re PR rtl-optimization/15289 (reload error with non-lowpart subregs)

re PR rtl-optimization/15289 (reload error with non-lowpart subregs)

        PR rtl-opt/15289
        * emit-rtl.c (gen_complex_constant_part): Remove.
        (gen_realpart, gen_imagpart): Remove.
        * rtl.h (gen_realpart, gen_imagpart): Remove.
        * expmed.c (extract_bit_field): Remove CONCAT hack catering to
        gen_realpart/gen_imagpart.
        * expr.c (write_complex_part, read_complex_part): New.
        (emit_move_via_alt_mode, emit_move_via_integer, emit_move_resolve_push,
        emit_move_complex_push, emit_move_complex, emit_move_ccmode,
        emit_move_multi_word): Split out from ...
        (emit_move_insn_1): ... here.
        (expand_expr_real_1) <COMPLEX_EXPR>: Use write_complex_part.
        <REALPART_EXPR, IMAGPART_EXPR>: Use read_complex_part.
        * function.c (assign_parm_setup_reg): Hard-code transformations
        instead of using gen_realpart/gen_imagpart.

From-SVN: r91571