[cfe-dev] Casting scalars to vectors
clattner at apple.com
Mon Apr 19 18:04:51 PDT 2010
On Apr 19, 2010, at 6:02 PM, John Thompson wrote:
> >I'm pretty sure that's already implemented... are you passing
> >-faltivec to clang?
> This stops the error, but is it enough?:
That should be enough, if you like that patch go ahead and commit it (with a testcase).
> Index: lib/Sema/SemaInit.cpp
> --- lib/Sema/SemaInit.cpp (revision 101528)
> +++ lib/Sema/SemaInit.cpp (working copy)
> @@ -886,7 +886,7 @@
> // OpenCL & AltiVec require all elements to be initialized.
> if (numEltsInit != maxElements)
> - if (SemaRef.getLangOptions().OpenCL || SemaRef.getLangOptions().AltiVec)
> + if (SemaRef.getLangOptions().OpenCL)
> << (numEltsInit < maxElements) << maxElements << numEltsInit;
> On Mon, Apr 19, 2010 at 4:07 PM, Eli Friedman <eli.friedman at gmail.com> wrote:
> On Mon, Apr 19, 2010 at 3:00 PM, John Thompson
> <john.thompson.jtsoftware at gmail.com> wrote:
> > My colleague pointed out that it's not a cast, but a literal, which Clang
> > should support.
> I'm pretty sure that's already implemented... are you passing
> -faltivec to clang?
> > -John
> > On Mon, Apr 19, 2010 at 11:45 AM, John Thompson
> > <john.thompson.jtsoftware at gmail.com> wrote:
> >> According to the AltiVec standard (section 2.4.6 in
> >> http://www.freescale.com/files/32bit/doc/ref_manual/ALTIVECPIM.pdf), casting
> >> a scalar to a vector is illegal, yet gcc seems to support it, as seen in
> >> many of those little files in the PS3 SDK in target\ppu\include\bits, which
> >> have statements like:
> >> vec_uint4 mask = (vec_uint4)(vec_int4)(-1);
> >> where vec_uint4 and vec_int4 are typedefs for vector types, i.e.:
> >> typedef vector int vec_int4;
> >> What does this actually do? I'm guessing it's supposed to fill the vector
> >> components with -1.
> >> How should this be handled in Clang?
> >> I filed a Bugzilla bug 6846 on this.
> >> If Clang should support it
> >> , I might be able to take a crack at it, with a little guidance.
> >> --
> >> John Thompson
> >> John.Thompson.JTSoftware at gmail.com
> > --
> > John Thompson
> > John.Thompson.JTSoftware at gmail.com
> > _______________________________________________
> > cfe-dev mailing list
> > cfe-dev at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
> John Thompson
> John.Thompson.JTSoftware at gmail.com
> cfe-dev mailing list
> cfe-dev at cs.uiuc.edu
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