[cfe-dev] [pocl-devel] [LLVMdev] SPIR provisional specification is now available in the Khronos website

Pekka Jääskeläinen pekka.jaaskelainen at tut.fi
Fri Sep 28 13:16:50 PDT 2012


On 09/28/2012 07:45 PM, James Molloy wrote:
> That would be a simple, reasonable restriction that would stop potentially
> maliciously horrible test cases causing all CPU SPIR clients to write upwards of
> a hundred lines of conversion code.

Are you proposing to disallow the use of an IR instruction type to *possibly*
avoid problems from the (slight) misuse of another LLVM IR construct?

IMHO there should be a more robust solution that solves the misused construct
instead of just trying to "put out the fires it creates". E.g. some sort of
"thread local"-type of qualifier for the global which disallows certain
optimizations. A new linkage type perhaps? Someone more familiar with the
LLVM IR than me might have a better idea.

I understand that adding the automatic local as a kernel argument (in the specs)
is too intrusive now given the existing implementations that do it
otherwise, especially for those for which the semantics "happens" to be
correct as is. That is, the currently popular GPUs with separate
local/scratchpad memories.

Have a nice weekend,
-- 
--Pekka




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