[PATCH] D46535: Correct warning on Float->Integer conversions.

[Erich Keane via Phabricator via cfe-commits]

erichkeane added a comment.

In https://reviews.llvm.org/D46535#1253473, @xbolva00 wrote:

> Hello, @erichkeane
>
> I am working on int to float checker but I haven't found yet a way how to check if integer fits to float's significant bits. Maybe you can recommend me something? I already tried some LLVM APIs but no success. (cc @spatel as you will probably know the right function to do it)


I'm not sure what you mean by that... Every Integer is representable (lossy of course) as a float as far as I know.  You'll obviously lose the LSDs, but it'll be representable.  Are you trying to check whether it is round-trip-able?  If thats the case, I think you'll need to make sure it entirely fits in the mantissa.  You can get the amount of mantissa bits by checking the APFloat's fltSemantics.  There are a couple of builtin ones that I think end up being useful, but the 'precision' field seems like what you want.


Repository:
  rC Clang

https://reviews.llvm.org/D46535