try_split lossage

[Jeffrey A Law]

  In message <199906161751.NAA13265@jwlab.FEITH.COM>you write:
  > An insn may have various characteristics (such as CONST_CALL_P,
  > INSN_ANNULLED_BRANCH_P, INSN_FROM_TARGET_P, RTX_FRAME_RELATED_P)
  > which affect code generation.  try_split attempts to replace the
  > insn with other insn(s).  What isn't clear to me is how the new
  > insn(s) inherit the characteristics of the insn which is being
  > replaced.  
  > 
  > Should try_split either abort or avoid splitting insns which
  > have any of these characteristics?
Well, losing a CONST_CALL_P or RTX_FRAME_RELATED_P shouldn't cause any serious
problems.

However, losing the ANNULLED_BRANCH_P or INSN_FROM_TARGET_P could cause
problems.  But we shouldn't get insns with those bits set because they
would have already been split by the delay slot scheduler.

jeff