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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Did you fix the errors upstream? If not: can you post a list of the errors you found so others can apply the fixes locally and/or John
(or whoever else is allowed to do it) can fix them in trunk?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">I ran GCC undefinedBehaviourSanitizer some time ago and found some issues which are partly fixed upstream, but missed the one with
the Status enum.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">I am interested how you fixed the integer overflow in the gomory cut generator as John’s fix in trunk just moved the problem a few
lines down causing us to use „-gomory off“ all the time as we are using CBC as a libary and can not risk CBC killing or corrupting the process it runs in. This does not improve performance…<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Tobias<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Von:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Cbc [mailto:cbc-bounces@coin-or.org]
<b>Im Auftrag von </b>Petter Strandmark<br>
<b>Gesendet:</b> Samstag, 21. Oktober 2017 17:09<br>
<b>An:</b> cbc@list.coin-or.org<br>
<b>Betreff:</b> [Cbc] UndefinedBehaviorSanitizer error in OsiPresolvewhen casting Status<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I am compiling and running Cbc with Clang’s UndefinedBehaviorSanitizer. I have been able to fix several errors, but a more tricky one is the following. This line sometimes incorrecly casts an enum:<o:p></o:p></p>
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<p class="MsoNormal"><a href="https://github.com/coin-or/Osi/blob/master/Osi/src/Osi/OsiPresolve.cpp#L505"><br>
</a><o:p></o:p></p>
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<p class="MsoNormal"><a href="https://github.com/coin-or/Osi/blob/master/Osi/src/Osi/OsiPresolve.cpp#L505">https://github.com/coin-or/Osi/blob/master/Osi/src/Osi/OsiPresolve.cpp#L505</a><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">The original enum looks like:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> /*! \brief Enum for status of various sorts</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> </span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> Matches CoinWarmStartBasis::Status and adds superBasic. Most code that</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> converts between CoinPrePostsolveMatrix::Status and</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> CoinWarmStartBasis::Status will break if this correspondence is broken.</span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> superBasic is an unresolved problem: there's no analogue in</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> CoinWarmStartBasis::Status.</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> */</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> enum Status {</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> isFree = 0x00,</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> basic = 0x01,</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> atUpperBound = 0x02,</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> atLowerBound = 0x03,</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> superBasic = 0x04</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> };</span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">and the target enum looks like:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> enum Status {</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> isFree = 0x00, ///< Nonbasic free variable</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> basic = 0x01, ///< Basic variable</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> atUpperBound = 0x02, ///< Nonbasic at upper bound</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> atLowerBound = 0x03 ///< Nonbasic at lower bound</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""> };</span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">UndefinedBehaviorSanitizer stops the execution because the status is superBasic. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">The question is, what is the correct course of action in that case?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Petter<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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