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Date: Thu, 02 Jun 2016 12:57:00 -0000
From: Richard Biener <rguenther@suse.de>
To: David Edelsohn <dje.gcc@gmail.com>
cc: Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org>,     GCC Patches <gcc-patches@gcc.gnu.org>, Jan Hubicka <hubicka@ucw.cz>,     "William J. Schmidt" <wschmidt@linux.vnet.ibm.com>,     Segher Boessenkool <segher@kernel.crashing.org>
Subject: Re: move increase_alignment from simple to regular ipa pass
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On Thu, 2 Jun 2016, David Edelsohn wrote:

> >>>>> Richard Biener wrote:
> 
> >> "This would mean the pass should get its own non-Optimization flag
> >> initialized by targets where section anchors are usually used"
> >> IIUC should we add a new option -fno-increase_alignment and gate the
> >> pass on it ? Um sorry I didn't understand why targets
> >> with section anchors (arm, aarch64, ppc) should initialize this option ?
> >
> > Currently the pass is only run for targets with section anchors (and there
> > by default if they are enabled by default).  So it makes sense to
> > run on those by default and the pass is not necessary on targets w/o
> > section anchors as the vectorizer can easily adjust alignment itself on
> > those.
> 
> PPC does not always enable section anchors -- it depends on the code
> model.  Shouldn't this be tied to use of section anchors?

It effectively is with the patch by walking all functions to see if they
have section anchors enabled.  That is unnecessary work for targets that
do not support section anchors at all, of course.

Richard.