https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63603
--- Comment #3 from Tobias Burnus <burnus at gcc dot gnu.org> --- (In reply to Tobias Burnus from comment #2) > COLLECT_GCC_OPTIONS='-v' '-fno-use-linker-plugin' '-fno-lto' > '-mtune=generic' '-march=x86-64' > [...]/collect2 [...] I haven't shown it, but the collect2 arguments doesn't contain the -fno-lto, only COLLECT_GCC_OPTIONS has it. And in collect2.c's main(), there is a check for else if (!strncmp (argv[i], "-fno-lto", 8)) lto_mode = LTO_MODE_NONE; but that only operates on argv and not on COLLECT_GCC_OPTIONS.