[PATCH, committed] PowerPC jump and loop alignment

[David Edelsohn]

	POWER4 and POWER5 show better performance when branching to
aligned addresses, which help instruction fetch.

David

	* config/rs6000/rs6000.c (rs6000_override_options): Increase
	maximum skip to 15.  Set function alignment, jump alignment, and
	loop alignment to 16 for processors that form dispatch groups.
	(rs6000_rtx_costs): outer_code is used.

Index: rs6000.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/rs6000/rs6000.c,v
retrieving revision 1.702
diff -c -p -r1.702 rs6000.c
*** rs6000.c	26 Aug 2004 17:20:16 -0000	1.702
--- rs6000.c	27 Aug 2004 17:46:47 -0000
*************** rs6000_override_options (const char *def
*** 1429,1437 ****
        targetm.asm_out.unaligned_op.di = NULL;
      }
  
!   /* Set maximum branch target alignment at two instructions, eight bytes.  */
!   align_jumps_max_skip = 8;
!   align_loops_max_skip = 8;
  
    /* Arrange to save and restore machine status around nested functions.  */
    init_machine_status = rs6000_init_machine_status;
--- 1429,1451 ----
        targetm.asm_out.unaligned_op.di = NULL;
      }
  
!   /* Set branch target alignment, if not optimizing for size.  */
!   if (!optimize_size)
!     {
!       if (rs6000_sched_groups)
! 	{
! 	  if (align_functions <= 0)
! 	    align_functions = 16;
! 	  if (align_jumps <= 0)
! 	    align_jumps = 16;
! 	  if (align_loops <= 0)
! 	    align_loops = 16;
! 	}
!       if (align_jumps_max_skip <= 0)
! 	align_jumps_max_skip = 15;
!       if (align_loops_max_skip <= 0)
! 	align_loops_max_skip = 15;
!     }
  
    /* Arrange to save and restore machine status around nested functions.  */
    init_machine_status = rs6000_init_machine_status;
*************** rs6000_binds_local_p (tree decl)
*** 17070,17077 ****
     scanned.  In either case, *TOTAL contains the cost result.  */
  
  static bool
! rs6000_rtx_costs (rtx x, int code, int outer_code ATTRIBUTE_UNUSED,
! 		  int *total)
  {
    enum machine_mode mode = GET_MODE (x);
  
--- 17084,17090 ----
     scanned.  In either case, *TOTAL contains the cost result.  */
  
  static bool
! rs6000_rtx_costs (rtx x, int code, int outer_code, int *total)
  {
    enum machine_mode mode = GET_MODE (x);