[prev in list] [next in list] [prev in thread] [next in thread] 

List:       cfe-dev
Subject:    Re: [cfe-dev] Question about OpenCL language standard option
From:       jingu <jingu () codeplay ! com>
Date:       2013-11-30 8:49:03
Message-ID: 5299A67F.2000905 () codeplay ! com
[Download RAW message or body]

Hi Arthur, Joey,

I  appreciate your response. As Arthur mentioned, I assumed this is not 
VLA because there is 'const' qualifier and this example is included in 
one OpenCL test-suite and clang folded this with 'GNUMode' not VLA. I am 
sorry it was my mistake. Thank you for your response, again.

Sincerely,
JinGu Kang

2013-11-30 ́˜¤́ „ 10:59, Arthur O'Dwyer ́“´ 글:
> Joey, JinGu,
> 
> I believe JinGu was expecting the array to be not-a-VLA, because its
> size is "const". In C++ JinGu would be correct; that array's size *is*
> a compile-time constant in C++, but in C (and therefore in OpenCL)
> it's not constant, because it depends on the value of a variable. (The
> variable's type happens to be const-qualified, but that doesn't matter
> in C.)
> 
> If this test case came from an official OpenCL test suite, IMHO the
> right course of action is almost certainly to contact the maker of
> that test suite and get them to change their test, rather than add an
> extension to Clang just for this one special case.  (Alternatively, is
> there such a thing as OpenCL++? Should this test be compiled in that
> mode?)
> 
> HTH,
> –Arthur
> 
> 
> On Fri, Nov 29, 2013 at 5:32 PM, Joey Gouly <Joey.Gouly@arm.com> wrote:
> > 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@cs.uiuc.edu [cfe-commits-bounces@cs.uiuc.edu] On Behalf \
> >                 Of JinGu Kang [jingu@codeplay.com]
> > Sent: 29 November 2013 17:32
> > To: cfe-dev@cs.uiuc.edu; cfe-commits@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
> > 
> > -- IMPORTANT NOTICE: The contents of this email and any attachments are \
> > confidential and may also be privileged. If you are not the intended recipient, \
> > please notify the sender immediately and do not disclose the contents to any \
> > other person, use it for any purpose, or store or copy the information in any \
> > medium.  Thank you. 
> > ARM Limited, Registered office 110 Fulbourn Road, Cambridge CB1 9NJ, Registered \
> > in England & Wales, Company No:  2557590 ARM Holdings plc, Registered office 110 \
> > Fulbourn Road, Cambridge CB1 9NJ, Registered in England & Wales, Company No:  \
> > 2548782 
> > 
> > _______________________________________________
> > cfe-commits mailing list
> > cfe-commits@cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits

_______________________________________________
cfe-dev mailing list
cfe-dev@cs.uiuc.edu
http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev


[prev in list] [next in list] [prev in thread] [next in thread]