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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">I’m using trunk version of both libstdc++ and libc++.<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Marshall Clow <mclow.lists@gmail.com>
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<b>Sent:</b> Tuesday, August 27, 2019 12:37 AM<br>
<b>To:</b> Yan Yichen <yichen.yan@inf.ethz.ch><br>
<b>Cc:</b> libcxx-dev@lists.llvm.org<br>
<b>Subject:</b> Re: [libcxx-dev] libcxx performance issue<o:p></o:p></span></p>
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<p class="MsoNormal">On Mon, Aug 26, 2019 at 3:36 PM Marshall Clow <<a href="mailto:mclow.lists@gmail.com">mclow.lists@gmail.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal">On Sat, Aug 24, 2019 at 11:28 AM Yan Yichen via libcxx-dev <<a href="mailto:libcxx-dev@lists.llvm.org" target="_blank">libcxx-dev@lists.llvm.org</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Dear developers,</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> Sorry to bother you, but I’ve met a wired problem using clang with libcxx.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> I’ve built clang and libcxx with clang, and trying to compile c++ program with libc++, but compilation is extremely slow when using libcxx, as below:</span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">$ time clang++ -o /dev/null -std=c++11 -stdlib=libc++ test.cc</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">clang++ -o /dev/null -std=c++11 -stdlib=libc++ test.cc 4.29s user 0.06s system 97% cpu 4.476 total</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">$ time clang++ -o /dev/null -std=c++11 test.cc</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">clang++ -o /dev/null -std=c++11 test.cc 1.41s user 0.06s system 92% cpu 1.582 total</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> I wonder if you have any idea where should I start to address this issue, or anything I probably configured wrong? Thanks in advanced.</span><o:p></o:p></p>
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<p class="MsoNormal">I'm afraid I have no idea what you're comparing *with*.<o:p></o:p></p>
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<p class="MsoNormal">Or rather, comparing *against*.<o:p></o:p></p>
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<p class="MsoNormal">What are you using when you're not using libc++?<o:p></o:p></p>
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<p class="MsoNormal">-- Marshall<o:p></o:p></p>
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