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Date: Tue, 15 Jan 2013 22:22:00 -0000
From: Zdenek Dvorak <rakdver@iuuk.mff.cuni.cz>
To: Marek Polacek <polacek@redhat.com>
Cc: Steven Bosscher <stevenb.gcc@gmail.com>,	GCC Patches <gcc-patches@gcc.gnu.org>,	Richard Guenther <rguenther@suse.de>
Subject: Re: [PATCH] Fix PR55833 + cheaper checking
Message-ID: <20130115222143.GA31497@kam.mff.cuni.cz>
References: <20130110173143.GD20218@redhat.com> <CABu31nM32xKY3gj4PXYC5X12WhJ8iCpbyxWz=ptED54UTNNVZg@mail.gmail.com> <20130110221943.GA14720@kam.mff.cuni.cz> <20130114161353.GB5414@redhat.com> <20130114175154.GA22128@kam.mff.cuni.cz> <20130114191131.GC5414@redhat.com>
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Hi,

> > Yes, you should check whether you are in an irreducible loop.  This is done by
> > testing EDGE_IRREDUCIBLE_LOOP flag,
> 
> Alright, I was wondering whether there's any other way.  Unfortunately,
> here I couldn't do something like
> 
> if (loop_preheader_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP)
>   ...
> because we're natural loop in a subloop, so I abused the loop exits of
> this loop.  Hopefully I'm not doing something evil.
> 
> Updated patch attached.  Ok if testing passes?  Thanks,

yes, this is OK,

Zdenek

> 2013-01-14  Richard Biener  <rguenther@suse.de>
> 	    Marek Polacek  <polacek@redhat.com>
> 
> 	PR rtl-optimization/55833
> 	* loop-unswitch.c (unswitch_loops): Move loop verification...
> 	(unswitch_single_loop): ...here.  Call mark_irreducible_loops.
> 	* cfgloopmanip.c (fix_loop_placement): Add IRRED_INVALIDATED parameter.
> 	Set it to true when we're removing a loop from hierarchy tree in
> 	an irreducible region.
> 	(fix_bb_placements): Adjust caller.
> 	(fix_loop_placements): Likewise.
> 
> 	* gcc.dg/pr55833.c: New test.