"Petar Bajic" <petar.bajic@xxxxxxxxxxxxxxx> writes:
> I need to add conditional move instructions to gcc dlx port.
> I found implemented pattern 'movmodecc' for conditional move
> instruction that look like this:
> if (condition)
> a = b;
> else
> a = c;
>
> but my "movz" look like this
>
> if (c == 0)
> a = b;
>
> or asm: movz r1, r2, r3 ;; ((if r3 == 0, move r2 to r1))
>
> there is no 'else' branch.
>
> In md file it's easy to describe first case:
>
> (define_insn "movsicc_internal"
> [(set (match_operand:SI 0 "register_operand" "=d,d")
> (if_then_else:SI
> (match_operator 1 "comparison_operator" [(match_operand:SI 4
> "register_operand" "=d,d") (const_int 0)])
> (match_operand:SI 2 "register_operand" "=d,d")
> (match_operand:SI 3 "register_operand" "=d,d")))]
>
> "movc\\t%0, %2, %3, %1" ;;theoretic conditional move with else branch
> [(set_attr "mode" "SI")]
>
> But I can't seem to describe what I need: conditional move without
> else branch.
> Any help is appreciated. Im new here.
Write it as a define_expand which generates, more or less,
(set a c)
(set a (if_then_else (eq b 0) d (match_dup a)))
Ian
