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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c/102989] Implement C2x's n2763 (_BitInt)
Date: Wed, 26 Oct 2022 08:35:55 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102989

--- Comment #24 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #23)
> What about the large ones?  Say for arbitrary size generic vectors we keep
> them in SSA form until late (generic vector lowering) and at that point
> lower, perhaps we could do the same for _BitInt?  The unary as well as mo=
st
> of binary operations  can be handled by simple loops over extraction of
> limbs from the large number, then there is multiplication and
> division/modulo.  I think the latter is why LLVM restricts it to 128 bits
> right now,

Right.

> https://gcc.gnu.org/pipermail/gcc/2022-May/thread.html#238657
> was an proposal from the LLVM side but I don't see it being actually furt=
her
> developed and don't see it on LLVM trunk.

I think work on it stalled after that thread. See also
https://discourse.llvm.org/t/rfc-add-support-for-division-of-large-bitint-b=
uiltins-selectiondag-globalisel-clang/60329/=