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From: "olegendo at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/50749] Auto-inc-dec does not find subsequent contiguous mem accesses
Date: Thu, 17 Sep 2015 14:26:00 -0000	[thread overview]
Message-ID: <bug-50749-4-yz4itFLzyo@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-50749-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50749

--- Comment #21 from Oleg Endo <olegendo at gcc dot gnu.org> ---
(In reply to Urja Rannikko from comment #20)
> I'll add a note here that this seems to also affect the AVR target when it
> is under register pressure and cant use Z or Y registers which can do Z+n
> /Y+n addressing, it ends up doing really stupid things with X register 
> ...

I don't know AVR, but if it has only two addr regs which can do post-inc loads,
in your example a loop distribution is required.  In other words, you need to
use two loops, first with p1,p2 and second loop with p3.  Because the
calculation in the loop is simple, it would make sense.  If the calculations in
the loop are more complex, maybe not.  It's similar to the problems in PR
53949.


  parent reply	other threads:[~2015-09-17 14:26 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-16 20:29 [Bug target/50749] New: SH Target: Post-increment addressing used only for first memory access oleg.endo@t-online.de
2011-10-16 23:34 ` [Bug target/50749] " kkojima at gcc dot gnu.org
2011-10-17  0:33 ` kkojima at gcc dot gnu.org
2011-10-19  0:00 ` oleg.endo@t-online.de
2011-10-19 21:37 ` kkojima at gcc dot gnu.org
2011-10-30 12:37 ` oleg.endo@t-online.de
2011-10-30 13:54 ` oleg.endo@t-online.de
2011-10-30 23:37 ` kkojima at gcc dot gnu.org
2011-11-28 22:54 ` oleg.endo@t-online.de
2011-11-29  0:25 ` kkojima at gcc dot gnu.org
2011-12-30  2:14 ` oleg.endo@t-online.de
2011-12-30  3:36 ` kkojima at gcc dot gnu.org
2012-06-12  7:10 ` [Bug middle-end/50749] Auto-inc-dec does not find subsequent contiguous mem accesses olegendo at gcc dot gnu.org
2012-08-23 14:17 ` [Bug rtl-optimization/50749] " olegendo at gcc dot gnu.org
2013-06-22 12:22 ` olegendo at gcc dot gnu.org
2013-09-30  9:06 ` amker.cheng at gmail dot com
2013-10-03 10:47 ` olegendo at gcc dot gnu.org
2013-12-06 20:28 ` olegendo at gcc dot gnu.org
2013-12-24 22:55 ` steven at gcc dot gnu.org
2015-05-22 13:57 ` olegendo at gcc dot gnu.org
2015-09-17  9:00 ` urjaman at gmail dot com
2015-09-17 14:26 ` olegendo at gcc dot gnu.org [this message]
2015-09-17 19:45 ` urjaman at gmail dot com

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