updating edge profiling

[Qiong Cai]

Hi,

I met a problem of updating edge profiling when the CFG
is implicitly changed.

For example(maybe silly), x = a - b is changed to the following
codes:
  if ( a == b )
    x = 0;   // 10000 times
  else	    // 0 time
      x = a - b;

we may implement this as:

  start_sequence()
  ...
  do_compare_rtx_jump (...)
  emit_label (...)
  emit_move_insn (...)
  ...
  seq = get_insns ();
  end_sequence()
  rebuild_jump_lables ()
  commit_edge_insertsion()
  
However, it seems there's no place to update edge profiling 
information in the above codes, even though we know the branch
probabilities.

The same problem also exists in the value-profile.c, because it 
changed the CFG too.

Is there any  way to update edge profile? Thanks.


Qiong