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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:purple">Hi Nadav,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:purple"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:purple">Thanks for your feedback.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:purple"><o:p> </o:p></span></p>
<p class="MsoNormal">>> Thanks for working on this. Can you split the two changes into two patches ? <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Sure. <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">>> Scalarizing PHIs makes sense to me. Does it solve PR11775 ? <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">No. the code sample in 11775 has a phi that doesn’t increment itself directly, as expected by the patch that I provide. It uses some more complex pattern which increments the vector phi indirectly.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">>> Regarding the second change, there is a cost model problem. The existing code converts a vector cast into a scalar cast, which should be profitable for most platforms. However, your transformation creates an additional cast. Why is
it better ? <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m not sure that I follow. The proposed transformation does the same, it creates only one cast. You can see this in the provided test.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">>> I did not read the code but from a quick peek I noticed that the docs are not capitalized and punctuated properly and the variable names are funny, and you left some code commented out and there are extra braces, etc. <o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:purple"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:purple">I made some corrections.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:purple"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:purple">I’m looking forward to get more feedback.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:purple"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:purple">Thanks, Anat
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:purple"><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""> Nadav Rotem [mailto:nrotem@apple.com]
<br>
<b>Sent:</b> Tuesday, April 16, 2013 23:48<br>
<b>To:</b> Shemer, Anat<br>
<b>Cc:</b> llvm-commits@cs.uiuc.edu<br>
<b>Subject:</b> Re: [PATCH] InstCombine: scalarize vector phis<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 Anat, <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thanks for working on this. Can you split the two changes into two patches ? <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Scalarizing PHIs makes sense to me. Does it solve PR11775 ? <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Regarding the second change, there is a cost model problem. The existing code converts a vector cast into a scalar cast, which should be profitable for most platforms. However, your transformation creates an additional cast. Why is it
better ? <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I did not read the code but from a quick peek I noticed that the docs are not capitalized and punctuated properly and the variable names are funny, and you left some code commented out and there are extra braces, etc. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thanks,<o:p></o:p></p>
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<p class="MsoNormal">Nadav<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Apr 16, 2013, at 1:11 PM, "Shemer, Anat" <<a href="mailto:anat.shemer@intel.com">anat.shemer@intel.com</a>> wrote:<o:p></o:p></p>
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<br>
<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Hi,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">I would like to add to InstCombineVectorOps.cpp a function that sclarizes a vector phi instruction if its only use is an extract operation of one element at a constant location.
Such vector phi might be created by the vectorization phase and the generated code is non-optimal.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">In addition, in the function InstCombiner::visitExtractElementInst I removed the limitation that extract is promoted over a cast only if the cast has only one use. To make
this work I replaced the use of Builder->CreateExtractElement() call with InsertNewInstWith(ExtractElementInst::Create()..), which also inserts the new instruction into the worklist.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">I also added a test for these 2 cases.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">I will appreciate your feedback.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Thanks, Anat<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","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""> </span><span style="font-size:10.0pt;font-family:"Verdana","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""> </span><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""><o:p></o:p></span></p>
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