

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

> I'm not sure where or if there are official docs for libm

The official definitions of all the libm floating-point functions for IEEE754 floating-point are in the C standard, Annex F.

As far as I can tell, your reasoning is right.  sitofp/uitofp must produce either an integral finite result, or +inf/-inf. If sitofp/uitofp produces an integral finite result, all these rounding functions do nothing.  And if sitofp produces an infinity, all these rounding functions also do nothing, as explicitly stated in Annex F.


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  https://reviews.llvm.org/D60021/new/

https://reviews.llvm.org/D60021