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Re: [PATCH] Fix optimization regression in constant folder


> Because, as we've said again and again, TYPE_IS_SIZETYPE doesn't imply
> any semantics to the rest of us.  

Yes, but we're trying to develop those semantics now.  When we finish
figuring out what they are, it seems best to use that flag to mean that
rather than invent some other flag.

> You are the oracle of TYPE_IS_SIZETYPE.  The rest of us don't know
> what it means.  That's we keep going around and around this circle.

I've said "what it means" but somehow that's not good enough.  It
means that these are values that are used only in very specific
calculations so we're able to prove things about those calculations
that we can't for other expressions.  That means we know whether or
not certain optimizations are safe.  This thread is all about one of those.

> TYPE_IGNORE_OVERFLOW does have semantics.

Yes, but those semantics don't happen to agree with what sizetypes mean!


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