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    SubjectRe: Can we drop upstream Linux x32 support?
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    * Rich Felker:

    > On Thu, Dec 13, 2018 at 05:04:59PM +0100, Florian Weimer wrote:
    >> * Rich Felker:
    >>
    >> >> If the compiler can handle the zeroing, that would be great, though not
    >> >> sure how (some __attribute__((zero)) which generates a type constructor
    >> >> for such structure; it kind of departs from what the C language offers).
    >> >
    >> > The compiler fundamentally can't. At the very least it would require
    >> > effective type tracking, which requires shadow memory and is even more
    >> > controversial than -fstrict-aliasing (because in a sense it's a
    >> > stronger version thereof).
    >>
    >> It's possible to do it with the right types. See _Bool on 32-bit Darwin
    >> PowerPC for an example, which is four bytes instead of the usual one.
    >>
    >> Similarly, we could have integer types with trap representations.
    >> Whether it is a good idea is a different matter, but the amount of
    >> compiler magic required is actually limited.
    >
    > If you do this you just have LP64 with value range restricted to
    > 32-bit.

    You have to a type different from long int for the relevant struct
    fields. This type would have zero padding.

    Florian

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