Re: Scheduling fix (fixes gcc.c-torture/execute/980506-1.c on ppc)

[Jeffrey A Law <law at cygnus dot com>]

  Geoff:
  > >Now, basic block 2 has two exits.  One exit goes back to basic block
  > >1.  The other goes off the edge of the procedure.  Unfortunately,
  > >haifa only notices the first one, because the second exit doesn't go
  > >to any basic block, and thinks basic block 2 has only one exit; so the
  > >branch must be taken with 100% probability:
Right.  But this is a total red herring.  The problem is/was elsewhere.

  > Tue Aug 18 10:32:11 1998  Jeffrey A Law  (law@cygnus.com)
  > 
  >         * haifa-sched.c (sched_analyze): Put all JUMP_INSNs on the last
  >         pending memory flush list.
  > 
  > This patch alone fixed 980506-1.c for me and others. Doesn't it fix all
  > possible cases?
Catherine's patch should have fixed 980506-1.c completely.

The core problem was we should not be moving memory references past
jump instructions at all.  It would be nice one day to fix up the
code for speculative load/store scheduling though since several new
architectures have some kind of speculative load/store support.

jeff