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.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@143725 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 10 insertions, 17 deletions

diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c
index 0717a366bf3..a3f91f07d58 100644
--- a/gcc/tree-ssa-pre.c
+++ b/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;
 		    }
 		}