<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">
Dear Clang/BGQ folks,
<div class=""><br class="">
</div>
<div class="">We encounter a problem with certain parts of our C++ code when using higher-level optimizations (-On with n>1) with clang on JUQUEEN. I was able to boil down the problem to being apparently linked to the “-inline” optimization pass. When I compile
with “-O3” or “-O2” and also use the “-fno-inline” option afterwards, execution works as expected.</div>
<div class=""><br class="">
</div>
<div class="">The problem only seems to occur on the BG/Q machine as we use the same flags everywhere and it does work on e.g. our institute’s cluster. Therefore my questions are</div>
<div class=""><br class="">
</div>
<div class="">a) Have you encountered a similar problem on BG/Q? If yes, how did you manage to resolve it?</div>
<div class="">b) What would be the best way to identify and fix the offending lines in our code (assuming that it can be fixed/reduced to a handful of locations)?</div>
<div class=""><br class="">
</div>
<div class="">Thanks a lot!</div>
<div class=""><br class="">
</div>
<div class="">Michael</div>
<div class=""><br class="">
</div>
<div class="">P.S.: Since I have a good idea in which file the error is located, I tried to fix the location by just specifying </div>
<div class=""><br class="">
</div>
<div class="">#pragma clang optimize off</div>
<div class=""><br class="">
</div>
<div class="">at the beginning of a source file. This, however, led to a compiler crash (see <a href="http://llvm.org/bugs/show_bug.cgi?id=22664" class="">http://llvm.org/bugs/show_bug.cgi?id=22664</a>), so I could not investigate this issue further.</div>
<br class="">
<br class="">
<div apple-content-edited="true" class=""><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; ">
<div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; " class="">
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; ">
<div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; " class="">
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; ">
<div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; " class="">
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; ">
<div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; " class="">
--<br class="">
Michael Schlottke<br class="">
<br class="">
</div>
<div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; " class="">
SimLab Highly Scalable Fluids & Solids Engineering<br class="">
Jülich Supercomputing Centre (JSC)<br class="">
Forschungszentrum Jülich GmbH<br class="">
52425 Jülich<br class="">
Germany<br class="">
<br class="">
Phone: +49 (2461) 61 2326<br class="">
Mail: <a href="mailto:m.schlottke@fz-juelich.de" class="">m.schlottke@fz-juelich.de</a><br class="">
Web: <a href="http://www.fz-juelich.de/jsc" class="">http://www.fz-juelich.de/jsc</a></div>
</span></div>
</span></div>
</span></div>
</span></span></div>
<br class="">
<br>
<font face="Arial" color="Black" size="1"><br>
------------------------------------------------------------------------------------------------<br>
------------------------------------------------------------------------------------------------<br>
Forschungszentrum Juelich GmbH<br>
52425 Juelich<br>
Sitz der Gesellschaft: Juelich<br>
Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498<br>
Vorsitzender des Aufsichtsrats: MinDir Dr. Karl Eugen Huthmacher<br>
Geschaeftsfuehrung: Prof. Dr.-Ing. Wolfgang Marquardt (Vorsitzender),<br>
Karsten Beneke (stellv. Vorsitzender), Prof. Dr.-Ing. Harald Bolt,<br>
Prof. Dr. Sebastian M. Schmidt<br>
------------------------------------------------------------------------------------------------<br>
------------------------------------------------------------------------------------------------<br>
<br>
</font>
</body>
</html>