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From: Jan Hubicka <hubicka@ucw.cz>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: "Jan Hubicka" <hubicka@ucw.cz>, "Martin Liška" <mliska@suse.cz>,
	"gcc-pat >> GCC Patches" <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] ICF: move readonly decision for variables to the right place
Date: Fri, 06 Mar 2015 19:08:00 -0000	[thread overview]
Message-ID: <20150306190808.GA7764@kam.mff.cuni.cz> (raw)
In-Reply-To: <CAMe9rOpOYpXoHiHZq1o1TvkZHwr1JjeJQvCCSSYkpLvyMyz49Q@mail.gmail.com>

> 
> This caused:
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65334

This is another alias issue exposed by ICF.  Vectorizer attempts to increase an alignment of alias
by modifying its DECL_ALIGN, but it doesnot really achieve it - when outputting the definition we
use DECL_ALIGN of the ultimate_alias_target.

Frankly, increasing alias target is not safe thing to do: alias may be static,
while target interposable and we do not want code touching actual target to
assume greater alignment.  I suppose only way to get this right is to make
varasm to walk all aliases and figure largest alignment assumed.  I am workign
on a patch.

Honza
> 
> -- 
> H.J.

      reply	other threads:[~2015-03-06 19:08 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-01  0:15 Martin Liška
2015-03-01  0:26 ` Jan Hubicka
2015-03-02  0:58   ` Jan Hubicka
2015-03-02  7:53     ` Jan Hubicka
2015-03-02  9:47       ` Martin Liška
2015-03-06 14:38       ` H.J. Lu
2015-03-06 19:08         ` Jan Hubicka [this message]

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