RE: move patterns, emit_move_insn

["venkat" <venkat at acmet dot com>]

Please see my reply below.

> -----Original Message-----
> From: Florent DEFAY [mailto:spira.inhabitant@gmail.com]
> Sent: Tuesday, March 03, 2009 3:10 PM
> To: gcc-help@gcc.gnu.org
> Subject: Re: move patterns, emit_move_insn
> 
> Thank you for your help.
> 
> Regarding your advice, I tried this implementation:
> 
> ___________________________________________________
> ;; movhi
> (define_expand "movhi"
>   [(set (match_operand:HI 0 "nonimmediate_operand" "")
>         (match_operand:HI 1 "general_operand" "")
>   )]
>   ""
>   ""
> )
> 
> (define_insn "movhi1"
>   [(set (match_operand:HI 0 "register_operand" "=r,r,m,r")
>         (match_operand:HI 1 "general_operand" "r,m,r,i")
>   )]
>   ""
>   "@
>   movew\t%1,%0
>   movew\t%1,%0
>   movew\t%1,%0
>   movew\t%1,%0"
> )
> ____________________________________________________
> 
> But I get this error then:
> 
> e.c:7: error: unrecognizable insn:
> (insn 7 6 8 3 e.c:4 (set (mem/c/i:HI (reg/f:HI 14) [0 i+0 S2 A16])
>         (const_int 3 [0x3])) -1 (nil))
> 
> I think GCC has to put immediate into memory. The arch can't do that
> directly. GCC should put the immediate in register and then register
> to memory.
> It succeded with old implementation (with a lot of define_insn). What
> should I change in the new implementation to get it right ?

In your 'define_expand' try forcing the source operand in to a register.
Then try to move it to destination.

Please see whether 'mips_legitimize_move' function in 'mips.c' is useful.  

> 
> Another question, I wonder how to deal with access modes ?
> For example, to obtain such an ASM instruction
> movew r1,8(r2)
> should it come from a define_insn like movhi1 and then treated by
> print_operand ?
> 
> Thank you.
> Regards.
> 
> Florent