https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94743
--- Comment #6 from Christophe Lyon <clyon at gcc dot gnu.org> --- If we consider the initial testcase, it doesn't clobber any FP register directly, but the compiler inserts a call to memcpy which does. So IIUC your 1st suggestion, it would mean: - save no FP register in the IRQ handler - call a libgcc routine to save all FP registers+status registers (this routine would have to decide about d16 vs d32 at runtime, unless we can rely on multilibs -- it would mean defining mandatory d16 and d32 libgcc multilibs...) Hence I like your simpler suggestion :-) But I think we should help the user diagnose potential problems: - maybe issue a warning when compiling an IRQ handler without -mgeneral-regs-only. That might break some packages, but would force them to check their code - also emit a warning when calling a function defined in another unit (but we should recurse) However this does not help if the compiler inserts a call to memcpy which happens to be using FPU code: the user would get a warning, but how could he solve it? Avoid implicit use of memcpy?
