https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100464
--- Comment #14 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Yes. You'll get an error, like: error: t.c: ‘-fcompare-debug’ failure (length) or error: t.c: ‘-fcompare-debug’ failure Under the hood, the driver invokes the compiler once with the options you've given plus -fdump-final-insns=sometempfile1 and then also with the options you've given plus -gtoggle -fcompare-debug-second -fdump-final-insns=sometempfile2 (and will throw away stdout/stderr from the compiler). The (length) failure means sometempfile1 and sometempfile2 have different lengths, while the other error mean they have the same length, but their content differs.
