[PATCH] Use reversed_comparison_code in sched-deps.c

[Richard Earnshaw <rearnsha at buzzard dot freeserve dot co dot uk>]

Sched-deps.c has to handle comparison operations that might involve 
floating point operands.  It's therefore undesirable for this to be using 
reverse_condition, since that just returns UNKNOWN in some circumstances 
and the incorrect (integer) reversal in others.  This patch fixes both 
instances where this can happen by using reversed_comparison_code, which 
does know how to do the right thing (in one case we don't have an insn to 
pass, but that shouldn't affect correctness, just whether or not we can do 
an optimization, and even then only on ports that don't define 
REVERSE_CONDITION).

Secondly this patch fixes what must have been a long-standing bug in 
get_condition (the version in this file, not the identically named one in 
the loop optimizer), where we looked in the SET_DEST of a jump for an 
IF_THEN_ELSE when we should have been looking in the SET_SRC.  In fixing 
this I've made use of the various support functions in jump.c to make the 
code more general.

Tested on i386-netbsdelf2 and arm-linux-gnu with no regressions.

2004-08-29  Richard Earnshaw  <rearnsha@arm.com>

	* sched-deps.c (get_condition): Rewrite using jump support functions.
	Use reversed_comparison_code.
	(conditions_mutex_p): Use reversed_comparison_code.


Index: sched-deps.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/sched-deps.c,v
retrieving revision 1.76
diff -p -p -r1.76 sched-deps.c
*** sched-deps.c	9 Jul 2004 03:29:35 -0000	1.76
--- sched-deps.c	29 Aug 2004 20:30:03 -0000
*************** get_condition (rtx insn)
*** 145,167 ****
  
    if (pat == 0)
      return 0;
    if (GET_CODE (pat) == COND_EXEC)
      return COND_EXEC_TEST (pat);
!   if (!JUMP_P (insn))
!     return 0;
!   if (GET_CODE (pat) != SET || SET_SRC (pat) != pc_rtx)
!     return 0;
!   if (GET_CODE (SET_DEST (pat)) != IF_THEN_ELSE)
      return 0;
!   pat = SET_DEST (pat);
!   cond = XEXP (pat, 0);
!   if (GET_CODE (XEXP (cond, 1)) == LABEL_REF
!       && XEXP (cond, 2) == pc_rtx)
      return cond;
!   else if (GET_CODE (XEXP (cond, 2)) == LABEL_REF
! 	   && XEXP (cond, 1) == pc_rtx)
!     return gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)), GET_MODE (cond),
! 			   XEXP (cond, 0), XEXP (cond, 1));
    else
      return 0;
  }
--- 145,169 ----
  
    if (pat == 0)
      return 0;
+ 
    if (GET_CODE (pat) == COND_EXEC)
      return COND_EXEC_TEST (pat);
! 
!   if (!any_condjump_p (insn) || !onlyjump_p (insn))
      return 0;
! 
!   cond = XEXP (SET_SRC (pc_set (insn)), 0);
!   if (XEXP (cond, 2) == pc_rtx)
      return cond;
!   else if (XEXP (cond, 1) == pc_rtx)
!     {
!       enum rtx_code revcode = reversed_comparison_code (cond, insn);
! 
!       if (revcode == UNKNOWN)
! 	return 0;
!       return gen_rtx_fmt_ee (revcode, GET_MODE (cond), XEXP (cond, 0),
! 			     XEXP (cond, 1));
!     }
    else
      return 0;
  }
*************** conditions_mutex_p (rtx cond1, rtx cond2
*** 173,179 ****
  {
    if (COMPARISON_P (cond1)
        && COMPARISON_P (cond2)
!       && GET_CODE (cond1) == reverse_condition (GET_CODE (cond2))
        && XEXP (cond1, 0) == XEXP (cond2, 0)
        && XEXP (cond1, 1) == XEXP (cond2, 1))
      return 1;
--- 175,181 ----
  {
    if (COMPARISON_P (cond1)
        && COMPARISON_P (cond2)
!       && GET_CODE (cond1) == reversed_comparison_code (cond2, NULL)
        && XEXP (cond1, 0) == XEXP (cond2, 0)
        && XEXP (cond1, 1) == XEXP (cond2, 1))
      return 1;