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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Could I get a review/comment on this patch?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Tyler<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> llvm-commits-bounces@cs.uiuc.edu [mailto:llvm-commits-bounces@cs.uiuc.edu]
<b>On Behalf Of </b>Nowicki, Tyler<br>
<b>Sent:</b> Thursday, February 14, 2013 6:44 PM<br>
<b>To:</b> Chris Lattner<br>
<b>Cc:</b> llvm-commits@cs.uiuc.edu<br>
<b>Subject:</b> RE: [PATCH][Review Requested][Compilation Time] Using hashing in getVTList()<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Hi Chris,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Thanks for the review. We have committed the const change.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">FoldingSet – We have experimented with using FoldingSet on another compile-time optimization however we found that it was slower. Sriram Murali posted a message
discussing our findings on this. See `RE: [PATCH][Review Requested][Compilation Time] Calculate hash value and equality comparison within SCEV node itself’<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Hashing – The patch uses bucket hashing. It is simple and fast. Can you suggest something better?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Tyler<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Chris Lattner [<a href="mailto:clattner@apple.com">mailto:clattner@apple.com</a>]
<br>
<b>Sent:</b> Wednesday, February 13, 2013 12:05 AM<br>
<b>To:</b> Nowicki, Tyler<br>
<b>Cc:</b> <a href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
<b>Subject:</b> Re: [PATCH][Review Requested][Compilation Time] Using hashing in getVTList()<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Jan 31, 2013, at 2:54 PM, "Nowicki, Tyler" <<a href="mailto:tyler.nowicki@intel.com">tyler.nowicki@intel.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Hi,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">This patch aims to improve compile time performance by replacing a sequential search over an std::vector in the function getVTList() with a look up into a SmallVector where
the index is calculated by hashing the input VTs and a sequential search through a smaller VT bucket.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">This patch is part of a series of compile time improvements. Although these were originally produced by our colleague Wan Xiaofei, our team consisting of<span class="apple-converted-space"> </span><a href="mailto:preston.gurd@intel.com"><span style="color:purple">preston.gurd@intel.com</span></a>;<a href="mailto:sriram.murali@intel.com"><span style="color:purple">sriram.murali@intel.com</span></a><span class="apple-converted-space"> </span>and
myself, are assuming all responsibility for this work.<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hi Tyler,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Marking stuff const is obvious, please commit that. For the actual algorithm here, have you considered using a FoldingSet or a hash table of some sort to unique the lists instead of switching the order of the linear scan?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">-Chris<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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