Re: inline assembly vs. intrinsic functions

[roy rosen <roy dot 1rosen at gmail dot com>]

2011/3/24 Ian Lance Taylor <iant@google.com>:
> roy rosen <roy.1rosen@gmail.com> writes:
>
>>> You build a RECORD_TYPE holding the fields you want to return. ?You
>>> define the appropriate builtin functions to return that record type.
>>
>> How is that done? using define_insn? How do I tell it to return a struct?
>> Is there an example I can look at?
>
> A RECORD_TYPE is what gcc generates when you define a struct in your
> source code. ?For an example of a backend building a struct, see, e.g.,
> ix86_build_builtin_va_list_abi.
>
> When you define your builtin functions in TARGET_INIT_BUILTINS you
> specify the argument types and the return type, typically by building a
> FUNCTION_TYPE and passing it to add_builtin_function. ?To define a
> builtin which returns a struct, just arrange for the return type of the
> FUNCTION_TYPE that you pass to add_builtin_function be the RECORD_TYPE
> that you built.

I understood this part.
What I don't understand is:
In addition to adding the builtin function, in the md file I have a
define_insn for each built in, for example:

(define_insn "A_ssodssxx2w"
	[(set (match_operand:SI 0 "register_operand" "=d ")
	(unspec:SI [(match_operand:SI 1 "register_operand" "d ")
	(match_operand:SI 2 "register_operand" "d ")]
	UNSPEC_A_SSODSSXX2W))]
	""
	"ssodssxx.2w %2,%1,%0 %!"
)

How do I create something equivalent which would have an rtl set
expression to the structure.

Thanks, Roy.

>
> Ian
>