r266186 - Enable support for __float128 in Clang

[Nico Weber via cfe-commits]

I've looked into this a bit, and this breaks compiling programs like
`#include <vector>` on linux, without passing any special flags (other than
`-std=gnu++11`). That seems like a very big regression :-) I think this
should be reverted, so that there's no rush for getting your other patch in.

LLVM tries to keep trunk shippable at all times, and not being able to
compile <vector> on linux seems bad :-) We're trying to actually ship clang
trunk every week or two, and this is already somewhat hard if things that
break the world are reverted and fixed asynchronously.

Can you revert, please?

On Fri, Apr 15, 2016 at 11:53 AM, Nemanja Ivanovic <nemanja.i.ibm at gmail.com>
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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