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From: "chen3.liu at intel dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/94452] I386 ABI: How to determine the alignment
 arguments on the stack of struct or union for argument passing
Date: Thu, 02 Apr 2020 09:18:38 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94452

--- Comment #5 from ChenLiu <chen3.liu at intel dot com> ---
(In reply to Richard Biener from comment #4)
> (In reply to ChenLiu from comment #2)
> > (In reply to Richard Biener from comment #1)
> > > I see gx aligned to 64 bytes (as I expected).  Can you be more specif=
ic as
> > > to what target you tested?
> >=20
> > I tested on i386 target. I think you may misunderstand what I mean. The=
 gx
> > will align to 4 byte when passing it on stack. I think this should belo=
ng to
> > calling conventions.
>=20
> Ah, OK.  IIRC the psABI does not factor in over/under alignment but only
> size and kind of (sub-)objects so eventually extra copy-in/out is required
> to have the callee see arguments of the desired alignment.
>=20
> HJ can probably clarify.
>=20
> Note bugzilla isn't really for this kind of questions, there's a psABI
> mailing list somewhere.

Thanks for your help.=