https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79929
--- Comment #21 from Martin Sebor <msebor at gcc dot gnu.org> --- The rtl.c error was discussed in the context of some other bug having to do with profiledbootstrap failure (I can't find the bug now). If I recall, it's due to the same signed <-> unsigned conversion issue as a number of other warnings of this kind, i.e., rtvec_alloc taking a signed int argument that's being converted to size_t. Besides configuring with the --disable-werror recommended for profiledbootstrap, adding a gcc_assert(n >= 0) fixed it. Strangely, though, changing the function's argument to unsigned seemed to tickle some latent bug somewhere and caused GCC to crash during bootstrap. I never investigated why.
