Is regs_ever_live valid in prologue? (SPARC quirk?)

[David S. Miller]

   From: Jim Wilson <wilson@redhat.com>
   Date: 29 Apr 2002 18:53:19 -0400

   Someone would have to debug gcc to figure out why %i1 is being used.
   
We don't know if a function is truly leaf until near the
end, so we use %i[0-5] instead of %o[0-5] until the very
end, then we renumber the ins to outs.

Actually, this is too obvious to be the issue.
What is the problem actually?