PR tree-optimization/83896 - ice in get_string_len on a call to strlen with
non-constant length

gcc/ChangeLog:

        PR tree-optimization/83896
        * tree-ssa-strlen.c (get_string_len): Rename...
        (get_string_cst_length): ...to this.  Return HOST_WIDE_INT.
        Avoid assuming length is constant.
        (handle_char_store): Use HOST_WIDE_INT for string length.

gcc/testsuite/ChangeLog:

        PR tree-optimization/83896
        * gcc.dg/strlenopt-43.c: New test.

From-SVN: r257100