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Re: [PATCH] Fix optimization regression in constant folder
firstname.lastname@example.org (Richard Kenner) writes:
> > But the rest of us don't understand the semantics of sizetypes. That
> > is why we are trying to pin it down in terms of other flags. We
> > understand what those other flags mean.
> The problem is that it's becoming clearer and clearer that the semantics of
> sizetypes CAN'T be expressed in terms of those other flags!
The flags aren't fixed in stone. In fact, I just introduced them
earlier this year. So all this tells me is that we need to change the
flags. I already proposed such a change
(http://gcc.gnu.org/ml/gcc-patches/2007-10/msg00053.html). Nobody has
yet explained why my proposal wouldn't work.
> Essentially, what we have to do when we see a transformation that might
> potentially be applied to sizetypes is to rely on our understanding of
> the semantics of those operations to see whether or not that transformation
> is safe or not.
> That set of decisions may or may not corespond to some other set of flags
> that we're using for other (unrelated) types. I don't see it as a big deal
> if it doesn't.
Again, it's a big deal because at the moment most of the gcc
maintainers don't understand the semantics. After all this discussion
I still barely have a handle on what you want. You are talking in
vague generalities, and you are unable to give us any actual code.
It's no wonder we remain confused.