Re: [PATCH][RFC] Fix PR30364, reassociation not allowed for undefined overflow

["Richard Guenther" <richard dot guenther at gmail dot com>]

On 6/22/07, Rask Ingemann Lambertsen <rask@sygehus.dk> wrote:
> On Sat, Feb 24, 2007 at 10:58:41PM +0100, Richard Guenther wrote:
> >
> > 2007-02-21  Richard Guenther  <rguenther@suse.de>
> >
> >       PR middle-end/30364
> >       * fold-const.c (fold_binary): Do not associate expressions
> >       with more than one variable for integer types that do not wrap.
> >
> >       * gcc.dg/torture/pr30364-1.c: New testcase.
> >       * gcc.dg/torture/pr30364-2.c: Likewise.
> >       * gcc.dg/torture/pr30364-3.c: Likewise.
> >
> > Index: testsuite/gcc.dg/torture/pr30364-1.c
> > ===================================================================
> > *** testsuite/gcc.dg/torture/pr30364-1.c      (revision 0)
> > --- testsuite/gcc.dg/torture/pr30364-1.c      (revision 0)
> > ***************
> > *** 0 ****
> > --- 1,19 ----
> > + /* { dg-do run } */
> > +
> > + extern void abort (void);
> > +
> > + int f(int a, int b)
> > + {
> > +   if (a > 0x7FFFFFF0) return 0;
> > +   if (b > 0x7FFFFFF0) return 0;
> > +
> > +   int c = (a - 20) + (b - 20);
> > +   return c > 0x7FFFFFF0;
> > + }
> > +
> > + int main()
> > + {
> > +   if (f (0x7FFFFFF0, 41) != 1)
> > +     abort ();
> > +   return 0;
> > + }
>
>    1) This tests nothing on hosts where int is 64 bits.

Which would be?

>    2) This will always fail on hosts where int is 16 bits.

Do they all have SImode?  In which case we could use a
SImode type.  Feel free to do so or file a bugreport to remind me
(you can assign it to me).

Richard.