I think it would be mildly clearer to pass the mode (rather than the
number of registers) to kill_value_regno, and let it do the
hard_regno_regs thing itself; that makes the function a little more
abstract. So, please make that change as well.
I can't do that. The problem is that we don't know what the basic
mode of the register is from the call in copyprop_hardreg_forward_1
(spelling?). We just know that we want to clobber this register, and
any values in earlier registers which overlap it.
Still OK without that change?