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Re: lib{atomic, itm}/configure.tgt uses -mcpu=v9 as default for sparc
- From: Matthias Klose <doko at debian dot org>
- To: Eric Botcazou <ebotcazou at adacore dot com>, Carlos Sánchez de La Lama <csanchezdll at gmail dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: Tue, 03 Jun 2014 11:38:35 +0200
- Subject: Re: lib{atomic, itm}/configure.tgt uses -mcpu=v9 as default for sparc
- Authentication-results: sourceware.org; auth=none
- References: <daz8upf8y2z dot fsf at sdf dot lonestar dot org> <4871468 dot TDuAmUELpQ at polaris> <dazwqcz7d9e dot fsf at sdf dot lonestar dot org> <3271892 dot bKmkptFVPT at polaris>
Am 02.06.2014 22:30, schrieb Eric Botcazou:
>> I have successfully built without the switch, but I am not sure of the
>> effects at runtime.
>
> For sure libitm cannot work, there is a 'flushw' in config/sparc/sjlj.S.
>
>> If V9 is indeed required, is there a way to build without those libs? Or
>> has pre V9 support been dropped at some point?
>
> No, V8 is still supported, but nobody has ported the libraries to it.
>
>> IMHO an efficiency enhancement should not prevent running less
>> efficiently on a supported architecture. If target triple is
>> sparcv9-*-*, the next case will match and will add the "-mcpu=v9" to
>> XCFLAGS, but adding it for non-v9 sparc-*-* targets is at least weird.
>
> Well, V9 is about 20 years old now so defaulting to it is not unreasonable,
> especially for all the native OSes. But patches are of course welcome.
V9 is currently bound to 64bit, you can't build a sparc-linux-gnu compiler
defaulting to V9 without patches. But anyway, Debian did drop the sparc port
two months ago anyway.
Matthias