https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81241
--- Comment #2 from Rich Townsend <townsend at astro dot wisc.edu> --- Aha, given that MESA is multithreaded, this may well be linked to this issue: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78387 Certainly, running with just 1 thread seems to make things behave.
