https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94743
--- Comment #5 from Richard Earnshaw <rearnsha at gcc dot gnu.org> --- This is made more complex due to the fact that the existence of the top 16 D registers depends on the hardware you have, so saving them might require a d32 variant of the ISA, but we can't (quickly) tell in an interrupt context whether or not we have that. It only matters in reality if the interrupt routine calls a function in another translation unit where we can't see what FP registers might be needed. Also, it's not just the registers that need to be saved. The floating point status registers also need to be saved and restored. My initial thoughts are along the lines of... Only try to save FP registers that this function directly clobbers. Provide libgcc routines to save/restore the FP context. Or we could say simply: interrupt routines should be compiled as if with -mgeneral-regs-only and if they want to call some routine that uses FP then they must take it upon themselves to save and restore the FP context.
