Fix 991213-1.c testcase abort on Sparc

[Jeffrey A Law]

  In message < 199912161052.CAA02032@pizda.ninka.net >you write:
  >    Date: Thu, 16 Dec 1999 00:43:49 -0700
  >    From: Jeffrey A Law <law@cygnus.com>
  > 
  >      > You are probably right about the illegality of this situation.
  >      > But let's make sure we agree on that first.  If it is true next
  >      > we can figure out why these got left behind and fix the code
  >      > which did it, then revert my change.
  > 
  >    I'm pretty sure we're not supposed to have CONCATs in the insn chain.
  > 
  > Ok, so the fix should be to make this clobber emitting part of
  > emit_move_*() emit the clobbers of the components of a CONCAT
  > instead.
Hmmm.  I just realized an interesting problem.  The whole point of the clobber
is to show the entire value is being written.  I don't see a good way to do
that in that code.  ie, we want to emit a single CLOBBER insn which stomps on
the entire value.  We can't do it in little hunks.

Hmmmm.  Let's think a little more before you try to kill the CONCAT from the
insn stream.

jeff