<div dir="ltr">It was not supported before but there was a workaround in Clang. As far as I recall, it basically "secretly" provided a typedef for __float128 (presumably to long double on most targets). This workaround was in place precisely to allow these headers to compile.<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Apr 15, 2016 at 7:58 PM, James Y Knight <span dir="ltr"><<a href="mailto:jyknight@google.com" target="_blank">jyknight@google.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">I'm confused: why does it break targets if __float128 wasn't supported before, and still isn't supported?<div><br></div><div>Surely enabling float128 support on some targets, and leaving it disabled on linux/x86 shouldn't actually *break* linux/x86?</div></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Apr 15, 2016 at 11:53 AM, Nemanja Ivanovic via cfe-commits <span dir="ltr"><<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>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?<br><br></div>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:<br><br>/* Define if __float128 is supported on this host. */<br>#define _GLIBCXX_USE_FLOAT128 1<br><br></div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Apr 15, 2016 at 4:14 PM, Nico Weber <span dir="ltr"><<a href="mailto:thakis@chromium.org" target="_blank">thakis@chromium.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div><div>On Fri, Apr 15, 2016 at 12:27 AM, Hal Finkel <span dir="ltr"><<a href="mailto:hfinkel@anl.gov" target="_blank">hfinkel@anl.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div><div>----- Original Message -----<br>
> From: "Hans Wennborg via cfe-commits" <<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>><br>
> To: "Nemanja Ivanovic" <<a href="mailto:nemanja.i.ibm@gmail.com" target="_blank">nemanja.i.ibm@gmail.com</a>>, "Nico Weber" <<a href="mailto:thakis@chromium.org" target="_blank">thakis@chromium.org</a>><br>
> Cc: "cfe-commits" <<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>><br>
> Sent: Thursday, April 14, 2016 8:07:58 PM<br>
> Subject: Re: r266186 - Enable support for __float128 in Clang<br>
><br>
> On Wed, Apr 13, 2016 at 2:49 AM, Nemanja Ivanovic via cfe-commits<br>
> <<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>> wrote:<br>
> > Author: nemanjai<br>
> > Date: Wed Apr 13 04:49:45 2016<br>
> > New Revision: 266186<br>
> ><br>
> > URL: <a href="http://llvm.org/viewvc/llvm-project?rev=266186&view=rev" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project?rev=266186&view=rev</a><br>
> > Log:<br>
> > Enable support for __float128 in Clang<br>
> ><br>
> > This patch corresponds to review:<br>
> > <a href="http://reviews.llvm.org/D15120" rel="noreferrer" target="_blank">http://reviews.llvm.org/D15120</a><br>
> ><br>
> > It adds support for the __float128 keyword, literals and a target<br>
> > feature to<br>
> > enable it. This support is disabled by default on all targets and<br>
> > any target<br>
> > that has support for this type is free to add it.<br>
> ><br>
> > Based on feedback that I've received from target maintainers, this<br>
> > appears to<br>
> > be the right thing for most targets. I have not heard from the<br>
> > maintainers of<br>
> > X86 which I believe supports this type. I will subsequently<br>
> > investigate the<br>
> > impact of enabling this on X86.<br>
><br>
> We're seeing build errors when targeting Android, which I think may<br>
> be<br>
> caused by this:<br>
><br>
> [...]<br>
> In file included from ../../v8/src/base/functional.cc:11:<br>
> In file included from ../../v8/src/base/functional.h:13:<br>
> In file included from<br>
> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/functional:55:<br>
> In file included from<br>
> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/tuple:38:<br>
> In file included from<br>
> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/utility:70:<br>
> In file included from<br>
> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/stl_pair.h:59:<br>
> In file included from<br>
> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/move.h:57:<br>
> /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/type_traits:269:39:<br>
> error: __float128 is not supported on this target<br>
> struct __is_floating_point_helper<__float128><br>
> ^<br>
><br>
> (From<br>
> <a href="https://build.chromium.org/p/tryserver.chromium.android/builders/linux_android_rel_ng/builds/54128/steps/compile%20%28with%20patch%29/logs/stdio" rel="noreferrer" target="_blank">https://build.chromium.org/p/tryserver.chromium.android/builders/linux_android_rel_ng/builds/54128/steps/compile%20%28with%20patch%29/logs/stdio</a>)<br>
><br>
> Any idea what might be breaking here?<br>
<br>
</div></div>Yep, see: <a href="http://reviews.llvm.org/D19125" rel="noreferrer" target="_blank">http://reviews.llvm.org/D19125</a></blockquote><div><br></div></div></div><div>Since this is breaking real-world code, is it possible to revert this until <a href="http://reviews.llvm.org/D19125" target="_blank">http://reviews.llvm.org/D19125</a> is ready?</div><span><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><br>
<br>
-Hal<br>
<br>
><br>
> Thanks,<br>
> Hans<br>
<div><div>> _______________________________________________<br>
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><br>
<br>
</div></div><span><font color="#888888">--<br>
Hal Finkel<br>
Assistant Computational Scientist<br>
Leadership Computing Facility<br>
Argonne National Laboratory<br>
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