re PR tree-optimization/38926 (ice in find_or_generate_expression, at tree-ssa-pre.c:2769)

2009-01-28  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/38926
	* tree-ssa-pre.c (add_to_value): Assert we add only expressions
	with the correct value id to a value.
	(do_regular_insertion): Use the value number of edoubleprime
	for the value number of the expr.

	Revert
	2008-08-21  Richard Guenther  <rguenther@suse.de>
  
        * tree-ssa-pre.c (insert_into_preds_of_block): Before inserting
        a PHI ask VN if it is already available.
        * tree-ssa-sccvn.h (vn_phi_lookup): Declare.
        * tree-ssa-sccvn.c (vn_phi_lookup): Export.

	* gcc.c-torture/compile/pr38926.c: New testcase.

From-SVN: r143725

gcc/ChangeLog

+2009-01-28  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/38926
+	* tree-ssa-pre.c (add_to_value): Assert we add only expressions
+	with the correct value id to a value.
+	(do_regular_insertion): Use the value number of edoubleprime
+	for the value number of the expr.
+
+	Revert
+	2008-08-21  Richard Guenther  <rguenther@suse.de>
+  
+        * tree-ssa-pre.c (insert_into_preds_of_block): Before inserting
+        a PHI ask VN if it is already available.
+        * tree-ssa-sccvn.h (vn_phi_lookup): Declare.
+        * tree-ssa-sccvn.c (vn_phi_lookup): Export.
+
 2009-01-28  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/38934

gcc/testsuite/ChangeLog

+2009-01-28  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/38926
+	* gcc.c-torture/compile/pr38926.c: New testcase.
+
 2009-01-28  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/38934

gcc/testsuite/gcc.c-torture/compile/pr38926.c

+static inline int foo (unsigned _si1)
+{
+  if (_si1 != 0)
+    if (_si1 > 2147483647)
+      return 1;
+  return 0;
+}
+
+static inline unsigned bar (unsigned _left, int _right)
+{
+  return (unsigned) _right >= 8 ? 1 : _left >> _right;
+}
+
+unsigned g_2;
+unsigned g_67;
+volatile unsigned g_162;
+
+static inline int func_62 (unsigned p_63)
+{
+  p_63 = g_2 & g_67;
+  if (g_2)
+    ;
+  else if (p_63)
+    return 1;
+  g_67 = bar (p_63, g_2);
+  return 0;
+}
+
+unsigned baz (void)
+{
+  if (g_2)
+    for (; g_2 <= -16; g_2 = foo (g_2))
+      {
+        for (; g_162; g_162)
+          func_62 (func_62 (0));
+        if (g_67)
+          break;
+      }
+  return g_2;
+}
+

gcc/tree-ssa-pre.c

@@ -434,6 +434,7 @@ static tree create_expression_by_pieces (basic_block, pre_expr, gimple_seq *,
 					 gimple, tree);
 static tree find_or_generate_expression (basic_block, pre_expr, gimple_seq *,
 					 gimple);
+static unsigned int get_expr_value_id (pre_expr);
 
 /* We can add and remove elements and entries to and from sets
    and hash tables, so we use alloc pools for them.  */
@@ -559,6 +560,8 @@ add_to_value (unsigned int v, pre_expr e)
 {
   bitmap_set_t set;
 
+  gcc_assert (get_expr_value_id (e) == v);
+
   if (v >= VEC_length (bitmap_set_t, value_expressions))
     {
       VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
@@ -2975,7 +2978,7 @@ insert_into_preds_of_block (basic_block block, unsigned int exprnum,
   pre_expr eprime;
   edge_iterator ei;
   tree type = get_expr_type (expr);
-  tree temp, res;
+  tree temp;
   gimple phi;
 
   if (dump_file && (dump_flags & TDF_DETAILS))
@@ -3131,8 +3134,12 @@ insert_into_preds_of_block (basic_block block, unsigned int exprnum,
   if (TREE_CODE (type) == COMPLEX_TYPE
       || TREE_CODE (type) == VECTOR_TYPE)
     DECL_GIMPLE_REG_P (temp) = 1;
-
   phi = create_phi_node (temp, block);
+
+  gimple_set_plf (phi, NECESSARY, false);
+  VN_INFO_GET (gimple_phi_result (phi))->valnum = gimple_phi_result (phi);
+  VN_INFO (gimple_phi_result (phi))->value_id = val;
+  VEC_safe_push (gimple, heap, inserted_exprs, phi);
   FOR_EACH_EDGE (pred, ei, block->preds)
     {
       pre_expr ae = avail[pred->src->index];
@@ -3143,20 +3150,6 @@ insert_into_preds_of_block (basic_block block, unsigned int exprnum,
       else
 	add_phi_arg (phi, PRE_EXPR_NAME (avail[pred->src->index]), pred);
     }
-  /* If the PHI node is already available, use it.  */
-  if ((res = vn_phi_lookup (phi)) != NULL_TREE)
-    {
-      gimple_stmt_iterator gsi = gsi_for_stmt (phi);
-      remove_phi_node (&gsi, true);
-      release_defs (phi);
-      add_to_value (val, get_or_alloc_expr_for_name (res));
-      return false;
-    }
-
-  gimple_set_plf (phi, NECESSARY, false);
-  VN_INFO_GET (gimple_phi_result (phi))->valnum = gimple_phi_result (phi);
-  VN_INFO (gimple_phi_result (phi))->value_id = val;
-  VEC_safe_push (gimple, heap, inserted_exprs, phi);
 
   newphi = get_or_alloc_expr_for_name (gimple_phi_result (phi));
   add_to_value (val, newphi);
@@ -3330,7 +3323,7 @@ do_regular_insertion (basic_block block, basic_block dom)
 			  pre_stats.constified++;
 			}
 		      else
-			info->valnum = PRE_EXPR_NAME (edoubleprime);
+			info->valnum = VN_INFO (PRE_EXPR_NAME (edoubleprime))->valnum;
 		      info->value_id = new_val;
 		    }
 		}

gcc/tree-ssa-sccvn.c

@@ -1481,7 +1481,7 @@ static VEC(tree, heap) *shared_lookup_phiargs;
    value number if it exists in the hash table.  Return NULL_TREE if
    it does not exist in the hash table. */
 
-tree
+static tree
 vn_phi_lookup (gimple phi)
 {
   void **slot;

gcc/tree-ssa-sccvn.h

@@ -184,7 +184,6 @@ vn_reference_t vn_reference_insert (tree, tree, VEC (tree, gc) *);
 vn_reference_t vn_reference_insert_pieces (VEC (tree, gc) *,
 					   VEC (vn_reference_op_s, heap) *,
 					   tree, unsigned int);
-tree vn_phi_lookup (gimple);
 
 hashval_t vn_nary_op_compute_hash (const vn_nary_op_t);
 int vn_nary_op_eq (const void *, const void *);