re PR target/13958 (Conversion from unsigned to double is painfully slow on P4)

re PR target/13958 (Conversion from unsigned to double is painfully slow on P4)

        PR target/13958
        * config/i386/i386.md ("*floatunssi<mode2>_1"): New pattern with
        corresponding post-reload splitters.
        ("floatunssi<mode>2"): Expand to unsigned_float x87 insn pattern
        when x87 FP math is selected.
        * config/i386/i386-protos.h (ix86_expand_convert_uns_sixf_sse):
        New function prototype.
        * config/i386/i386.c (ix86_expand_convert_uns_sixf_sse): New
        unreachable function to ease macroization of insn patterns.

From-SVN: r133435