[cfe-dev] OpenCL/CUDA Interop with PTX Back-End

Peter Collingbourne peter at pcc.me.uk
Tue Oct 4 12:53:08 PDT 2011


On Tue, Oct 04, 2011 at 07:28:26PM +0100, Peter Collingbourne wrote:
> > and the OpenCL frontend seems to respect the address
> >    mapping but does not emit complete array definitions for locally-defined
> >    __local arrays.  Does the front-end currently not support __local arrays
> >    embedded in the code?  It seems to work if the __local arrays are passed as
> >    pointers to the kernel.
> 
> Clang should support __local arrays, and this looks like a genuine
> bug in the IR generator.  I will investigate.

This actually seems to be an optimisation.  Since only the first
element of the array is accessed, LLVM will only allocate storage for
that element.  If you compile your example with -O0 (OpenCL compiles
with optimisations turned on by default), you will see that the 64
element array is created.

Thanks,
-- 
Peter



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