[patch] Fix bug in variable-tracking

[Josef Zlomek]

> I think it would be better if you passed an extra argument to
> variable_different_p.  This makes it clearer what the patch is doing.
> 
> There is also an efficiency problem with your patch.  Because of the way
> it is written, variable_part_different_p must always be called twice
> with the args reversed.  The new check you added however is always the
> same regardless of the argument order.  Hence it makes more sense to put
> it in variable_different_p than in variable_part_different_p, so that we
> only perform the check once.

I have fixed the patch according to your comments.

Bootstrapped/regtested x86_64 (ia64 in progress).
OK if it passes tests on ia64?

Josef

2004-04-27  Josef Zlomek  <zlomekj@suse.cz>

	* var-tracking.c (variable_different_p): Add a parameter
	compare_current_location, compare current location of variable parts
	if it is true.
	(dataflow_set_different_1): Pass compare_current_location == false.
	(dataflow_set_different_2): Pass compare_current_location == false.
	(emit_notes_for_differences_1): Pass compare_current_location == true.

Index: var-tracking.c
===================================================================
RCS file: /cvs/gcc-cvs/gcc/gcc/var-tracking.c,v
retrieving revision 2.15
diff -c -p -c -3 -p -r2.15 var-tracking.c
*** var-tracking.c	22 Apr 2004 12:16:33 -0000	2.15
--- var-tracking.c	27 Apr 2004 14:28:56 -0000
*************** static int variable_union_info_cmp_pos (
*** 304,310 ****
  static int variable_union (void **, void *);
  static void dataflow_set_union (dataflow_set *, dataflow_set *);
  static bool variable_part_different_p (variable_part *, variable_part *);
! static bool variable_different_p (variable, variable);
  static int dataflow_set_different_1 (void **, void *);
  static int dataflow_set_different_2 (void **, void *);
  static bool dataflow_set_different (dataflow_set *, dataflow_set *);
--- 304,310 ----
  static int variable_union (void **, void *);
  static void dataflow_set_union (dataflow_set *, dataflow_set *);
  static bool variable_part_different_p (variable_part *, variable_part *);
! static bool variable_different_p (variable, variable, bool);
  static int dataflow_set_different_1 (void **, void *);
  static int dataflow_set_different_2 (void **, void *);
  static bool dataflow_set_different (dataflow_set *, dataflow_set *);
*************** variable_part_different_p (variable_part
*** 1260,1271 ****
    return false;
  }
  
! /* Return true if variables VAR1 and VAR2 are different (only the first
!    location in the list of locations is checked for each offset,
!    i.e. when true is returned a note should be emitted).  */
  
  static bool
! variable_different_p (variable var1, variable var2)
  {
    int i;
  
--- 1260,1272 ----
    return false;
  }
  
! /* Return true if variables VAR1 and VAR2 are different.
!    If COMPARE_CURRENT_LOCATION is true compare also the cur_loc of each
!    variable part.  */
  
  static bool
! variable_different_p (variable var1, variable var2,
! 		      bool compare_current_location)
  {
    int i;
  
*************** variable_different_p (variable var1, var
*** 1279,1284 ****
--- 1280,1295 ----
      {
        if (var1->var_part[i].offset != var2->var_part[i].offset)
  	return true;
+       if (compare_current_location)
+ 	{
+ 	  if (!((GET_CODE (var1->var_part[i].cur_loc) == REG
+ 		 && GET_CODE (var2->var_part[i].cur_loc) == REG
+ 		 && (REGNO (var1->var_part[i].cur_loc)
+ 		     == REGNO (var2->var_part[i].cur_loc)))
+ 		|| rtx_equal_p (var1->var_part[i].cur_loc,
+ 				var2->var_part[i].cur_loc)))
+ 	    return true;
+ 	}
        if (variable_part_different_p (&var1->var_part[i], &var2->var_part[i]))
  	return true;
        if (variable_part_different_p (&var2->var_part[i], &var1->var_part[i]))
*************** dataflow_set_different_1 (void **slot, v
*** 1307,1313 ****
        return 0;
      }
  
!   if (variable_different_p (var1, var2))
      {
        dataflow_set_different_value = true;
  
--- 1318,1324 ----
        return 0;
      }
  
!   if (variable_different_p (var1, var2, false))
      {
        dataflow_set_different_value = true;
  
*************** dataflow_set_different_2 (void **slot, v
*** 1342,1348 ****
  #ifdef ENABLE_CHECKING
    /* If both variables are defined they have been already checked for
       equivalence.  */
!   if (variable_different_p (var1, var2))
      abort ();
  #endif
  
--- 1353,1359 ----
  #ifdef ENABLE_CHECKING
    /* If both variables are defined they have been already checked for
       equivalence.  */
!   if (variable_different_p (var1, var2, false))
      abort ();
  #endif
  
*************** emit_notes_for_differences_1 (void **slo
*** 2286,2292 ****
        empty_var->n_var_parts = 0;
        variable_was_changed (empty_var, NULL);
      }
!   else if (variable_different_p (old_var, new_var))
      {
        variable_was_changed (new_var, NULL);
      }
--- 2297,2303 ----
        empty_var->n_var_parts = 0;
        variable_was_changed (empty_var, NULL);
      }
!   else if (variable_different_p (old_var, new_var, true))
      {
        variable_was_changed (new_var, NULL);
      }