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Re: PATCH: Align DImode to 4 byte for i386

From: "H.J. Lu" <hjl dot tools at gmail dot com>
To: "Jan Hubicka" <jh at suse dot cz>
Cc: "Jan Hubicka" <hubicka at ucw dot cz>, gcc-patches at gcc dot gnu dot org, "Richard Guenther" <richard dot guenther at gmail dot com>, ubizjak at gmail dot com, "Arnaud Charlet" <charlet at adacore dot com>
Date: Sat, 9 Feb 2008 16:09:06 -0800
Subject: Re: PATCH: Align DImode to 4 byte for i386
References: <20080204031135.GA7865@lucon.org> <20080204110635.GD1757@kam.mff.cuni.cz> <84fc9c000802040309pd4ca9eag7a7cb1265943ee65@mail.gmail.com> <20080204112433.GB1026@kam.mff.cuni.cz> <20080204143842.GB10805@lucon.org> <20080204161849.GH1757@kam.mff.cuni.cz> <20080204165223.GA11416@lucon.org> <20080205022218.GA27992@atrey.karlin.mff.cuni.cz> <6dc9ffc80802090838t6e269d27h2989d5396a26266d@mail.gmail.com> <20080209234457.GQ1026@kam.mff.cuni.cz>

On Feb 9, 2008 3:44 PM, Jan Hubicka <jh@suse.cz> wrote:
> > Apparently, it breaks Ada. But Ada may be broken/different in long
> > long alignment. I still believe
> > my patch doesn't break the psABI.
>
> I also agree that the patch can hardly break psABI when alignment of 4
> is specified.  The question is why it breaks Ada.
>
> We used to have BIGGEST_ALIGNMENT set to 32. This was later revised to
> support SSE modes and we now have BIGGEST_ALIGNMENT set to 128 and
> ADJUST_FIELD_ALIGNMENT and friends responsible for reducing the
> alignment of stuff to 32bit per psABI specification.
>
> It seems to me that some of ABI stuff is not being adjusted as it ought.
> Do you have any idea what breaks?
>

Ada compiler is written in Ada. I don't know Ada and have no idea where to look.
Arnaud, do you have any idea why aligning long long to 4 byte breaks Ada?

Thanks.

H.J.
to

Follow-Ups:
- Re: PATCH: Align DImode to 4 byte for i386
  - From: Arnaud Charlet
- Re: PATCH: Align DImode to 4 byte for i386
  - From: Eric Botcazou

References:
- PATCH: Align DImode to 4 byte for i386
  - From: H.J. Lu
- Re: PATCH: Align DImode to 4 byte for i386
  - From: Jan Hubicka
- Re: PATCH: Align DImode to 4 byte for i386
  - From: H.J. Lu
- Re: PATCH: Align DImode to 4 byte for i386
  - From: Jan Hubicka

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