Re: RFC: objc_msgSend efficiency patch

[Dale Johannesen <dalej at apple dot com>]

On Feb 21, 2005, at 10:59 PM, Kai Henningsen wrote:

> dalej@apple.com (Dale Johannesen)  wrote on 21.02.05 in 
> <206777C6-846E-11D9-8055-000393D76DAA@apple.com>:
>
> > Simple Objective C programs such as
> >
> > #include <objc/Object.h>
> > void foo(void) {
> >    Object *o;
> >    [o++ free];
> > }
> >
> > result in calling objc_msgSend indirectly through a pointer, instead
> > of directly as they did in 3.3.  This seems to happen only at low
> > optimization
> > levels; still, it's a performance regression.  The reason is that the
> > gimplifier
> > puts the result of the OBJ_TYPE_REF into a temp due to the
> > postincrement.
>
> I thought current tree optimizers should be able to figure this out?

They do, as I said, this happens only at low optimization levels.