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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Mehdi,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> Many thanks, this really helps me understand “the llvm way”<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">--Peter Lawrence.<o:p></o:p></span></p>
<p class="MsoNormal"><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"><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"> mehdi.amini@apple.com [mailto:mehdi.amini@apple.com]
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<b>Sent:</b> Thursday, July 14, 2016 10:58 AM<br>
<b>To:</b> Lawrence, Peter <c_plawre@qca.qualcomm.com><br>
<b>Cc:</b> vivek pandya <vivekvpandya@gmail.com>; llvm-dev <llvm-dev@lists.llvm.org>; llvm-dev-request@lists.llvm.org; Hal Finkel <hfinkel@anl.gov><br>
<b>Subject:</b> Re: [llvm-dev] IPRA, interprocedural register allocation, question<o:p></o:p></span></p>
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<p class="MsoNormal">Just to clarify, because I don't know your exact build flow, LLVM has the internalize pass that can turn all (controlled with a whitelist optionally) symbols static without having to change the source.<o:p></o:p></p>
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<p class="MsoNormal">-- <o:p></o:p></p>
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<p class="MsoNormal">Mehdi<br>
<br>
Sent from my iPhone<o:p></o:p></p>
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On Jul 14, 2016, at 10:48 AM, Lawrence, Peter <<a href="mailto:c_plawre@qca.qualcomm.com">c_plawre@qca.qualcomm.com</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">Mehdi,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> Bravo, Well done Mr Amini !</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Ordinarily I would find adding “static” to all functions objectionable,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">We’re doing whole-program compilation and optimization, and don’t</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">use a linker, so “static” currently doesn’t appear anywhere in our sources.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">And I view “static” as not really part of the language, rather more</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">of a linker directive. But we really only have a small handful of real-time</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">performance critical functions, it will be trivial to declare them static.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">--Peter Lawrence.</span><o:p></o:p></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">
<a href="mailto:mehdi.amini@apple.com">mehdi.amini@apple.com</a> [<a href="mailto:mehdi.amini@apple.com">mailto:mehdi.amini@apple.com</a>]
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<b>Sent:</b> Wednesday, July 13, 2016 12:42 PM<br>
<b>To:</b> Lawrence, Peter <<a href="mailto:c_plawre@qca.qualcomm.com">c_plawre@qca.qualcomm.com</a>><br>
<b>Cc:</b> vivek pandya <<a href="mailto:vivekvpandya@gmail.com">vivekvpandya@gmail.com</a>>; llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>>;
<a href="mailto:llvm-dev-request@lists.llvm.org">llvm-dev-request@lists.llvm.org</a>; Hal Finkel <<a href="mailto:hfinkel@anl.gov">hfinkel@anl.gov</a>><br>
<b>Subject:</b> Re: [llvm-dev] IPRA, interprocedural register allocation, question</span><o:p></o:p></p>
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<p class="MsoNormal">On Jul 13, 2016, at 12:40 PM, Mehdi Amini <<a href="mailto:mehdi.amini@apple.com">mehdi.amini@apple.com</a>> wrote:<o:p></o:p></p>
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On Jul 13, 2016, at 12:26 PM, Lawrence, Peter <<a href="mailto:c_plawre@qca.qualcomm.com">c_plawre@qca.qualcomm.com</a>> wrote:</span><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">Vivek,</span><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"> I apologize if you took my original email as a request for implementation,</span><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">I meant to be asking what is already available, I think the answer to that</span><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">is the ‘preserves_most’ and ‘preserves_all’ attributes, but I will also</span><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">Use ‘regmask’ if those prove to be too sub-optimal.</span><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">I am still interested in figuring out the necessary and sufficient conditions</span><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">For LLC to do optimal IPRA when given a “whole program”</span><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">(as per my previous definition of “whole program”),</span><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">As opposed to how to accomplish this with LTO,</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif">Easy: mark *all* of your function “static” (or “internal” in LLVM denomination). </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
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