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Re: [PATCH] Add a new option "-fmerge-bitfields" (patch / doc inside)
- From: Richard Biener <rguenther at suse dot de>
- To: Bernd Schmidt <bschmidt at redhat dot com>
- Cc: Daniel Gutson <daniel dot gutson at tallertechnologies dot com>, Andrew Pinski <pinskia at gmail dot com>, Zoran Jovanovic <Zoran dot Jovanovic at imgtec dot com>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, Bernhard Reutner-Fischer <rep dot dot dot nop at gmail dot com>
- Date: Wed, 17 Feb 2016 14:55:44 +0100 (CET)
- Subject: Re: [PATCH] Add a new option "-fmerge-bitfields" (patch / doc inside)
- Authentication-results: sourceware.org; auth=none
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On Wed, 17 Feb 2016, Richard Biener wrote:
> On Wed, 17 Feb 2016, Bernd Schmidt wrote:
>
> >
> >
> > On 02/17/2016 02:18 PM, Daniel Gutson wrote:
> > > On Wed, Nov 26, 2014 at 5:46 AM, Andrew Pinski <pinskia@gmail.com> wrote:
> >
> > > > FYI. This causes gfc_add_interface_mapping in fortrant/trans-expr.c to
> > > > be miscompiled for aarch64-linux-gnu. I am still debugging it and
> > > > trying to get a smaller testcase.
> > >
> > > Hello,
> > >
> > > is there any update on this?
> >
> > Is this a PR somewhere?
>
> I think there are several. But rather than a special pass I hope
> we can get to lowering all bitfield accesses somewhere and make
> our regular passes deal with the combining. I've had multiple
> approaches at this but never went through finalizing them
> (tried doing that too early all the times I guess).
Whee. 2011 - https://gcc.gnu.org/ml/gcc-patches/2011-06/msg01233.html.
I remember updating this for DECL_BIT_FIELD_REPRESENTATIVE we have now,
simplifying this. I also remember doing the lowering (using
DECL_BIT_FIELD_REPRESENTATIVE) at gimplification time. And then
bitfield lowering was part of the original mem-ref branch (that didn't
get merged).
Richard.