https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82221
--- Comment #15 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Josh Poimboeuf from comment #14)
> (In reply to H.J. Lu from comment #13)
> > (In reply to Josh Poimboeuf from comment #12)
> > > I would like to clarify that most of the time, when we use "sp" in the
> > > clobbers list, the stack does *not* need to be realigned. And in those
> >
> > Yes, stack alignment may be needed due to:
> >
> > typedef struct {
> > u64 __attribute__((aligned(8))) counter;
> > } atomic64_t;
> >
> > with -mpreferred-stack-boundary=2.
>
> Yes, in the above example that is true. However there are many more cases
> in the kernel where we want to use the "sp" clobbers, where stack alignment
> is not needed.
DRAP is used only when stack realignment may be needed. If the code doesn't
need more 4 byte alignment on stack, you won't run into this issue at all.
