[Bug target/81879] Bad compilation of small program if LTO is used

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81879

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2019-02-24
                 CC|                            |marxin at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #4 from Martin Liška <marxin at gcc dot gnu.org> ---
Confirmed. I can confirm that the difference in resolution file is the problem:

750 6dacea834fb099d1 PREVAILING_DEF_IRONLY _ZNKSt5ctypeIcE8do_widenEc
vs.
750 1b64a3a32ab1e36a PREEMPTED_REG _ZNKSt5ctypeIcE8do_widenEc

Note that on a native x86_64-linux-gnu system, the resolution is also
PREVAILING_DEF_IRONLY with -static option.

It's also visible with:

x86_64-w64-mingw32-nm --plugin
/usr/lib64/gcc/x86_64-w64-mingw32/8.2.0/liblto_plugin.so simpler.o | grep
do_widen
00000000 T _ZNKSt5ctypeIcE8do_widenEc

while on a native linux system:
nm s2.o | grep do_widen
00000000 W _ZNKSt5ctypeIcE8do_widenEc

T == The symbol is in the text (code) section.
W == The symbol is a weak object.