r266186 - Enable support for __float128 in Clang

Fri Apr 15 10:58:50 PDT 2016

I'm confused: why does it break targets if __float128 wasn't supported
before, and still isn't supported?

Surely enabling float128 support on some targets, and leaving it disabled
on linux/x86 shouldn't actually *break* linux/x86?

On Fri, Apr 15, 2016 at 11:53 AM, Nemanja Ivanovic via cfe-commits <
cfe-commits at lists.llvm.org> wrote:

> I have just pinged the patch to see if I can get it approved today. Can I
> give it a few hours and if it isn't approved by tonight, I'll revert the
> other patch?
>
> BTW. a temporary workaround for this issue if absolutely required in the
> next few hours is to comment out the following define in bits/config.h:
>
> /* Define if __float128 is supported on this host. */
> #define _GLIBCXX_USE_FLOAT128 1
>
>
> On Fri, Apr 15, 2016 at 4:14 PM, Nico Weber <thakis at chromium.org> wrote:
>
>> On Fri, Apr 15, 2016 at 12:27 AM, Hal Finkel <hfinkel at anl.gov> wrote:
>>
>>> ----- Original Message -----
>>> > From: "Hans Wennborg via cfe-commits" <cfe-commits at lists.llvm.org>
>>> > To: "Nemanja Ivanovic" <nemanja.i.ibm at gmail.com>, "Nico Weber" <
>>> thakis at chromium.org>
>>> > Cc: "cfe-commits" <cfe-commits at lists.llvm.org>
>>> > Sent: Thursday, April 14, 2016 8:07:58 PM
>>> > Subject: Re: r266186 - Enable support for __float128 in Clang
>>> >
>>> > On Wed, Apr 13, 2016 at 2:49 AM, Nemanja Ivanovic via cfe-commits
>>> > <cfe-commits at lists.llvm.org> wrote:
>>> > > Author: nemanjai
>>> > > Date: Wed Apr 13 04:49:45 2016
>>> > > New Revision: 266186
>>> > >
>>> > > URL: http://llvm.org/viewvc/llvm-project?rev=266186&view=rev
>>> > > Log:
>>> > > Enable support for __float128 in Clang
>>> > >
>>> > > This patch corresponds to review:
>>> > > http://reviews.llvm.org/D15120
>>> > >
>>> > > It adds support for the __float128 keyword, literals and a target
>>> > > feature to
>>> > > enable it. This support is disabled by default on all targets and
>>> > > any target
>>> > > that has support for this type is free to add it.
>>> > >
>>> > > Based on feedback that I've received from target maintainers, this
>>> > > appears to
>>> > > be the right thing for most targets. I have not heard from the
>>> > > maintainers of
>>> > > X86 which I believe supports this type. I will subsequently
>>> > > investigate the
>>> > > impact of enabling this on X86.
>>> >
>>> > We're seeing build errors when targeting Android, which I think may
>>> > be
>>> > caused by this:
>>> >
>>> > [...]
>>> > In file included from ../../v8/src/base/functional.cc:11:
>>> > In file included from ../../v8/src/base/functional.h:13:
>>> > In file included from
>>> >
>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/functional:55:
>>> > In file included from
>>> > /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/tuple:38:
>>> > In file included from
>>> >
>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/utility:70:
>>> > In file included from
>>> >
>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/stl_pair.h:59:
>>> > In file included from
>>> >
>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/move.h:57:
>>> >
>>> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/type_traits:269:39:
>>> > error: __float128 is not supported on this target
>>> >     struct __is_floating_point_helper<__float128>
>>> >                                       ^
>>> >
>>> > (From
>>> >
>>> https://build.chromium.org/p/tryserver.chromium.android/builders/linux_android_rel_ng/builds/54128/steps/compile%20%28with%20patch%29/logs/stdio
>>> )
>>> >
>>> > Any idea what might be breaking here?
>>>
>>> Yep, see: http://reviews.llvm.org/D19125
>>
>>
>> Since this is breaking real-world code, is it possible to revert this
>> until http://reviews.llvm.org/D19125 is ready?
>>
>>
>>>
>>>
>>>  -Hal
>>>
>>> >
>>> > Thanks,
>>> > Hans
>>> > _______________________________________________
>>> > cfe-commits mailing list
>>> > cfe-commits at lists.llvm.org
>>> > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>>> >
>>>
>>> --
>>> Hal Finkel
>>> Assistant Computational Scientist
>>> Leadership Computing Facility
>>> Argonne National Laboratory
>>>
>>
>>
>
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