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From: "enkovich.gnu at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/64317] [5 Regression] Ineffective allocation of PIC base register
Date: Fri, 13 Feb 2015 08:06:00 -0000	[thread overview]
Message-ID: <bug-64317-4-FO8kg0mfCY@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-64317-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64317

--- Comment #11 from Ilya Enkovich <enkovich.gnu at gmail dot com> ---
(In reply to Vladimir Makarov from comment #10)
> I guess it is easy to check by preventing pic pseudo generation.

i386 back-end doesn't support fixed PIC register any more.  This test case
demonstrates performance regression in some EEMBC 1.1 tests caused by pseudo
PIC register introduction.

It is unclear why RA decided to spill PIC register.  If we look at loop's code
then we see PIC register is used in each line of code and seems to be the most
used register.

It also seems weird to me that code for the first loop becomes much better
(with no PIC reg fills) if we restrict inlining for the other one.  How does
the second loop affect allocation in the first one?


  parent reply	other threads:[~2015-02-13  8:06 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-15 15:03 [Bug rtl-optimization/64317] New: " izamyatin at gmail dot com
2014-12-15 15:07 ` [Bug rtl-optimization/64317] " rguenth at gcc dot gnu.org
2015-01-13 10:26 ` rguenth at gcc dot gnu.org
2015-01-23 20:17 ` vmakarov at gcc dot gnu.org
2015-02-05 12:22 ` enkovich.gnu at gmail dot com
2015-02-06  9:52 ` jakub at gcc dot gnu.org
2015-02-06 10:06 ` enkovich.gnu at gmail dot com
2015-02-10 22:17 ` vmakarov at gcc dot gnu.org
2015-02-12 21:04 ` law at redhat dot com
2015-02-13  3:35 ` vmakarov at gcc dot gnu.org
2015-02-13  3:37 ` vmakarov at gcc dot gnu.org
2015-02-13  8:06 ` enkovich.gnu at gmail dot com [this message]
2015-02-19 13:18 ` law at redhat dot com
2015-02-19 16:21 ` vmakarov at gcc dot gnu.org
2015-02-20 23:24 ` law at redhat dot com
2015-02-21 20:10 ` vmakarov at gcc dot gnu.org
2015-02-27 23:07 ` vmakarov at gcc dot gnu.org
2015-03-03 19:08 ` law at redhat dot com
2015-03-03 22:39 ` law at redhat dot com
2015-03-04 17:39 ` law at redhat dot com
2015-03-05 15:37 ` vmakarov at gcc dot gnu.org
2015-03-05 20:01 ` law at redhat dot com
2015-03-09 17:12 ` law at redhat dot com
2015-03-23  7:53 ` law at gcc dot gnu.org
2015-03-23  7:54 ` law at redhat dot com

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