On Thu, Jul 30, 2015 at 10:29 AM, Marek Polacek <pola...@redhat.com> wrote: > On Wed, Jul 29, 2015 at 04:44:46PM -0600, Jeff Law wrote: >> On 07/29/2015 08:08 AM, Marek Polacek wrote: >> >As discussed elsewhere, -Wtautological-compare shouldn't warn about >> >floating-point types because of the way NaN behave. >> > >> >I've been meaning to commit this one as obvious, but I'm not sure >> >whether I should also use HONOR_NANS or whether I can safely ignore >> >that here. >> > >> >Bootstrapped/regtested on x86_64-linux, ok for trunk? >> > >> >2015-07-29 Marek Polacek <pola...@redhat.com> >> > >> > * c-common.c (warn_tautological_cmp): Bail for float types. >> > >> > * c-c++-common/Wtautological-compare-3.c: New test. >> I think it comes down to what we think users are going to expect when >> compiling code with NaNs disabled. >> >> One camp would probably say "in my code X == X is always true since I don't >> have NaNs." The other might say "whether or not to warn on X == X should >> not be dependent on flags such as -ffinite-math-only". >> >> I could easily make a case for either. I'd personally tend to lean towards >> the latter. > > Me too. I hope I won't upset anyone by committing this patch now. I just > don't want glibc folks to trip over this for too long.
I agree with doing this unconditionally. Richard. > Thanks, > > Marek
