move patterns, emit_move_insn

[Florent DEFAY <spira.inhabitant@xxxxxxxxx>]

Hi,

I am porting GCC on a new arch. I have just been trying to do the
"prologue" pattern.

I do it this way :
______________________________________________
(define_expand "prologue"
  [(clobber (const_int 0))]
  ""
  {
    function_prologue();
    DONE;
  }
)
______________________________________________

where function_prologue is defined (and not finished) in target.c like this :
______________________________________________
function_prologue()
{
        emit_move_insn (gen_rtx_REG (HImode, FRAME_POINTER_REGNUM),
                                 gen_rtx_REG (HImode, STACK_POINTER_REGNUM));

}
_____________________________________________

And move in HImode is defined by these patterns in the md :
_____________________________________________

;; move word   expand
(define_expand "movhi"
  [(set (match_operand:HI 0 "nonimmediate_operand" "=r, m")
        (match_operand:HI 1 "general_operand" "rmi,r")
  )]
  ""
  ""
)

;; move word   r -> r
(define_insn "movhi_r_r"
  [(set (match_operand:HI 0 "register_operand" "=r")
        (match_operand:HI 1 "register_operand" "r")
  )]
  ""
  "movew\t%1,%0"
)

;; move word   i -> r
(define_insn "movhi_i_r"
  [(set (match_operand:HI 0 "register_operand" "=r")
        (match_operand:HI 1 "immediate_operand" "i")
  )]
  ""
  "movew\t%1,%0"
)

;; move word   (r) -> r
(define_insn "movhi_m1_r"
  [(set (match_operand:HI 0 "general_operand" "=r")
        (mem:HI (match_operand:HI 1 "register_operand" "r"))
  )]
  ""
  "movew\t(%1),%0"
)

;; move word   r -> (r)
(define_insn "movhi_r_m1"
  [(set (mem:HI (match_operand:HI 0 "register_operand" "r"))
        (match_operand:HI 1 "general_operand" "r")
  )]
  ""
  "movew\t%1,(%0)"
)
_______________________________________

I suppose my patterns for move are not well implemented.
When I run GCC I have this error :

[guest1]$ target-gcc e.c  -S
e.c: In function ‘nothing’:
e.c:7: error: insn does not satisfy its constraints:
(insn 21 3 22 e.c:3 (set (reg/f:HI 5 r5)
        (reg/f:HI 6 r6)) 7 {movhi_r_r} (nil))

e.c
__________________________
void nothing (void)
{
        int i = 3;

        i = 4 + 2;
}
__________________________

The error appeared since I added the "emit_move_insn" in the
function_prologue. Before that, GCC compiled e.c well.
I tried to redo patterns and especially constraints and predicates. I
did not success to avoid the error.

GCC already succeeded in compiling a register to register move with
source code like
int i = 3;
(I mean the pattern movhi_r_r has served successfully).

I would like to know if the error is due to patterns and what is the
link with emit_move_insn ?
Looking for any explaination or advice.

Thank you for your help.
Regards.

Florent