Segment registers support for i386

[Rask Ingemann Lambertsen]

On Mon, May 15, 2006 at 12:09:00AM +0800, Rémy Saissy wrote:
 
> To manage the manipulation of the register class, I added entries in
> the i386.md file.
> 
> ;; get a value from a segment register.
> (define_insn "store_seg"
>  [(set (match_operand:SI 0 "nonimmediate_operand" "")
>        (match_operand:SI 1 "general_operand" "s"))]
>        ""
>        "movl\t%1,%0")
> 
> ;; set a value in a segment register.
> (define_insn "load_seg"
>  [(set (match_operand:SI 0 "general_operand" "=s")
>        (match_operand:SI 1 "register_operand" ""))]
>        ""
>        "movl\t%1,%0")

I think you'll have to add "s" alternatives to the *movhi pattern instead of
adding two new patterns, since otherwise there will be two nearly identical
patterns and GCC might use the wrong one. If you need patterns named
"store_seg" and "load_seg", use an expander.

-- 
Rask Ingemann Lambertsen