nathan@codesourcery.com (Nathan Sidwell) wrote on 03.05.05 in
<42778D99.7070904@codesourcery.com>:
Mike Stump wrote:
int avail;
int main() {
while (*(volatile int *)&avail == 0)
continue;
return 0;
}
Ok, so, the question is, should gcc produce code that infinitely
loops,
or should it be obligated to actually fetch from memory? Hint, 3.3
fetched.
I beleive the compiler is so licensed. [5.1.2.3/2] talks about
accessing
a volatile object. If the compiled can determine the actual object
being accessed through a series of pointer and volatile cast
conversions,
then I see nothing in the std saying it must behave as-if the object
were volatile when it is not.
This, of course, might not be useful to users :)
As a QOI issue, it would be nice if such a situation caused a warning
("ignoring volatile cast ..." or something like that).
It's rather dangerous to have the user believe that this worked as
intended when it didn't.