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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link=blue vlink=purple><div class=WordSection1><div><p class=MsoNormal>On 5 June 2013 13:32, David Tweed <<a href="mailto:david.tweed@arm.com" target="_blank">david.tweed@arm.com</a>> wrote:<o:p></o:p></p><div><div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm'><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>This is what I'd like to know about: what specific potential to change results have you seen in the vectorizer?</span><o:p></o:p></p></div></div></blockquote></div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-family:Wingdings;color:#1F497D'><span style='mso-list:Ignore'>Ř<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]>No changes, just conceptual. AFAIK, the difference between the passes on O2 and O3 are minimal (looking at the code where this is chosen) and they don't seem to be particularly amazing to warrant their special place in On land.<o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div><div><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-family:Wingdings;color:#1F497D'><span style='mso-list:Ignore'>Ř<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]>If the argument for having auto-vec on O2 is that O3 makes no difference, than, why have O3 in the first place? Why not make O3 an alias to O2 and solve all problems?<o:p></o:p></p></div><div><p class=MsoNormal><span style='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 I'm managing to express myself unclearly again </span><span style='font-size:11.0pt;font-family:Wingdings;color:#1F497D'>L</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> For me the practical definition of "O2" is "do transformations which are pretty much guaranteed to actually be optimizations" rather than "do all optimizations which don't carry a risk of disaster". In which case the argument for or against vectorizing at O2 is whether it's " pretty much guaranteed to actually be an optimization" or not rather than whether it's an aggressive optimization or not. I wouldn't say the argument for auto-vec on O2 isn't that O3 makes no difference, it's whether the intrinsic properties of auto-vec pass fit with the criteria which one uses for enabling passes at O2. I think you were suggesting that "aggressive" transforms don't belong in O2 and auto-vec is "aggressive", while I tend to think of simplicity/performance-relaiblity as the criteria for O2 and it's unclear if auto-vec fits that.<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'>Cheers,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dave<o:p></o:p></span></p></div></div></div></body></html>