[tree-ssa] Make tsi insert iterators handle chains of COMPOUND_EXPRs

[Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>]

Hello,

this patch improves tsi_link_before and tsi_link_after so that if
the statement you link in is right-recursive chain of COMPOUND_EXPRs,
rationalize_compound_expr does not have to be called.

This enables to remove creation of BIND_EXPR from replace_stmt.

Zdenek

	* tree-iterator.h (enum tsi_iterator_update): Add TSI_CHAIN_END.
	* tree.c (tsi_link_before, tsi_link_after): Handle insertion of
	COMPOUND_EXPR chains.

Index: tree-iterator.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/Attic/tree-iterator.h,v
retrieving revision 1.1.2.7
diff -c -3 -p -r1.1.2.7 tree-iterator.h
*** tree-iterator.h	15 Jul 2003 03:13:40 -0000	1.1.2.7
--- tree-iterator.h	28 Aug 2003 19:46:28 -0000
*************** typedef tree tree_stmt_anchor;
*** 149,155 ****
  enum tsi_iterator_update
  {
    TSI_NEW_STMT,
!   TSI_SAME_STMT
  };
  
  void tsi_link_before (tree_stmt_iterator *, tree, enum tsi_iterator_update);
--- 149,156 ----
  enum tsi_iterator_update
  {
    TSI_NEW_STMT,
!   TSI_SAME_STMT,
!   TSI_CHAIN_END
  };
  
  void tsi_link_before (tree_stmt_iterator *, tree, enum tsi_iterator_update);
Index: tree.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree.c,v
retrieving revision 1.263.2.48
diff -c -3 -p -r1.263.2.48 tree.c
*** tree.c	21 Aug 2003 07:44:57 -0000	1.263.2.48
--- tree.c	28 Aug 2003 19:46:32 -0000
*************** build_empty_stmt (void)
*** 5113,5132 ****
  void
  tsi_link_before (tree_stmt_iterator *i, tree t, enum tsi_iterator_update mode)
  {
!   tree ce;
  
    /* Build a new CE which points to the current node.  */
!   ce = build (COMPOUND_EXPR, void_type_node, t, *(i->tp));
  
    /* Make the parent pointer point to this new node.  At this point, the
       iterator will be pointing to the new node we just inserted.  */
!   *(i->tp) = ce;
  
    /* Update the iterator to points to the address of the next ptr in our new 
       node, which is the current stmt again.  */
    if (mode == TSI_SAME_STMT)
!     i->tp = &(TREE_OPERAND (*(i->tp), 1));
! 
  }
  
  /* Links a stmt after the current stmt.  */
--- 5113,5138 ----
  void
  tsi_link_before (tree_stmt_iterator *i, tree t, enum tsi_iterator_update mode)
  {
!   tree *last;
! 
!   for (last = &t;
!        TREE_CODE (*last) == COMPOUND_EXPR;
!        last = &TREE_OPERAND (*last, 1))
!     continue;
  
    /* Build a new CE which points to the current node.  */
!  *last = build (COMPOUND_EXPR, void_type_node, *last, *(i->tp));
  
    /* Make the parent pointer point to this new node.  At this point, the
       iterator will be pointing to the new node we just inserted.  */
!   *(i->tp) = t;
  
    /* Update the iterator to points to the address of the next ptr in our new 
       node, which is the current stmt again.  */
    if (mode == TSI_SAME_STMT)
!     i->tp = &(TREE_OPERAND (*last, 1));
!   else if (mode == TSI_NEW_STMT)
!     i->tp = last != &t ? last : i->tp;
  }
  
  /* Links a stmt after the current stmt.  */
*************** tsi_link_after (tree_stmt_iterator *i, t
*** 5136,5141 ****
--- 5142,5148 ----
  {
    tree ce;
    tree next;
+   tree *last;
  
    /* If this node isnt a COMPUND_EXPR, we need to insert a CE node. */
    if (TREE_CODE (*(i->tp)) != COMPOUND_EXPR)
*************** tsi_link_after (tree_stmt_iterator *i, t
*** 5150,5172 ****
        /* Change new iterator to point to the new stmt.  */
        if (mode == TSI_NEW_STMT)
  	i->tp = &(TREE_OPERAND (ce, 1));
      }
    else
      {
!       next  = TREE_OPERAND (*(i->tp), 1);
  
!       /* Create a new node with the same 'next' link as the current one.  */
!       ce = build (COMPOUND_EXPR, void_type_node, t, next);
  
!       /* Make the current one's 'next' link point to our new stmt.  */
!       TREE_OPERAND (*(i->tp), 1) = ce;
  
        /* Update the iterator to the new stmt.  */
        if (mode == TSI_NEW_STMT)
  	i->tp = &(TREE_OPERAND (*(i->tp), 1));
      }
- 
-   
  }
  
  /* Remove a stmt from the tree list.  The iterator is updated to point to
--- 5157,5185 ----
        /* Change new iterator to point to the new stmt.  */
        if (mode == TSI_NEW_STMT)
  	i->tp = &(TREE_OPERAND (ce, 1));
+       else if (mode == TSI_CHAIN_END)
+ 	while (TREE_CODE (*i->tp) == COMPOUND_EXPR)
+ 	  i->tp = &(TREE_OPERAND (*i->tp, 1));
      }
    else
      {
!       for (last = &t;
! 	   TREE_CODE (*last) == COMPOUND_EXPR;
! 	   last = &TREE_OPERAND (*last, 1))
! 	continue;
  
!       next = TREE_OPERAND (*(i->tp), 1);
  
!       /* Create a new node with the same 'next' link as the current one.  */
!       *last = build (COMPOUND_EXPR, void_type_node, *last, next);
!       TREE_OPERAND (*(i->tp), 1) = t;
  
        /* Update the iterator to the new stmt.  */
        if (mode == TSI_NEW_STMT)
  	i->tp = &(TREE_OPERAND (*(i->tp), 1));
+       else if (mode == TSI_CHAIN_END)
+ 	i->tp = last != &t ? last : &(TREE_OPERAND (*(i->tp), 1));
      }
  }
  
  /* Remove a stmt from the tree list.  The iterator is updated to point to