[clang-tools-extra] r250824 - Apply modernize-use-default to clang-tools-extra.

[Tobias Grosser via cfe-commits]

On 10/20/2015 11:37 PM, David Blaikie wrote:
>
>
> On Tue, Oct 20, 2015 at 2:24 PM, Tobias Grosser via cfe-commits
> <cfe-commits at lists.llvm.org <mailto:cfe-commits at lists.llvm.org>> wrote:
>
>     On 10/20/2015 02:56 PM, Angel Garcia Gomez via cfe-commits wrote:
>
>         Author: angelgarcia
>         Date: Tue Oct 20 07:56:27 2015
>         New Revision: 250824
>
>         URL: http://llvm.org/viewvc/llvm-project?rev=250824&view=rev
>         Log:
>         Apply modernize-use-default to clang-tools-extra.
>
>         Summary: Replace empty bodies of default constructors and
>         destructors with '= default'.
>
>
>     Hi Angel,
>
>     this breaks http://lab.llvm.org:8011/builders/perf-x86_64-penryn-O3.
>     The builder runs gcc 4.7.2.
>
>
> Ah, I was/am seeing this on the GDB 7.5 buildbot too - but figured it
> might be GCC 4.6, because I couldn't reproduce similar behavior in small
> samples on GCC 4.7, but it might be that I have GCC 4.7.3 locally, not
> 4.7.2...
>
> I think I have some ideas on how to fix this while keeping the change,
> but probably best to revert first, then try some things once we've got a
> reproduction locally to experiment with. (I think maybe Optional and
> possibly some other types are missing noexcept on their user-defined
> dtors, and GCC 4.old is assuming user defined dtors are noexcept(false),
> which is incorrect in C++11)

This seems to be the same issue (or at least a similar issue) to what we 
had seen in the Polly source. It would be interesting to understand what 
is going on.

Best,
Tobias