🚀 go-pugleaf

dillon@overload.Berkeley.CA.US (Matthew Dillon) writes:
>    Well, actually, while the built-in stuff is cute it is also pretty
>    useless in most cases.  For example, the code for a 'full' version of
>    setmem()/memset(), movmem()/memmov(), etc.... is pretty big, but also
>    can be a hell of a lot faster (using MOVEM's or at least long ops
>    instead of char ops).  I think the only real builtin function that
>    is useful is, maybe, strlen().

__builtin_strlen() is definitely useful. SAS/C evaluates 
strlen("string constant") at compile time.  I don't know how good the
builtin versions of the other functions are, but if the compiler knows
anything about arguments to the function at compile time, it can
use different versions of the move/set code for small/large size,
aligned/unaligned, etc.  If no information is available, it can always
call the general routine.

Also, because the compiler knows about any side-effects of the builtin, it
can optimize the code around the builtin more than if it was just an arbitrary
function call.
--
Ed Hanway --- uunet!sisd!jeh
Some of the trademarks mentioned in this product are for identification
purposes only.  All models are over 18 years of age.