[Bug libstdc++/60621] std::vector::emplace_back generates massively more code than push_back

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60621

--- Comment #1 from Marc Glisse <glisse at gcc dot gnu.org> ---
Some things that help:
-fabi-version=0
-fwhole-program (so it knows emplace_back won't be used anywhere else, and it
can inline it and remove the unneeded paths)