Daniel Berlin wrote: > Again, I'd love to just ignore this and say "we don't care".
Ugh. I think you're right that the standard says that we only get to assume non-aliasing when the pointed-to memory is modified, so all-parameters-restrict is actually weaker than -fargument-noalias. How unfortunate. I've CC'd Joseph in the hopes that his C standards knowledge will suggest a different answer. > But we should not do it by saying "oh, well, this could never effect > anything". It could. You can come up with transformations that > break, and they all involve the compiler claiming a and b can't alias > when they can. Indeed. The most obvious example is: return a != b; If the compiler "knows" the pointers don't alias, the compiler will happily, but wrongly, fold that to 1. -- Mark Mitchell CodeSourcery [EMAIL PROTECTED] (650) 331-3385 x713