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Re: volatile semantics


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 :)

nathan

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Nathan Sidwell    ::   http://www.codesourcery.com   ::     CodeSourcery LLC
nathan@codesourcery.com    ::     http://www.planetfall.pwp.blueyonder.co.uk


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