[cfe-dev] Question about OpenCL language standard option

[Joey Gouly]

Hi JinGu,

I'm not sure I understand.. VLAs are *not* supported in OpenCL. See Restrictions 6.9.d.

Thanks,
Joey
________________________________________
From: cfe-commits-bounces at cs.uiuc.edu [cfe-commits-bounces at cs.uiuc.edu] On Behalf Of JinGu Kang [jingu at codeplay.com]
Sent: 29 November 2013 17:32
To: cfe-dev at cs.uiuc.edu; cfe-commits at cs.uiuc.edu
Subject: Question about OpenCL language standard option

Hi all,

I got a error from a opencl test. The test code is as following:

source code:
__kernel void test_fn(__global uint *src, __global uint4 *results) {
   const size_t SIZE = 128;
   int tid = get_global_id(0);
   if (tid*4 >= SIZE)
     return;
   __private uint sPrivateStorage[SIZE];
   for (size_t i=0 ; i<SIZE ; i++)
     sPrivateStorage[i] = src[i];
   results[tid] = vload4(tid, sPrivateStorage);
}

and the error message is as following:

"error: variable length arrays are not supported in OpenCL
   __private uint sPrivateStorage[SIZE];"

The problem is that 'isArraySizeVLA' function calls
'VerifyIntegerConstantExpression' with 'S.LangOpts.GNUMode'. The OpenCL
Language standard option does not have this option. It causes a error
because 'AllowFold' is not set to 1. In order to fix this error, I think
that we need to insert 'GNUMode' to  OpenCL LANGSTANDARD or modify
sligtly checking code. How do you feel about this? I can not guarantee
the side effect of 'GNUMode' with OpenCL. I have attached a simple patch
as reference. If there is something wrong, please let me know.

Thanks,
JinGu Kang

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