From: Paul Koning <paulkoning@comcast.net>
To: Joern Rennecke <joern.rennecke@embecosm.com>
Cc: Jan-Benedict Glaw <jbglaw@lug-owl.de>,
"gcc@gcc.gnu.org Development" <gcc@gcc.gnu.org>
Subject: Re: [buildrobot] pdp11-aout
Date: Tue, 26 Nov 2013 16:47:00 -0000 [thread overview]
Message-ID: <E0AFE2A9-CF42-40F4-8269-98B1CFF0C5F8@comcast.net> (raw)
In-Reply-To: <CAMqJFCp1s7wrH2W3da3ccHnsm6CY0869NDfdEhw_crJW-1CXdg@mail.gmail.com>
On Nov 26, 2013, at 11:03 AM, Joern Rennecke <joern.rennecke@embecosm.com> wrote:
> On 26 November 2013 15:55, Paul Koning <paulkoning@comcast.net> wrote:
>
>> Is there a requirement that all targets must have branch cost that it, at least some of the time, 4 or greater?
>
> Not by design, although there seem to be a number of issues with
> supporting targets with a lower branch cost. E.g. consider
> LOGICAL_OP_NON_SHORT_CIRCUIT - the default of which also seems to
> assume superscalarity and a cheap flag-set operation - and its impact
> on/treatment by the test suite.
The doc says that the default branch cost is 1. So it seems reasonable for a target to have branch cost < 4 at all times, if the target doesn't have expensive branches or widely varying branch costs. Low speed processors with simple execution units are likely to be such targets (and indeed the pdp11 is a good example).
>
>> If so, why? If not, then I suppose cfgexpand.c could be changed to defeat this message
>
> I agree.
>
> , but how, or why?
>
> Changing this target macro into a target hook should do the trick.
Is there such a target hook in the current code?
paul
next prev parent reply other threads:[~2013-11-26 16:47 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-26 3:20 [buildrobot] First results of running contrib/config-list.mk Jan-Benedict Glaw
2013-11-26 3:24 ` [buildrobot] alpha64-dec-vms / alpha-dec-vms Jan-Benedict Glaw
2013-11-26 8:30 ` Tristan Gingold
2013-11-26 3:25 ` [buildrobot] vax-linux-gnu / vax-netbsdelf Jan-Benedict Glaw
2013-11-26 3:25 ` [buildrobot] score-elf --enable-obsolete Jan-Benedict Glaw
2013-11-26 3:25 ` [buildrobot] x86_64-w64-mingw32 Jan-Benedict Glaw
2013-11-27 15:41 ` Fixed! (was: [buildrobot] x86_64-w64-mingw32) Jan-Benedict Glaw
2013-11-26 3:25 ` [buildrobot] vax-openbsd Jan-Benedict Glaw
2013-11-26 3:25 ` [buildrobot] rx-elf Jan-Benedict Glaw
2013-11-26 3:26 ` [buildrobot] rl78-elf Jan-Benedict Glaw
2013-11-26 3:26 ` [buildrobot] x86_64-knetbsd-gnu Jan-Benedict Glaw
2013-11-26 3:26 ` [buildrobot] moxie-elf / moxie-rtems / moxie-uclinux Jan-Benedict Glaw
2013-11-26 3:26 ` [buildrobot] pdp11-aout Jan-Benedict Glaw
2013-11-26 15:56 ` Paul Koning
2013-11-26 16:05 ` Joern Rennecke
2013-11-26 16:08 ` Joern Rennecke
2013-11-26 16:47 ` Paul Koning [this message]
2013-11-26 16:26 ` Jeff Law
2013-11-26 3:27 ` [buildrobot] microblaze-elf / microblaze-linux Jan-Benedict Glaw
2013-11-26 15:51 ` Michael Eager
2013-11-26 16:08 ` Jan-Benedict Glaw
2013-11-26 16:13 ` Michael Eager
2013-11-26 16:17 ` Jan-Benedict Glaw
2013-11-26 17:16 ` Michael Eager
2013-11-26 3:27 ` [buildrobot] i686-openbsd3.0 Jan-Benedict Glaw
2013-11-26 3:27 ` [buildrobot] lm32-elf / lm32-rtems / lm32-uclinux Jan-Benedict Glaw
2013-11-26 3:28 ` [buildrobot] i686-mingw32crt Jan-Benedict Glaw
2013-11-27 15:25 ` Fixed! (was: [buildrobot] i686-mingw32crt) Jan-Benedict Glaw
2013-11-26 3:28 ` [buildrobot] cris-linux / crisv32-linux Jan-Benedict Glaw
2013-11-26 3:28 ` [buildrobot] ia64-hpux Jan-Benedict Glaw
2013-11-27 2:50 ` Jan-Benedict Glaw
2013-11-27 3:41 ` Jeff Law
2013-11-27 8:15 ` Alexander Ivchenko
2013-11-27 10:15 ` Fixed! (was: [buildrobot] ia64-hpux) Jan-Benedict Glaw
2013-11-26 3:28 ` [buildrobot] i686-interix3 --enable-obsolete Jan-Benedict Glaw
2013-11-27 16:39 ` Jan-Benedict Glaw
2013-11-26 3:28 ` [buildrobot] ia64-hp-vms Jan-Benedict Glaw
2013-11-26 3:28 ` [buildrobot] mep-elf Jan-Benedict Glaw
2013-11-27 8:22 ` Jan-Benedict Glaw
2013-11-27 9:29 ` Joern Rennecke
2013-11-26 3:29 ` [buildrobot] epiphany-elf Jan-Benedict Glaw
2013-11-26 19:49 ` Fixed! (was: [buildrobot] epiphany-elf) Jan-Benedict Glaw
2013-11-26 3:29 ` [buildrobot] c6x-elf / c6x-uclinux Jan-Benedict Glaw
2013-11-26 3:29 ` [buildrobot] cr16-elf Jan-Benedict Glaw
2013-11-26 3:29 ` [buildrobot] fr30-elf Jan-Benedict Glaw
2013-11-26 3:30 ` [buildrobot] avr-rtems Jan-Benedict Glaw
2013-11-26 8:27 ` Jan-Benedict Glaw
2013-11-26 3:30 ` [buildrobot] bfin-elf / bfin-linux-uclibc / bfin-openbsd / bfin-uclinux Jan-Benedict Glaw
2013-11-26 14:54 ` [buildrobot] First results of running contrib/config-list.mk Ian Lance Taylor
2013-11-26 16:58 ` Joseph S. Myers
2013-12-02 11:08 ` Gerald Pfeifer
2013-12-02 11:15 ` Jan-Benedict Glaw
2013-12-02 16:34 ` Joseph S. Myers
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