Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."

[Robert Dewar]

Richard Kenner wrote:

> I can't speak for any other GCC developer, but I personally am quite
> comfortable viewing any code that assumes wrapping semantics as broken
> and needing fixing with the exception of these cases of checking for
> overflow: there simply is no good way in C to do these checks in a portable
> manner and, as I said, I think we should make sure they continue to work
> and maybe even document that.

Now that I don't like, Richard is recommending we write in some
undefined language where wraps sometimes work and sometimes
don't. That seems the worst of all worlds to me.
> But also note that my position also is that we, as much as possible, should
> allow these "broken" legacy codes to continue to work properly despite that
> feeling, unless we have a specific case (such as the loop cases) where the
> benefits of losing the optimization are quite high and the likelihood that
> we'll break code is very low.

Yes, I agree with this