https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106943
--- Comment #22 from Alexander Monakov <amonakov at gcc dot gnu.org> --- (In reply to Jan Hubicka from comment #19) > It would be really nice to have the ranger bug fixed. Since lifetime > DSE is all handled in C++ FE there is no good reason why it should not > work to LTO togehter objects compiled with the flag and without... Wait. There's absolutely no connection between lifetime-dse and the ranger issue uncovered by -flto-partition=1to1. Selective -fno-lifetime-dse surely works, as you said it's fully handled by the front-end. I was just saying that applying -fno-lifetime-dse to User.cpp is insufficient because problematic codegen happens in other translation units (where objects of class User are constructed). Fully agreed that fixing the ranger bug would be nice regardless. > llvm is really nice benchmark for LTO and PGO, so it would be nice if it > was not fragile and built with -O3 -flto. In my testing GCC produced > binary with LTO+PGO is a lot smaller. It seems to also generate code > faster but parsing is bit slower, which I think may be related to > -fstrict-aliasing. Makes sense I guess.
