Mark Roulo (nothanks.delete@this.xxx.com) on July 17, 2015 8:19 am wrote:
> Michael S (already5chosen.delete@this.yahoo.com) on July 17, 2015 4:51 am wrote:
> > Jouni Osmala (josmala.delete@this.cc.hut.fi) on July 17, 2015 1:18 am wrote:
> > >
> > >
> > > I believe haswell made the best possible addition to speed up bounds checking. Increasing
> > > the branch unit from one to two. Having already compare and branch as fused operation
> > > means that at execution stage it doesn't take more than one additional operation.
> > >
> >
> > Generally, on that regard, unlike many others I am from
> > you school, i.e. the argument that hardware to speed
> > up bound checks should better be spent to speed up not only bound checks looks to me as very valid.
> >
> > BUT
> >
> > Without deep thinking I can see at least two good reasons
> > for specialized hardware/ISA support for bound checking.
>
> We are getting bounds checkin H/W with Skylake.
>
>     https://en.wikipedia.org/wiki/Intel_MPX
>
> I have no idea about the performance (one hopes it is faster than
> software solutions ...)

MPX sets impossible goal - to help bound checking C. With impossible goal you can't expect too useful results.
With less ambitious goal, like helping bound checks on less wild, but still compilation/JIT-oriented languges one can expect better success.