> -----Ursprüngliche Nachricht-----
> Von: Gcc-help <gcc-help-bounces@xxxxxxxxxxx> Im Auftrag von Segher
> Boessenkool
> Gesendet: Mittwoch, 13. Januar 2021 22:46
> An: Fredrik Noring <noring@xxxxxxxxxx>
> Cc: gcc-help@xxxxxxxxxxx; Alexander Monakov <amonakov@xxxxxxxxx>
> Betreff: Re: m68k: Simple loop compiles into boundless recursion with -O2
>
> On Wed, Jan 13, 2021 at 08:53:13PM +0100, Fredrik Noring wrote:
> > > For the archives, no one has said it yet: to just disable the
> > > optimisation transforming the loop into a memset, you can use
> > > -fno-tree-loop-distribute-patterns .
> >
> > It's a new 32-bit libc (for Atari TOS), and maximum GCC optimisations
> > are welcome, although I haven't yet figured out exactly where the
> > boundary is between the GCC built-ins and this libc implementation.
> > There is obviously some overlap between the two, and I wouldn't want
> > the libc to stand in the way of GCC's optimisations.
>
> You would use this flag only for compiling the memset (etc.) routines
> themselves. Maybe using a pragma or similar.
>
>
> Segher
e.g. this one:
__attribute__((optimize("no-tree-loop-distribute-patterns")))
void *memset2(void *s, int c, unsigned int n)
{
...
Stefan
