On 02 Mar 15:22, Kyrill Tkachov wrote:
> Hi all,
>
> I'm looking at using the define_subst machinery to auto-generate
> zero-extended
> versions of some patterns, for example having:
> (set reg:SI
> (xor:SI a:SI b:SI))
>
> generate a pattern of the form:
> (set reg:DI
> (zero_extend:DI
> (xor:SI (a:SI b:SI))))
>
> How do I go about achieving this? From the documentation, I think I need
> something like:
> (define_subst "add_z_extend"
> [(set (match_operand:SI 0 "" "")
> (match_operand:SI 1 "" ""))]
> ""
> [(set (match_dup 0)
> (zero_extend:DI (match_dup 1)))]
>
> but in the resultant pattern I need operand 0 to be tranfsormed into DImode.
> Is there a way to write that?
>
Can't you just use [(set (match_operand:DI 0 "" "")... instead of
match_dup?
