Repair CONTAINS_PLACEHOLDER_P

[Eric Botcazou <ebotcazou at adacore dot com>]

Hi,

The following testcase ICEs in the gimplifier with GCC 4.x:

procedure p is

  type S is (E1, E2);
  for S use (E1=>1, E2=>2);

  type A is array (S range <>) of Natural;

  type R(D : S) is
    record
      C : A (E1..D);
    end record;

begin
  null;
end;


The CONTAINS_PLACEHOLDER_P predicate returns false for any CALL_EXPR tree with 
GCC 4.x.  The story is as follows: contains_placeholder_p in 3.4 reads

    case '1':
    case '2':  case '<':
    case 'e':
      switch (code)
        {
        case COMPOUND_EXPR:
          /* Ignoring the first operand isn't quite right, but works best.  */
          return CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1));

        case RTL_EXPR:
        case CONSTRUCTOR:
          return 0;

        case COND_EXPR:
          return (CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 0))
                  || CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1))
                  || CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 2)));

        case SAVE_EXPR:
          /* If we already know this doesn't have a placeholder, don't
             check again.  */
          if (SAVE_EXPR_NOPLACEHOLDER (exp) || SAVE_EXPR_RTL (exp) != 0)
            return 0;

          SAVE_EXPR_NOPLACEHOLDER (exp) = 1;
          result = CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 0));
          if (result)
            SAVE_EXPR_NOPLACEHOLDER (exp) = 0;

          return result;

        case CALL_EXPR:
          return CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1));

        default:
          break;
        }

      switch (TREE_CODE_LENGTH (code))
        {
        case 1:
          return CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 0));
        case 2:
          return (CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 0))
                  || CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1)));
        default:
          return 0;
        }


Richard removed the CALL_EXPR case as part of:

2004-03-21  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>

	* alias.c (get_alias_set): Remove handling of PLACEHOLDER_EXPR.
	* emit-rtl.c (component_ref_for_mem_expr): Likewise.
	(set_mem_attributes_minus_bitpos): Call SUBSTITUTE_PLACEHOLDER_IN_EXPR.
	* explow.c (expr_size): Likewise.
	* expr.h (placeholder_list, find_placeholder): Deleted.
	* expr.c (store_constructor): Likewise.
	(get_inner_reference): Likewise.  Also don't call find_placeholder.
	(placeholder_list, find_placeholder): Deleted.
	(is_aligning_offset): Don't handle WITH_RECORD_EXPR, PLACEHOLDER_EXPR.
	(expand_expr_real, cases PLACEHOLDER_EXPR, WITH_RECORD_EXPR): Likewise.
	(highest_pow2_factor, case WITH_RECORD_EXPR): Remove.
	* dojump.c (do_jump, case WITH_RECORD_EXPR): Likewise.	
	* dwarf2out.c (loc_descriptor_from_tree, case WITH_RECORD_EXPR):
	Likewise.
	* fold-const.c (invert_truthvalue, case WITH_RECORD_EXPR): Likewise.
	(extract_muldiv, case WITH_RECORD_EXPR): Likewise.
	* tree.c (expr_align, case WITH_RECORD_EXPR): Likewise.
	(contains_placeholder_p): Don't handle WITH_RECORD_EXPR.
	Clean up by using first_rtl_op.
	(substitute_in_expr): Use SUBSTITUTE_IN_EXPR for recursive call.
	(substitute_placeholder_in_expr): New function.
	* tree.def (WITH_RECORD_EXPR): Deleted.
	* tree.h (SUBSTITUTE_IN_EXPR, SUBSTITUTE_PLACEHOLDER_IN_EXPR): New.
	(substitute_placeholder_in_expr): New.

because it was partially redundant with the subsequent "2" case.

Then the big Tree-SSA merge occured 2 months later and the TREE_CODE_LENGTH of 
CALL_EXPR was bumped to 3.  The patch restores the 3.4 behavior and has been 
bootstrapped/regtested on x86_64-suse-linux.  Applied to mainline as obvious.

Mark, may I apply it to the 4.0 branch as well?


2005-09-11  Eric Botcazou  <ebotcazou@adacore.com>

	* tree.c (contains_placeholder_p) <tcc_expression>: Properly
	handle CALL_EXPR again.


-- 
Eric Botcazou

Index: tree.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree.c,v
retrieving revision 1.502
diff -u -p -r1.502 tree.c
--- ../tree.c	7 Sep 2005 12:39:03 -0000	1.502
+++ ../tree.c	11 Sep 2005 09:56:21 -0000
@@ -2058,6 +2058,9 @@ contains_placeholder_p (tree exp)
 		  || CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1))
 		  || CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 2)));
 
+	case CALL_EXPR:
+	  return CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1));
+
 	default:
 	  break;
 	}