[Beignet] [PATCH] LibOcl: Fix float convert to long/ulong bug.

[Yang, Rong R]

> -----Original Message-----
> From: Song, Ruiling
> Sent: Wednesday, October 21, 2015 14:17
> To: Yang, Rong R; beignet at lists.freedesktop.org
> Subject: RE: [Beignet] [PATCH] LibOcl: Fix float convert to long/ulong bug.
> 
> > > > +OVERLOADABLE DSTTYPE convert_ ## DSTTYPE ## _sat(SRCTYPE x) { \
> > > > +  return x >= SRC_MAX ? DST_MAX : x <= SRC_MIN ?
> (DSTTYPE)DST_MIN :
> > > > (DSTTYPE)x; \
> > >
> > > Why don't you use two sentences here？suppose this kind of writing
> > > would generate if-else blocks?
> > > Other parts LGTM.
> > It is hard to use two sentences. Think about two methods:
> >
> > x = x >= SRC_MAX ? DST_MAX : x;
> > return x <= SRC_ MIN? (DSTTYPE) DST_MIN: (DSTTYPE)x; The second
> > sentences may convert SRC_MAX to DSTTYPE  and return, because
> SRC_MAX
> > is overflow, so the value may be undefined.
> >
> > Another methods:
> > DSTTYPE y = x >= SRC_MAX ? DST_MAX: (DSTTYPE)x; return x <= SRC_MIN ?
> > (DSTTYPE) DST_MIN : (DSTTYPE)y; But in the first sentences, when
> > convert x to y, the x may underflow, so the y also may be undefined.
> Underflow would only occur if x<= SRC_MIN, right?
> Then the final result would be DST_MIN. so the final result is also defined.
> What I mean is this kind of form. This form would avoid unnecessary if-else
> extra basic block generation I think.
Yes, The second mothed looks ok, of course, its performance is better than previous, I will send a new version.

> >
> > Don't you have other suggestion?