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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Thanks John for your comments. I will try adding builtin functions for OpenCL atomics instead.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Anastasia, Alexey,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">To allow OpenCL implementations have flexibility of their own implementation of OpenCL atomic builtin functions, I think the clang atomic builtin functions for OpenCL should
not have the same name as the OpenCL atomic builtin functions, instead they can have names like __opencl_atomic_*. What do you think?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Thanks.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Sam<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> rjmccall@apple.com [mailto:rjmccall@apple.com]
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<b>Sent:</b> Tuesday, January 17, 2017 2:45 PM<br>
<b>To:</b> Anastasia Stulova <Anastasia.Stulova@arm.com><br>
<b>Cc:</b> Liu, Yaxun (Sam) <Yaxun.Liu@amd.com>; cfe-dev (cfe-dev@lists.llvm.org) <cfe-dev@lists.llvm.org>; nd <nd@arm.com>; Tye, Tony <Tony.Tye@amd.com>; Bader, Alexey (alexey.bader@intel.com) <alexey.bader@intel.com>; Sumner, Brian <Brian.Sumner@amd.com>;
Zhuravlyov, Konstantin <Konstantin.Zhuravlyov@amd.com><br>
<b>Subject:</b> Re: [cfe-dev] [RFC] Support synchronisation scope in Clang atomic builtin functions<o:p></o:p></span></p>
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<p class="MsoNormal">On Jan 17, 2017, at 1:54 PM, Anastasia Stulova via cfe-dev <<a href="mailto:cfe-dev@lists.llvm.org">cfe-dev@lists.llvm.org</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">FYI, reference to the relevant part of the OpenCL spec:<span class="apple-converted-space"> </span><a href="https://www.khronos.org/registry/OpenCL/specs/opencl-2.0-openclc.pdf#105"><span style="color:#954F72">https://www.khronos.org/registry/OpenCL/specs/opencl-2.0-openclc.pdf#105</span></a></span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">From the OpenCL side this proposal seems to make sense generally. I am not quite clear though what would happen with the scopes other than synch_scope_single_thread.</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Do you need to extend the IR language to accommodate that too in addition to ‘singlethread’ flag you already use?</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal">Thank you for linking the actual language specification. It seems clear to me now that we just need to introduce new builtin functions specifically for OpenCL. The OpenCL implementation in IRGen can then just handle different constants
however it wishes.<o:p></o:p></p>
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<p class="MsoNormal">John.<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Cheers,</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Anastasia</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif">From:</span></b><span class="apple-converted-space"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif"> </span></span><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif">Liu,
Yaxun (Sam) [<a href="mailto:Yaxun.Liu@amd.com"><span style="color:#954F72">mailto:Yaxun.Liu@amd.com</span></a>]<span class="apple-converted-space"> </span><br>
<b>Sent:</b><span class="apple-converted-space"> </span>17 January 2017 17:16<br>
<b>To:</b><span class="apple-converted-space"> </span>cfe-dev (<a href="mailto:cfe-dev@lists.llvm.org"><span style="color:#954F72">cfe-dev@lists.llvm.org</span></a>)<br>
<b>Cc:</b><span class="apple-converted-space"> </span>Sumner, Brian; Tye, Tony; Zhuravlyov, Konstantin; Anastasia Stulova; Bader, Alexey (<a href="mailto:alexey.bader@intel.com"><span style="color:#954F72">alexey.bader@intel.com</span></a>)<br>
<b>Subject:</b><span class="apple-converted-space"> </span>[RFC] Support synchronisation scope in Clang atomic builtin functions</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<span style="font-size:10.0pt;font-family:"Segoe UI",sans-serif">OpenCL 2.0 atomic builtin functions have a scope argument which is ideally represented as synchronization scope argument in LLVM atomic instructions.</span><o:p></o:p></p>
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<span style="font-size:10.0pt;font-family:"Segoe UI",sans-serif">Clang supports translating Clang atomic builtin functions to LLVM atomic instructions. However it currently does not support synchronization scope of LLVM atomic instructions. Without this, users
have to use LLVM assembly code to implement OpenCL atomic builtin functions.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;margin-bottom:9.0pt;background:white;font-variant-ligatures: normal;font-variant-caps: normal;orphans: 2;widows: 2;-webkit-text-stroke-width: 0px;background-position:initial initial;background-repeat:initial initial;word-spacing:0px">
<span style="font-size:10.0pt;font-family:"Segoe UI",sans-serif">I have a patch (<a href="https://reviews.llvm.org/D28691"><span style="color:#954F72">https://reviews.llvm.org/D28691</span></a><span class="apple-converted-space"> </span>) which allows Clang
atomic builtin functions to accept an optional synchronization scope argument, so that they can be used to implement OpenCL atomic builtin functions.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;margin-bottom:9.0pt;background:white;font-variant-ligatures: normal;font-variant-caps: normal;orphans: 2;widows: 2;-webkit-text-stroke-width: 0px;background-position:initial initial;background-repeat:initial initial;word-spacing:0px">
<span style="font-size:10.0pt;font-family:"Segoe UI",sans-serif">This patch will not just benefits OpenCL. It will benefit any languages which need to generate atomic instructions with synchronization scopes. For languages not using synchronization scopes there
is no functional change, since the synchronization scope argument is optional, and its default value generates the same LLVM instruction as before.</span><o:p></o:p></p>
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<span style="font-size:10.0pt;font-family:"Segoe UI",sans-serif">Your comments are welcome.</span><o:p></o:p></p>
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<span style="font-size:10.0pt;font-family:"Segoe UI",sans-serif;background:white">Thanks.</span><o:p></o:p></p>
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<span style="font-size:10.0pt;font-family:"Segoe UI",sans-serif;background:white">Sam</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif">_______________________________________________<br>
cfe-dev mailing list<br>
</span><a href="mailto:cfe-dev@lists.llvm.org"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:#954F72">cfe-dev@lists.llvm.org</span></a><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif"><br>
</span><a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:#954F72">http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev</span></a><o:p></o:p></p>
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