cause of all the mainline Sparc regressions

[David S. Miller]

   From: Jan Hubicka <jh@suse.cz>
   Date: Thu, 23 May 2002 16:49:11 +0200

   > But if you delete unreachable blocks, shouldn't you optimize the
   > CFG in the hopes that EH will end up doing less work?
   
   I think EH ends up with less work only when some receivers become
   unreachable and this can happen only from unreachable/dead code removal,
   I guess it does not happen by the optimization cleanup_cfg does except
   for code removal. We can save some overhead then.

What if the beginning of EH receiver is a simplejump or a cross jump
to some other place?

Isn't this a similar reason why sibcall does a CFG cleanup too?  My
thinking is that sibcall wants the cfg cleanup done so that the "after
this call we jump next to epilogue or we tail recurse" condition is
clearer.