From: Stephen Hemminger <[EMAIL PROTECTED]>
Date: Tue, 6 Mar 2007 16:00:55 -0800
> On Wed, 7 Mar 2007 00:24:35 +0200
> Sami Farin <[EMAIL PROTECTED]> wrote:
>
> > On Tue, Mar 06, 2007 at 23:53:49 +0200, Sami Farin wrote:
> > ...
> > > And I found bug in gcc-4.1.2, it gave 0 for ncubic results
> > > when doing 1000 loops test... gcc-4.0.3 works.
> >
> > Found it.
> >
> > --- cbrt-test.c~ 2007-03-07 00:20:54.735248105 +0200
> > +++ cbrt-test.c 2007-03-07 00:21:03.964864343 +0200
> > @@ -209,7 +209,7 @@
> >
> > __asm__("bsrl %1,%0\n\t"
> > "cmovzl %2,%0"
> > - : "=&r" (r) : "rm" (x), "rm" (-1));
> > + : "=&r" (r) : "rm" (x), "rm" (-1) : "memory");
> > return r+1;
> > }
> >
> > Now Linux 2.6 does not have "memory" in fls, maybe it causes
> > some gcc funnies some people are seeing.
> >
>
> That code was copy-paste from:
> include/asm-x86_64/bitops.h
>
> So shouldn't both fls() and ffs() be fixed there as well?
This code doesn't modify memory behind gcc's back, so this
"memory" clobber shouldn't really be needed.
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