https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70704
--- Comment #45 from Jakub Jelinek <jakub at gcc dot gnu.org> --- I don't think M4 env var should make a difference in this case, in the release tarballs the gengtype-lex.c file is already built (on x86_64-linux) and nothing should be changing that. That said, I've managed to reproduce the miscompare on build/ggc-none.o as an example of very small source file, even with -g0. But it looks really weird. First of all, it seems that the system g++ 4.8 and g++ 6.1-rc2 is probably ABI incompatible, at least my attempts to mix stage1 and stage2 objects into the same binary failed miserably. I've rebuilt stage2-gcc/ cc1plus with CXXFLAGS='-g -O0', thus most if not all *.o files linked into it should be (like in stage1) built without optimizations, and still see the differences. Trying to find out where the differences start now using parallel gdb sessions.
