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From: "segher at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/102024] [12 Regression] zero width bitfields and ABIs
Date: Tue, 24 Aug 2021 21:36:01 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102024

--- Comment #9 from Segher Boessenkool <segher at gcc dot gnu.org> ---
(In reply to Michael Matz from comment #8)
> So, I think, not removing those members from the FE makes sense, they con=
tain
> crucial information.  Unfortunately that means that they need to be dealt
> with
> in code dealing with layout (correct) or argument/return-value passing
> (seemingly
> fishy right now for some platforms?).
>=20
> Also, all else being equal I think the C language defines the de-facto
> psABI, so any difference between C and C++ should be resolved towards C.

Yeah.  In the case of Power homogeneous arguments, removing the bitfield
from  { float a; int:0; float b; }  is fine to do *later*, when the backend
already knows it is an homogeneous argument, when all decisions have been m=
ade
and the results recorded.  It would be good if this was documented somewher=
e,
where that spot is?=