https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79407
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution|--- |INVALID --- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- Quote: "It is an error to use this flag with the frame pointer or stack pointer. Use of this flag for other registers that have fixed pervasive roles in the machine's execution model produces disastrous results. A different sort of disaster results from the use of this flag for a register in which function values may be returned. " so you get that different sort of disaster results.