<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Hi All,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">  The comment of UNDEF in ISDOpcodes.h [1] is pretty simple,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">







<p class="gmail-p1"><span class="gmail-s1">      /// UNDEF - An undefined node.</span></p><p class="gmail-p1">      UNDEF,</p></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">The name make me think of C undefined behavior, which is ... scary. But I also see there are</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">APIs like isBuildVectorAllOnes, isBuildVectorAllZeros, ... etc, seems UNDEF just can be any</font><br></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">value and we don't care about what it is. The most case I see UNDEF is in BUULD_VECTOR,</font></div><div class="gmail_default"><span style="color:rgb(0,0,0);font-family:Roboto,sans-serif;font-size:14px;white-space:nowrap">VECTOR_SHUFFLE</span><font face="arial, helvetica, sans-serif">, ... etc. I would like to know usually how we deal with those UNDEF nodes?</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif"><br></font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">Thanks.</font></div><div class="gmail_default"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">[1] <a href="http://llvm.org/doxygen/ISDOpcodes_8h_source.html">http://llvm.org/doxygen/ISDOpcodes_8h_source.html</a></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Regards,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">chenwj</div><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><div>Wei-Ren Chen (陳韋任)<br>Homepage: <a href="https://people.cs.nctu.edu.tw/~chenwj" target="_blank">https://people.cs.nctu.edu.tw/~chenwj</a></div></div></div>
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