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<p class="MsoNormal"><span style="color:#1F497D">This has come up recently, and I thought changes got committed to add that pass. Maybe it’s happening somewhere else?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">-Andy<o:p></o:p></span></p>
<p class="MsoNormal"><span style="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>Bader, Aleksey A<br>
<b>Sent:</b> Tuesday, April 01, 2014 6:52 AM<br>
<b>To:</b> llvm-commits@cs.uiuc.edu<br>
<b>Subject:</b> Missing analysis in MCJIT?<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It looks like MCJIT::emitObject is missing target specific analysis passes to do efficient code generation.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Codegen runs several preparation passes including Loop Strength Reduction, which hoists some computations out of the loop increasing register pressure, which leads to register spills on 32-bit platform. In order to estimate the profitability
of the modification this pass uses TargetTransformInfo analysis data. My understanding is that NoTargetTransformInfo pass is created by default and it is not good enough for efficient code generation. This fix introduces target-specific passes, which provide
correct cost of modifications.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Does it make sense?<o:p></o:p></p>
<p class="MsoNormal">- Alexey<o:p></o:p></p>
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