On Fri, Nov 13, 2015 at 04:56:30PM +0100, Jakub Jelinek wrote:
> On Fri, Nov 13, 2015 at 04:53:05PM +0100, Marek Polacek wrote:
> > On Fri, Nov 13, 2015 at 04:44:21PM +0100, Bernd Schmidt wrote:
> > > I don't think so, the three codes are adjacent so we should be generating
> > > "(unsigned)(code - RECORD_TYPE) < 3".
> >
> > Interesting. Yeah, if we change the RECORD_OR_UNION_TYPE_P macro to this
> > form, then we don't need a separate version for the C FE.
>
> Why? The compiler should do that already, or do you care about
> -O0 builds or host compilers other than gcc that aren't able to do this?
I don't.
> The disadvantage of writing it manually that way is that you need to assert
> somewhere that the 3 values indeed are consecutive, while
> when the (host?) compiler performs this optimization, it does that only if
> they are consecutive, if they are not, the code will be just less efficient.
Ok, I understand now what Bernd meant. I didn't realize the compiler already
does such optimization with those _TYPEs...
Marek
