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From: "olegendo at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/53513] SH Target: Add support for fschg and fpchg insns
Date: Mon, 17 Mar 2014 14:23:00 -0000	[thread overview]
Message-ID: <bug-53513-4-qZELqxJOBO@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-53513-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53513

--- Comment #10 from Oleg Endo <olegendo at gcc dot gnu.org> ---
(In reply to Kazumoto Kojima from comment #9)
> Although it seems that (1)-(5) in #3 are interesting points, they
> are almost optimizations.  

Yep.  Those are not necessary to get the functionality (of not using
__fpscr_values).

> I guess that programs with frequent FP
> mode switchings are simply rare in real world and would be a bit
> special or even pathological in the first place.
> I like the idea of mode switching without __fpscr_values even if it
> requires more instructions on SH4.  Now SH4 is a fairy old core and
> is not for heavy FP computations anyway.  I think that it won't impact
> the real working set.
> It looks to me that Christian's patch is the way to go.

Yep.  However, when the patch was proposed there were some objections regarding
the modifications in lcm.c (if I'm not mistaken).  We could try again.

The reason why I brought up (1)-(5) in #3 was that if one of them is eventually
implemented (e.g. reorder calculation insns) the changes to lcm.c might not be
required and could be avoided.  Depending on the implementation of such
optimization, the mode switch information might have to be obtained/maintained
in a different way.  However, I at the moment I have no concrete ideas/plans. 
If Christian's patch is accepted, that's cool, too.


  parent reply	other threads:[~2014-03-17 14:23 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-29  1:51 [Bug target/53513] New: " olegendo at gcc dot gnu.org
2013-03-10 19:54 ` [Bug target/53513] " olegendo at gcc dot gnu.org
2013-07-31 17:12 ` olegendo at gcc dot gnu.org
2014-03-13 20:48 ` olegendo at gcc dot gnu.org
2014-03-16 20:47 ` olegendo at gcc dot gnu.org
2014-03-16 23:32 ` olegendo at gcc dot gnu.org
2014-03-17  1:30 ` bugdal at aerifal dot cx
2014-03-17  9:09 ` olegendo at gcc dot gnu.org
2014-03-17 11:53 ` chrbr at gcc dot gnu.org
2014-03-17 13:51 ` kkojima at gcc dot gnu.org
2014-03-17 14:23 ` olegendo at gcc dot gnu.org [this message]
2014-03-17 15:18 ` chrbr at gcc dot gnu.org
2014-03-17 15:41 ` olegendo at gcc dot gnu.org
2014-05-12  8:47 ` chrbr at gcc dot gnu.org
2014-10-11 21:28 ` olegendo at gcc dot gnu.org
2014-10-11 22:02 ` olegendo at gcc dot gnu.org
2014-10-11 22:09 ` olegendo at gcc dot gnu.org
2014-10-12 14:13 ` olegendo at gcc dot gnu.org
2014-10-13  6:57 ` [Bug target/53513] [SH] Add support for fschg and fpchg insns and improve fenv support olegendo at gcc dot gnu.org
2014-10-13 14:40 ` olegendo at gcc dot gnu.org
2014-10-14  3:46 ` olegendo at gcc dot gnu.org
2014-10-14 12:26 ` olegendo at gcc dot gnu.org
2014-10-15  0:06 ` olegendo at gcc dot gnu.org
2014-10-15  1:00 ` olegendo at gcc dot gnu.org
2014-10-15  4:02 ` kkojima at gcc dot gnu.org
2014-10-15  8:41 ` olegendo at gcc dot gnu.org
2014-10-15 17:57 ` olegendo at gcc dot gnu.org
2014-10-15 22:08 ` olegendo at gcc dot gnu.org
2014-10-16  1:13 ` kkojima at gcc dot gnu.org
2014-10-16 10:59 ` olegendo at gcc dot gnu.org
2014-10-16 12:12 ` olegendo at gcc dot gnu.org
2014-10-16 13:28 ` kkojima at gcc dot gnu.org
2014-10-16 18:57 ` olegendo at gcc dot gnu.org
2014-10-17  9:22 ` olegendo at gcc dot gnu.org
2014-10-17 17:42 ` olegendo at gcc dot gnu.org
2014-10-17 22:20 ` olegendo at gcc dot gnu.org
2014-10-17 23:16 ` kkojima at gcc dot gnu.org
2014-12-07 23:20 ` olegendo at gcc dot gnu.org
2014-12-10  0:22 ` olegendo at gcc dot gnu.org
2014-12-10  8:32 ` olegendo at gcc dot gnu.org
2014-12-13 13:18 ` olegendo at gcc dot gnu.org
2014-12-14 14:00 ` [Bug target/53513] [SH] Add support for fpchg insn " olegendo at gcc dot gnu.org
2014-12-16 21:29 ` olegendo at gcc dot gnu.org
2014-12-21 17:54 ` olegendo at gcc dot gnu.org

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