This is the mail archive of the
mailing list for the GCC project.
Re: [tree-ssa] mainline->branch merge status
Richard Henderson <firstname.lastname@example.org> writes:
> On Fri, Jan 30, 2004 at 12:25:28AM +0100, Andreas Schwab wrote:
>> > So does the other way; *(void **)__o->next_free = ... is exactly what you
>> > can't do.
>> I don't follow. __o->next_free is a character pointer, thus can alias all
>> other pointers.
> No, that's not correct. "char" can alias any other data; "char *" is
> not so unconstrained. The code above is in fact broken.
I still don't understand. Aliasing is a property of pointers, not of
numbers, isn't it? Thus we have "__o->next_free", which is "char *" and
"(void **)__o->next_free", which is "void **". The former can be an
alias of the latter, thus storing through the latter can change the
contents of the former. Did I miss something?
Andreas Schwab, SuSE Labs, email@example.com
SuSE Linux AG, Maxfeldstraße 5, 90409 Nürnberg, Germany
Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."