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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'>Thanks David for pointing out a mistake in the table! I implemented most of the semantics shown in the table in Alive to test these things, but the bug still slipped through, sorry..<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>I</span><span style='font-size:11.0pt'>’</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>ve updated the table:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p> </o:p></span></p><div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Summary table of what each transformation allows for %z = select %c, %x, %y. Each column is a different alternative of semantics for select:<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></div><table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0 style='border-collapse:collapse'><tr><td width=141 valign=top style='width:105.95pt;border:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></div></td><td width=108 valign=top style='width:81.05pt;border:solid windowtext 1.0pt;border-left:none;padding:0cm 5.4pt 0cm 5.4pt'><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>UB if %c poison<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>+ conditional poison<o:p></o:p></span></p></div></td><td width=128 valign=top style='width:96.1pt;border:solid windowtext 1.0pt;border-left:none;padding:0cm 5.4pt 0cm 5.4pt'><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>UB if %c poison + poison if either<br>%x/%y poison<o:p></o:p></span></p></div></td><td width=128 valign=top style='width:96.1pt;border:solid windowtext 1.0pt;border-left:none;padding:0cm 5.4pt 0cm 5.4pt'><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Conditional poison<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>+ non-det choice if %c poison<o:p></o:p></span></p></div></td><td width=132 valign=top style='width:99.25pt;border:solid windowtext 1.0pt;border-left:none;padding:0cm 5.4pt 0cm 5.4pt'><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Conditional poison + poison if %c poison**<o:p></o:p></span></p></div></td><td width=151 valign=top style='width:4.0cm;border:solid windowtext 1.0pt;border-left:none;padding:0cm 5.4pt 0cm 5.4pt'><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Poison if any of<br>%c/%x/%y are poison<o:p></o:p></span></p></div></td></tr><tr><td width=141 valign=top style='width:105.95pt;border:solid windowtext 1.0pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt'><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>SimplifyCFG<o:p></o:p></span></p></div></td><td width=108 valign=top style='width:81.05pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=128 valign=top style='width:96.1pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></td><td width=128 valign=top style='width:96.1pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=132 valign=top style='width:99.25pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=151 valign=top style='width:4.0cm;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></td></tr><tr><td width=141 valign=top style='width:105.95pt;border:solid windowtext 1.0pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt'><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Select->control-flow<o:p></o:p></span></p></div></td><td width=108 valign=top style='width:81.05pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=128 valign=top style='width:96.1pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=128 valign=top style='width:96.1pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></td><td width=132 valign=top style='width:99.25pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></td><td width=151 valign=top style='width:4.0cm;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></td></tr><tr><td width=141 valign=top style='width:105.95pt;border:solid windowtext 1.0pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt'><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Select->arithmetic<o:p></o:p></span></p></div></td><td width=108 valign=top style='width:81.05pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></td><td width=128 valign=top style='width:96.1pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=128 valign=top style='width:96.1pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></td><td width=132 valign=top style='width:99.25pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>partially <o:p></o:p></span></p></td><td width=151 valign=top style='width:4.0cm;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td></tr><tr><td width=141 valign=top style='width:105.95pt;border:solid windowtext 1.0pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt'><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Select removal<o:p></o:p></span></p></div></td><td width=108 valign=top style='width:81.05pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=128 valign=top style='width:96.1pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=128 valign=top style='width:96.1pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></td><td width=132 valign=top style='width:99.25pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=151 valign=top style='width:4.0cm;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td></tr><tr><td width=141 valign=top style='width:105.95pt;border:solid windowtext 1.0pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt'><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Select hoist<o:p></o:p></span></p></div></td><td width=108 valign=top style='width:81.05pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=128 valign=top style='width:96.1pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=128 valign=top style='width:96.1pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=132 valign=top style='width:99.25pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></td><td width=151 valign=top style='width:4.0cm;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></td></tr><tr><td width=141 valign=top style='width:105.95pt;border:solid windowtext 1.0pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt'><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Easy movement<o:p></o:p></span></p></div></td><td width=108 valign=top style='width:81.05pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></td><td width=128 valign=top style='width:96.1pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> <o:p></o:p></span></p></td><td width=128 valign=top style='width:96.1pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=132 valign=top style='width:99.25pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td><td width=151 valign=top style='width:4.0cm;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=MsoNormal align=center style='text-align:center'><span style='font-size:11.0pt;font-family:"Segoe UI Symbol",sans-serif'>✓</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p></td></tr></table></blockquote></div><div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>IMHO, the 3<sup>rd</sup> and 4<sup>th</sup> options are the ones that work best. Instructions with UB are usually a pain (for e.g. hoisting out of loops).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>An advantage of the 4<sup>th</sup> option is that can partially do select->arithmetic, while the 3<sup>rd</sup> can’t. For example, this is valid with the 4<sup>th</sup> option:<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'><span lang=PT style='font-size:9.0pt;font-family:"Lucida Console"'>%13 = mul nuw i2 %0, -1<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=PT style='font-size:9.0pt;font-family:"Lucida Console"'>%14 = srem i2 %13, -1<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:9.0pt;font-family:"Lucida Console"'>%15 = select i1 %1, i2 1, i2 %14<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:9.0pt;font-family:"Lucida Console"'> =><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:9.0pt;font-family:"Lucida Console"'>%15 = zext i1 %1 to i2<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The 4<sup>th</sup> option, however, can’t do the select->and/or transformations (neither the 3<sup>rd </sup>can).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>That said, I’m inclined to choose the 4<sup>th</sup> option (marked with ** in the table). That’s the one that the online version of Alive implements BTW.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Nuno<o:p></o:p></p></div></div></body></html>