https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90133
--- Comment #5 from Dominique d'Humieres <dominiq at lps dot ens.fr> --- > Sure, I understand regresion, but perhaps I don't understand what you mean > by "has been backported to GCC6". The patch which caused the GCC7 regression has then been applied to GCC6: 6.0.0 works, but not 6.5.0.