This is the mail archive of the
mailing list for the GCC project.
Re: [PATCH] Relax check against commuting XOR and ASHIFTRT in combine.c
- From: Rainer Orth <ro at CeBiTec dot Uni-Bielefeld dot DE>
- To: Alan Lawrence <alan dot lawrence at arm dot com>
- Cc: "gcc-patches\ at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, Mike Stump <mikestump at comcast dot net>
- Date: Mon, 02 Feb 2015 16:47:18 +0100
- Subject: Re: [PATCH] Relax check against commuting XOR and ASHIFTRT in combine.c
- Authentication-results: sourceware.org; auth=none
- References: <53B1B4FE dot 7010201 at arm dot com> <53B1D271 dot 5000405 at redhat dot com> <53C69926 dot 4050503 at arm dot com> <53C80023 dot 6000100 at arm dot com> <5409FBB1 dot 3040509 at redhat dot com> <541AA89C dot 9070005 at arm dot com> <87ppe70wld dot fsf at igel dot home> <yddy4s7lyns dot fsf at lokon dot CeBiTec dot Uni-Bielefeld dot DE> <5449326C dot 9040301 at arm dot com> <yddsiieyard dot fsf at CeBiTec dot Uni-Bielefeld dot DE> <544A3D6E dot 4000408 at arm dot com> <ydd1tpx1ura dot fsf at CeBiTec dot Uni-Bielefeld dot DE> <544A8698 dot 5060309 at arm dot com> <yddvbjpiswz dot fsf at lokon dot CeBiTec dot Uni-Bielefeld dot DE> <54CF8AA9 dot 1070303 at arm dot com>
>> I'm still not really comfortable with those target lists; they tend to
>> artificially exclude tests on targets where they are perfectly capable
>> of running. At least with the comments added, it's better than before
>> with no explanation whatsoever. Perhaps Mike can weigh in here?
> Well, it's been awhile, but on further reflection - my feeling is that we
> should be dropping the target lists here too. Maybe we end up introducing a
> dg-skip-if that grows over time, but it'd have to grow quite a bit to reach
> the size of the dg-do target we'd otherwise have...
It's not even necessary to use dg-skip if the scan-rtl-dump fails. You
can just add an xfail there, which has the advantage that you do notice
if the test starts to pass e.g. due to changes in a target.
> However I am a bit wary about dropping the dg-do target constraint just as
> we are nearing a release! So if we were to keep the whitelist approach,
> your patch looks good to me, and I'd be happy if that were committed.
Let's give others a day or two to comment: if nobody is in favour of the
more agressive approach, I'll commit my patch.
Rainer Orth, Center for Biotechnology, Bielefeld University