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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hi James,<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'>I think there are two main reasons this approach is outside of CGP:<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>(1)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I want to make use of the constant extraction logic in SeparateConstOffsetFromGEP pass. It can find more constants <o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>(2)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>CGP only sinks GEPs, it doesn’t do CSE. So I think it’s better to do such logic separately in SeparateConstOffsetFromGEP pass before CGP. This won’t affect the address sinking logic in CGP.<o:p></o:p></span></p><p class=MsoListParagraph><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'>-Hao<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><div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><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"'> mankeyrabbit@gmail.com [mailto:mankeyrabbit@gmail.com] <b>On Behalf Of </b>James Molloy<br><b>Sent:</b> Wednesday, October 22, 2014 4:01 AM<br><b>To:</b> reviews+D5864+public+2de5fd757ea4c578@reviews.llvm.org<br><b>Cc:</b> Hao Liu; t.p.northover@gmail.com; jingyue@google.com; llvm-commits@cs.uiuc.edu<br><b>Subject:</b> Re: [PATCH] [AArch64] Improve and enable the SeparateConstOffsetFromGEP for AArch64 backend.<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Hi Hao,<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>It's great to finally see this go upstream!<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>When you started working on this, the approach was to modify the GEP lowering logic in CGP. Hal's comment has reminded me that your approach has moved away from that, so could you please explain why you're doing this outside of CGP, and why your solution does not duplicate the CGP lowering code?<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>How do they interact?<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Cheers,<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>James<o:p></o:p></p></div><div><p class=MsoNormal><br>On Tuesday, 21 October 2014, <a href="mailto:hfinkel@anl.gov">hfinkel@anl.gov</a> <<a href="mailto:hfinkel@anl.gov">hfinkel@anl.gov</a>> wrote:<o:p></o:p></p><p class=MsoNormal>> And most important is that it will also transform complex GEPs into a "ptrtoint + arithmetic + inttoptr" form, so that it is able to find CSE opportunities across basic blocks.<br><br>You'll need to disable this transformation when AA is enabled in CodeGen. You can do this just like CGP does (essentially by calling TM->getSubtarget<TargetSubtargetInfo>().useAA()). CGP splits the GEPs into simpler GEPs when AA is in use, and uses inttoptr otherwise. This all relates to the way that we use BasicAA to override TBAA and catch cases of basic type punning -- but BasicAA does not analyze inttoptr, and so can no longer fulfill this need after new inttoptrs are introduced. You could try using simpler GEPs like CGP does when AA is in use, or just disable this part of the transformation for now. Either is fine with me.<br><br><a href="http://reviews.llvm.org/D5864" target="_blank">http://reviews.llvm.org/D5864</a><br><br><br><br>_______________________________________________<br>llvm-commits mailing list<br><a href="javascript:;">llvm-commits@cs.uiuc.edu</a><br><a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits" target="_blank">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</a><o:p></o:p></p></div></div></div></body></html>