[Bug lto/45375] [meta-bug] Issues with building Mozilla with LTO

[hubicka at ucw dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45375

--- Comment #205 from Jan Hubicka <hubicka at ucw dot cz> ---
I was looking into this recently, too.  Curiously enough, for me clang+LTO was
winning
but comparing the symbols it seemed that the confiugre scripts picked bit more
features
at GCC side.  I looked briefly on the differences and we can optimize out more
vtables
which I have patch for pending for next stage1 and optimize out write only
global vars.
Still the differences may be worth further investigation - clang seems to
produce noticeably
fewer external relocations, too. This seems like a ABI bug at clang side
though.

What I use for my firefox builds is --param inline-unit-growth=5.  Our -O3
seems bit
of overkill for applicatin of fize of Firefox...

Honza