> On Mon, Oct 26, 2020 at 10:14 AM Jan Hubicka <hubi...@ucw.cz> wrote:
> >
> > > >
> > > > For example you had patch that limited "rep cmpsb" expansion for
> > > > -minline-all-stringops. Now the conditions could be
> > > > -minline-all-stringops || optimize_insn_for_size () == OPTIMIZE_SIZE_MAX
> > > > since it is still useful size optimization.
> > > >
> > > > I am not sure if you had other changes of this nature? (It is bit hard
> > > > to grep compiler for things like this and I would like to get these
> > > > organized to optimize_size levels now).
> > >
> > > Shouldn't it apply to all functions inlined by -minline-all-stringops?
> >
> > I think we handle the other cases, for code optimized for size we go for
> > ix86_size_memcpy and ix86_size_memset tables that say inline all with
> > rep movsb. We do not inline strlen since the way it is implemented gets
> > too long (short inline version would be welcome).
> >
> > I will look through backend, but if you are aware of more checks like
> > one in ix86_expand_cmpstrn_or_cmpmem which disable size optimization
> > even at -Os, let me know. They are not that easy to find...
> >
>
> [hjl@gnu-cfl-2 gcc]$ cat /tmp/x.c
> int
> func (char *d, unsigned int l)
> {
> return __builtin_strncmp (d, "foo", l) ? 1 : 2;
> }
> [hjl@gnu-cfl-2 gcc]$ gcc -c -Os /tmp/x.c
> [hjl@gnu-cfl-2 gcc]$ nm x.o
> 0000000000000000 T func
> U strncmp
> [hjl@gnu-cfl-2 gcc]$ size x.o
> text data bss dec hex filename
> 138 0 0 138 8a x.o
> [hjl@gnu-cfl-2 gcc]$ gcc -c -O2 /tmp/x.c
> [hjl@gnu-cfl-2 gcc]$ size x.o
> text data bss dec hex filename
> 146 0 0 146 92 x.o
> [hjl@gnu-cfl-2 gcc]$ nm x.o
> 0000000000000000 T func
> [hjl@gnu-cfl-2 gcc]$
>
> -Os shouldn't inline strncmp.
Interesting, I woul dexpect cmpsb still win. Well, this makes it
easeir. Sorry for delaying the patches - somehow I got them connected
with the -Os refactoring.
Honza
>
> --
> H.J.
