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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug rtl-optimization/50677] volatile forces load into register
Date: Sun, 09 Oct 2011 17:36:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50677

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011-10-09
     Ever Confirmed|0                           |1

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-10-09 17:36:30 UTC ---
Well, the issue is that most optimization passes just don't do anything
for volatile qualified accesses.  That's a safe thing.  Deciding what
kind of optimizations are allowed for volatile accesses might introduce bugs,
and sofar the consensus was "volatile?  don't bother with optimization, it'll
be slow anyway".

It very likely is combine that gives up here.