On Mon, 3 Dec 2007, Jakub Jelinek wrote:
> On Mon, Dec 03, 2007 at 09:17:22AM +0100, Thomas Gleixner wrote:
> > I looked at the disassembly but I can not spot the problem.
> >
> > I think the real problem is somewhere else. Likely candidates are
> > hrtimer_forward() or hrtimer_start() - in that order.
>
> Should be hopefully fixed in latest Fedora gcc. The problem was in code like
> typedef union { long long int s; } U;
> typedef struct { U u; } S;
>
> void foo (S *s, long long int x, unsigned long int y)
> {
> s->u = ({ (U) { .s = s->u.s + x * y }; });
> }
>
> where a backport of a recent optimization of mine, without which gcc handles
> terribly initializers from compound literals (which is something hrtimer
> uses just everywhere - why can't ktime.h for #if BITS_PER_LONG == 64 ||
> defined(CONFIG_KTIME_SCALAR)
> just use a scalar rather than union with a scalar in it??),
Of course just to annoy you :)
Seriously, we want the same code/initializers for both the scalar and the
sec/nsec case. That's where the union comes from.
Thanks,
tglx
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