Help in tracking down unusual apparent 5.2.0 LTO issue

[Matt Godbolt]

Hi again,

I managed to get GCC5.2.0 building against binutils 2.26:

$ ~/.fighome/runtime/gcc/5.2.0-2/bin/ld.gold --version
GNU gold (DRW-internal-build 2.26.20160125) 1.11
Copyright (C) 2015 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or (at your option) a later version.
This program has absolutely no warranty

(FWIW I had to install the patch in this bug:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66259 to get it to build
in-tree).

Sadly the problem remains:

Dump of assembler code for function std::_List_node<std::function<void
()> >::~_List_node():
   0x0000000000762240 <+0>: push   %rbp
   0x0000000000762241 <+1>: mov    %rsp,%rbp
   0x0000000000762244 <+4>: sub    $0x10,%rsp
   0x0000000000762248 <+8>: mov    %rdi,-0x8(%rbp)
   0x000000000076224c <+12>: mov    -0x8(%rbp),%rax
   0x0000000000762250 <+16>: add    $0x10,%rax
   0x0000000000762254 <+20>: mov    %rax,%rdi
   0x0000000000762257 <+23>: callq  0x0
   0x000000000076225c <+28>: nop
   0x000000000076225d <+29>: leaveq
   0x000000000076225e <+30>: retq
End of assembler dump.

Any thoughts on what flags I might give to gold to try and track this
down? I tried -Wl,--debug,all and there didn't seem to be all that
much debug information.

Thanks in advance,

Matt

On Thu, Mar 17, 2016 at 8:43 AM, Matt Godbolt <matt@godbolt.org> wrote:
> Thanks; I will do. The binutils is built in-tree, and as I recall I
> had issues building with 2.25, but I see 2.26 is out now. Will report
> back here.
>
> Much obliged,
>
> Matt
>
> On Thu, Mar 17, 2016 at 8:42 AM, Markus Trippelsdorf
> <markus@trippelsdorf.de> wrote:
>> On 2016.03.17 at 08:36 -0500, Matt Godbolt wrote:
>>> One last pertinent piece of information:
>>>
>>> ~/.fighome/runtime/gcc/5.2.0-1/bin/ld.gold --version
>>> GNU gold (GCC-explorer-build 2.24) 1.11
>>
>> This is an old version from 2013. Try a more recent gold version first.
>>
>> --
>> Markus
>
>
>
> --
> Matt



-- 
Matt