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<p style="margin-top:0;margin-bottom:0">Hi Philip,</p>
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<p style="margin-top:0;margin-bottom:0">I would like to try different pass sequences with opt and see how they affect program optimization, and I was thinking replicating the O3 sequence would be a start point. </p>
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<p style="margin-top:0;margin-bottom:0">Thanks,</p>
<p style="margin-top:0;margin-bottom:0">Han</p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Philip Pfaffe <philip.pfaffe@gmail.com><br>
<b>Sent:</b> 21 October 2018 11:36:07<br>
<b>To:</b> Han Cui<br>
<b>Cc:</b> llvm-dev<br>
<b>Subject:</b> Re: [llvm-dev] Replication -O3 optimizations manually</font>
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<div>Hi Han,</div>
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What is your ultimate goal here?
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<div>Cheers,</div>
<div>Philip</div>
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<div dir="ltr">On Fri, Oct 19, 2018 at 9:17 PM Han Cui via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>> wrote:<br>
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<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif">Hi,<u></u><u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif"><u></u> <u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif">I’m having a very similar question to
<a href="http://lists.llvm.org/pipermail/llvm-dev/2018-August/125416.html" target="_blank">
this thread</a>, about replicating the O3 optimization processing manually using opt.
<u></u><u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif"><u></u> <u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif">This is my setup:<u></u><u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif"><u></u> <u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif">Process A:<u></u><u></u></span></p>
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<span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif">clang -O1 -S -emit-llvm main.c -o main.ll<u></u><u></u></span></li><li class="x_m_-4633289030068696578MsoListParagraph" style="color:black; margin-left:0cm">
<span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif">opt -O3 main.ll -o main-opt1.ll<u></u><u></u></span></li><li class="x_m_-4633289030068696578MsoListParagraph" style="color:black; margin-left:0cm">
<span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif">clang -O1 main-opt1.ll -o main-opt1<u></u><u></u></span></li></ol>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif; color:black"><u></u> <u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif">Process B:<u></u><u></u></span></p>
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<li class="x_m_-4633289030068696578MsoListParagraph" style="color:black; margin-left:0cm">
<span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif">clang -O1 -S -emit-llvm main.c -o main.ll<u></u><u></u></span></li></ol>
<pre style="margin-left:36.0pt"><u></u><span style="color:black"><span>2.<span style="font:7.0pt "Times New Roman""> </span></span></span><u></u><span style="font-family:"Calibri Light",sans-serif; color:black">opt [opt flags given by command ‘opt -O3 -disable-output -debug-pass=Arguments main.ll’] main.ll -o main-opt2.ll<u></u><u></u></span></pre>
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<li class="x_m_-4633289030068696578MsoListParagraph" style="color:black; margin-left:0cm">
<span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif">clang -O1 main-opt2.ll -o main-opt2<u></u><u></u></span></li></ol>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif; color:black"><u></u> <u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif; color:black">I tried this with a set of programs and I noticed the execution time of main-opt2 is often much slower than main-opt1. While ‘main.ll’ is the same, ‘main-opt1.ll’
is different to ‘main-opt2.ll’. May I get some suggestions what I should put for opt (to replace the command in the brackets), so that the two process would have identical effects? Any help would be much appreciated.
<u></u><u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif; color:black"><u></u> <u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif; color:black">Thanks,<u></u><u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif; color:black">Han<u></u><u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif; color:black"><u></u> <u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif; color:black"><u></u> <u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:10.0pt; font-family:"Calibri Light",sans-serif"><u></u> <u></u></span></p>
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