Re: PR 21438 : Warning about division by zero depends on lexical form

["Manuel López-Ibáñez" <lopezibanez at gmail dot com>]

On 29/01/07, Mark Mitchell <mark@codesourcery.com> wrote:
> Manuel López-Ibáñez wrote:
>
> > 2007-01-14  Andrew Pinski  <pinskia@gmail.com>
> >                    Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
> >
> >  PR c/21438
> >  * gcc/c-typeck.c (build_binary_op): Don't give division by zero
> > warning if integer zero is promoted to REAL_TYPE.
> >
> > testsuite:
> > 2007-01-14  Andrew Pinski  <pinskia@gmail.com>
> >                    Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
> >
> >  PR c/21438
> >  * gcc.dg/Wdiv-by-zero.c: New.
>
> I'll let a C maintainer review these bits.

It seems that, as Dirk explains, this is  actually the intended behaviour:

Joseph says: "the C front end doesn't
warn for division by a floating point zero constant (although it warns for
division of a floating point value by an integer zero) since explicit
division by 0.0 is used as a way of generating Inf and NaN."
http://gcc.gnu.org/ml/gcc-patches/2006-01/msg02184.html

So I think that the PR is invalid and thus this patch is useless. :-(

Am I wrong?

Manuel.