fold-const.c (tree_expr_nonnegative_p): Only return true for ABS_EXPR when flag_wrapv is false because of INT_MIN.

2005-07-19  James A. Morrison  <phython@gcc.gnu.org>

        * fold-const.c (tree_expr_nonnegative_p): Only return true for
        ABS_EXPR when flag_wrapv is false because of INT_MIN.
        (tree_expr_nonzero_p): Always call tree_expr_nonzero_p on the argument
        of an ABS_EXPR.
        (fold_unary): Always fold ABS_EXPR<ABS_EXPR<x>> into
        ABS_EXPR<x>.

From-SVN: r102184