Re: move patterns, emit_move_insn

[Georg-Johann Lay <avr at gjlay dot de>]

Florent DEFAY schrieb:
> Thank you very much for your attention.
>
> Meena, could you please give me advice about how to set up eliminating
> FP against SP ? In my target.h, these macros are NOT defined :
> ELIMINABLE_REGS
> CAN_ELIMINATE
> INITIAL_ELIMINATION_OFFSET
>
> I changed target.md :
> ________________________________________
> ;; movhi
> (define_expand "movhi"
>   [(set (match_operand:HI 0 "nonimmediate_operand" "")
>         (match_operand:HI 1 "general_operand" "")
>   )]
>   ""
>   {
>     /* First try */
>     /*
>     if (GET_CODE (operands[0]) == MEM
>      && GET_CODE (operands[1]) != REG)
>     {
>       operands[1] = force_reg (HImode, operands[1]);
>     }
>     */
>     /* Second try */
>     if (!register_operand(operand0, HImode)
>     && !register_operand(operand1, HImode))
>     {
>       operands[1] = copy_to_mode_reg(HImode, operand1);
>     }
>   }
> )
>
> ;; move.w   r -> (r)
> (define_insn "movhi1"
>   [(set (match_operand:HI 0 "nonimmediate_operand" "=r,m,r,r")
>         (match_operand:HI 1 "general_operand" "r,r,m,i")
>   )]
>   ""
>   "@
>   move.w\t%1,%0
>   move.w\t%1,%0
>   move.w\t%1,%0
>   move.w\t%1,%0"
> )
> ______________________________
>
> First and second try (as commented in the code) are successful to
Don't use "first try". There are other rtx that want to be moved like 
SUBREG.
> force copying immediate into register and then register into memory.
> But then, with both of them, this error appears:
>
> e.c:7: error: unrecognizable insn:
> (insn 8 7 9 3 e.c:4 (set (mem/c/i:HI (reg/f:HI 14) [0 i+0 S2 A16])
>         (reg:HI 15)) -1 (nil))
>
> I don't know why. Since the pattern movhi1 allows register to memory transfer.

Obviously, it does *not*. Reason could be memory_operand and the 
addresses that you allow/don't allow in struct rtl. So check the 
addressing stuff, e.g. LEGITIMIZE_ADDRESS, GO_IF_LEGITIMATE_ADDRESS et al.

Georg-Johann