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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Hi All,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’m looking into converting LICM to use MemorySSA instead of AliasSets to determine when it is safe to hoist/sink/promote loads and stores to get around the issue of alias set collapse (see discussion [1]). I have a prototype implementation, but have run into two issues that I could use input from the designers of MemorySSA to resolve:<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>1)<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>Is MemorySSA intended to be maintained across passes? More specifically how is it intended to interact with the Pass Manager? In my current prototype I’m just building it at the start of LICM.<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>2)<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>What is the intended method for dealing with changes to the function that invalidate the MemorySSA form? I see that there is a way to remove nodes from the MemorySSA graph, but for other transformations (e.g. hoisting a load) am I supposed to just update the MemorySSA graph myself?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>[1] http://lists.llvm.org/pipermail/llvm-dev/2015-April/084881.html<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div style='mso-element:para-border-div;border:dashed #2F6FAB 1.0pt;padding:12.0pt 12.0pt 12.0pt 12.0pt;background:#F9F9F9'><p class=MsoNormal style='line-height:15.6pt;background:#F9F9F9;border:none;padding:0in'>--<o:p></o:p></p><p class=MsoNormal style='line-height:15.6pt;background:#F9F9F9;border:none;padding:0in'>Geoff Berry<o:p></o:p></p><p class=MsoNormal style='line-height:15.6pt;background:#F9F9F9;border:none;padding:0in'>Employee of Qualcomm Innovation Center, Inc.<o:p></o:p></p><p class=MsoNormal style='line-height:15.6pt;background:#F9F9F9;border:none;padding:0in'> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project<o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p></div></body></html>