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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D">This is discussed in the manual
<a href="http://openmp.llvm.org/Reference.pdf">http://openmp.llvm.org/Reference.pdf</a> (See P3). (Amazing, eh!)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">- Do other compilers targeting libiomp make use of the variable argument array to store the microtask arguments (instead of using a struct of pointers)?</span><br>
<span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D">The intel compiler uses multiple arguments.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D">I’m not sure how much time we’d save by having a specialised entrypoint for the single argument case. (Specialising based on the argument count in the existing
code shouldn’t be very expensive, since it would be one test and perfectly predicted branch).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D">-- Jim<br>
<br>
James Cownie <james.h.cownie@intel.com><br>
SSG/DPD/TCAR (Technical Computing, Analyzers and Runtimes)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D">Tel: +44 117 9071438</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> openmp-dev-bounces@cs.uiuc.edu [mailto:openmp-dev-bounces@cs.uiuc.edu]
<b>On Behalf Of </b>Carlo Bertolli<br>
<b>Sent:</b> Wednesday, June 11, 2014 11:01 PM<br>
<b>To:</b> openmp-dev@dcs-maillist2.engr.illinois.edu<br>
<b>Subject:</b> [Openmp-dev] Number of variable arguments to microtask in __kmp_invoke_microtask<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Hi all,</span><br>
<br>
<span style="font-size:10.0pt;font-family:"Arial","sans-serif"">I noticed that clang generates code with only one "variable argument" to __kmpc_fork_call (i.e. ultimately to __kmp_invoke_microtask) - that is the struct.anon pointer that contains the pointers
to all arguments used in the microtask.</span><br>
<br>
<span style="font-size:10.0pt;font-family:"Arial","sans-serif"">I tried with multiple cases, but I always get the same number of arguments passed to the invoke_microtask function.</span><br>
<br>
<span style="font-size:10.0pt;font-family:"Arial","sans-serif"">- Does anyone know about examples in which more arguments are used? I tried examples which reference a different number of arrays and shared variables, but nothing changes.</span><br>
<br>
<span style="font-size:10.0pt;font-family:"Arial","sans-serif"">- Do other compilers targeting libiomp make use of the variable argument array to store the microtask arguments (instead of using a struct of pointers)?</span><br>
<br>
<span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Thanks for any help</span><br>
<br>
<br>
<span style="font-size:10.0pt;font-family:"Arial","sans-serif"">-- Carlo</span><o:p></o:p></p>
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