tree.c (tree_expr_nonnegative_p): New function.

        * tree.c (tree_expr_nonnegative_p): New function.

        * tree.h (tree_expr_nonnegative_p): Declare.

        * c-typeck.c (build_binary_op): Call `tree_expr_nonnegative_p' to
        elide some sign_compare warnings.
        (build_conditional_expr): Likewise.

cp:
        * typeck.c (build_binary_op): Call `tree_expr_nonnegative_p' to elide
        some sign_compare warnings.

From-SVN: r33019

1 files changed, 19 insertions, 0 deletions

diff --git a/gcc/tree.c b/gcc/tree.c
index 53ca207..66078e5 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -4370,6 +4370,25 @@ tree_int_cst_sgn (t)
     return 1;
 }
 
+/* Return true if `t' is known to be non-negative.  */
+
+int
+tree_expr_nonnegative_p (t)
+     tree t;
+{
+  switch (TREE_CODE (t))
+    {
+    case INTEGER_CST:
+      return tree_int_cst_sgn (t) >= 0;
+    case COND_EXPR:
+      return tree_expr_nonnegative_p (TREE_OPERAND (t, 1))
+	&& tree_expr_nonnegative_p (TREE_OPERAND (t, 2));
+    default:
+      /* We don't know sign of `t', so be safe and return false.  */
+      return 0;
+    }
+}
+
 /* Compare two constructor-element-type constants.  Return 1 if the lists
    are known to be equal; otherwise return 0.  */