[rtlopt] update profile properly for runtime unrolling

[rtlopt] update profile properly for runtime unrolling

[Jan Hubicka]

Hi,
minor problem I guess, but we were updating the profile incorrectly
here.
Sat Oct 26 02:16:39 CEST 2002  Jan Hubicka  <jh@suse.cz>
	* unroll.c (unroll_loop_runtime_iterations):  Compute edge probabilities properly.
*** loop-unroll.c.old1	Sat Oct 26 01:44:17 2002
--- loop-unroll.c	Sat Oct 26 02:09:08 2002
*************** unroll_loop_runtime_iterations (loops, l
*** 356,371 ****
  
    for (i = 0; i < n_peel; i++)
      {
        start_sequence ();
        niter = expand_simple_binop (GET_MODE (desc->var), MINUS,
  				   niter, const1_rtx,
  				   NULL_RTX, 0, OPTAB_LIB_WIDEN);
        if (i || !skip_first_test)
  	{
  	  do_compare_rtx_and_jump (copy_rtx (niter), const0_rtx, EQ, 0,
  		GET_MODE (desc->var), NULL_RTX, NULL_RTX,
  		loop_beg_label);
! 	  JUMP_LABEL (get_last_insn ()) = loop_beg_label;
  	  LABEL_NUSES (loop_beg_label)++;
  	}
        branch_code = get_insns ();
--- 356,378 ----
  
    for (i = 0; i < n_peel; i++)
      {
+       edge e;
        start_sequence ();
        niter = expand_simple_binop (GET_MODE (desc->var), MINUS,
  				   niter, const1_rtx,
  				   NULL_RTX, 0, OPTAB_LIB_WIDEN);
        if (i || !skip_first_test)
  	{
+ 	  rtx jump;
  	  do_compare_rtx_and_jump (copy_rtx (niter), const0_rtx, EQ, 0,
  		GET_MODE (desc->var), NULL_RTX, NULL_RTX,
  		loop_beg_label);
! 	  jump = get_last_insn ();
! 	  JUMP_LABEL (jump) = loop_beg_label;
! 	  REG_NOTES (jump)
! 	    = gen_rtx_EXPR_LIST (REG_BR_PROB,
! 				 GEN_INT (REG_BR_PROB_BASE / (n_peel - i + 1)), REG_NOTES (jump));
! 	
  	  LABEL_NUSES (loop_beg_label)++;
  	}
        branch_code = get_insns ();
*************** unroll_loop_runtime_iterations (loops, l
*** 374,379 ****
--- 381,391 ----
        preheader =
  	loop_split_edge_with (loop_preheader_edge (loop), branch_code, loops);
  
+       e = loop_preheader_edge (loop);
+       /* Now lower the probablity of the edge as the other edge will handle it.  */
+       e->probability = REG_BR_PROB_BASE - (REG_BR_PROB_BASE / (n_peel - i + 1));
+       e->count = e->count * e->probability / REG_BR_PROB_BASE;
+ 
        if (i || !skip_first_test)
  	make_edge (preheader, fake, 0);