tree-ssa-forwprop.c (forward_propagate_into_cond): For combining both operands requir...

2007-10-12  Richard Guenther <rguenther@suse.de>

	* tree-ssa-forwprop.c (forward_propagate_into_cond): For
	combining both operands require either both have single uses
	or combining to a constant.

From-SVN: r129261

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 600d82df58fffbda9d5dd3fe6a1d99312d3e699e..9e7a02b30cc5700b254dd829c622f609c0832b16 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2007-10-12  Richard Guenther <rguenther@suse.de>
+
+       * tree-ssa-forwprop.c (forward_propagate_into_cond): For
+       combining both operands require either both have single uses
+       or combining to a constant.
+
 2007-10-12  Richard Guenther  <rguenther@suse.de>
 
        PR middle-end/26198

diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c
index b92a9f13f48662f23edce7ef8adda93d3339ab0f..047d057bfc997a5377c9a1ae105e4c815b2464c4 100644 (file)
--- a/gcc/tree-ssa-forwprop.c
+++ b/gcc/tree-ssa-forwprop.c
@@ -360,7 +360,7 @@ forward_propagate_into_cond (tree cond_expr, tree stmt)
     tree tmp = NULL_TREE;
     tree cond = COND_EXPR_COND (cond_expr);
     tree name, def_stmt, rhs0 = NULL_TREE, rhs1 = NULL_TREE;
-    bool single_use_p;
+    bool single_use0_p = false, single_use1_p = false;
 
     /* We can do tree combining on SSA_NAME and comparison expressions.  */
     if (COMPARISON_CLASS_P (cond)
@@ -369,7 +369,7 @@ forward_propagate_into_cond (tree cond_expr, tree stmt)
        /* For comparisons use the first operand, that is likely to
           simplify comparisons against constants.  */
        name = TREE_OPERAND (cond, 0);
-       def_stmt = get_prop_source_stmt (name, false, &single_use_p);
+       def_stmt = get_prop_source_stmt (name, false, &single_use0_p);
        if (def_stmt != NULL_TREE
            && can_propagate_from (def_stmt))
          {
@@ -377,7 +377,7 @@ forward_propagate_into_cond (tree cond_expr, tree stmt)
            rhs0 = GIMPLE_STMT_OPERAND (def_stmt, 1);
            tmp = combine_cond_expr_cond (TREE_CODE (cond), boolean_type_node,
                                          fold_convert (TREE_TYPE (op1), rhs0),
-                                         op1, !single_use_p);
+                                         op1, !single_use0_p);
          }
        /* If that wasn't successful, try the second operand.  */
        if (tmp == NULL_TREE
@@ -385,7 +385,7 @@ forward_propagate_into_cond (tree cond_expr, tree stmt)
          {
            tree op0 = TREE_OPERAND (cond, 0);
            name = TREE_OPERAND (cond, 1);
-           def_stmt = get_prop_source_stmt (name, false, &single_use_p);
+           def_stmt = get_prop_source_stmt (name, false, &single_use1_p);
            if (def_stmt == NULL_TREE
                || !can_propagate_from (def_stmt))
              return did_something;
@@ -394,7 +394,7 @@ forward_propagate_into_cond (tree cond_expr, tree stmt)
            tmp = combine_cond_expr_cond (TREE_CODE (cond), boolean_type_node,
                                          op0,
                                          fold_convert (TREE_TYPE (op0), rhs1),
-                                         !single_use_p);
+                                         !single_use1_p);
          }
        /* If that wasn't successful either, try both operands.  */
        if (tmp == NULL_TREE
@@ -403,7 +403,7 @@ forward_propagate_into_cond (tree cond_expr, tree stmt)
          tmp = combine_cond_expr_cond (TREE_CODE (cond), boolean_type_node,
                                        rhs0,
                                        fold_convert (TREE_TYPE (rhs0), rhs1),
-                                       !single_use_p);
+                                       !(single_use0_p && single_use1_p));
       }
     else if (TREE_CODE (cond) == SSA_NAME)
       {