https://gcc.gnu.org/bugzilla/show_bug.cgi?id=74585
--- Comment #17 from Segher Boessenkool <segher at gcc dot gnu.org> --- The stack is always in memory, AFAIK :-) Do we have any targets where it is not? Do we have any targets where BLKmode is not always in memory? That is something that should be documented btw :-) Anyway, if the Gimple passes assume this to be true always, all optimisations that depend on the contrary will have to stay in RTL only, not the direction that people seem to want to move in :-)