Messages in this thread | | | Subject | Re: [PATCH] C undefined behavior fix | From | Alexandre Oliva <> | Date | 06 Jan 2002 23:40:28 -0200 |
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On Jan 6, 2002, Tom Rini <trini@kernel.crashing.org> wrote:
> On Sun, Jan 06, 2002 at 11:19:40PM +0100, Jakub Jelinek wrote: >> On Mon, Jan 07, 2002 at 08:59:47AM +1100, Paul Mackerras wrote:
>> > asm("" : "=r" (x) : "0" (y));
>> Even if gcc learned to analyze asm statements (and use it in something other >> than scheduling), I'm sure this wouldn't be optimized away exactly because >> this construct is used by various projects exactly for this purpose (make >> gcc think it can have any value allowed for the type in question).
> Yes, but there's no gaurentee of that. It'd probably break a few things > if they did, but there's nothing stopping them from doing it.
If we documented this side effect of such asm statements, one would have to come up with a very strong case to change it.
-- Alexandre Oliva Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/ Red Hat GCC Developer aoliva@{cygnus.com, redhat.com} CS PhD student at IC-Unicamp oliva@{lsd.ic.unicamp.br, gnu.org} Free Software Evangelist *Please* write to mailing lists, not to me - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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