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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>I’ve attached a 2 examples of patterns for updating an array. They’re simplified examples of some code generation I’m doing where I need to pass a large, unknown number of arguments (ints, doubles, pointers to other information) to a function.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The two patterns are:<o:p></o:p></p><p class=MsoNormal> Stack[0] = 0;<o:p></o:p></p><p class=MsoNormal> Stack[1] = 1;<o:p></o:p></p><p class=MsoNormal> Stack[2] = 42;<o:p></o:p></p><p class=MsoNormal>And<o:p></o:p></p><p class=MsoNormal> Int I = 0;<o:p></o:p></p><p class=MsoNormal> Stack[i++] = 0;<o:p></o:p></p><p class=MsoNormal> Stack[i++] = 1;<o:p></o:p></p><p class=MsoNormal> Stack[i++] = 42;<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’ve found that the optimizer is much faster at handling the 2<sup>nd</sup> pattern than the 1<sup>st</sup>. With 3000 assignments - as in the examples attached – “opt –std-compile-opts –S func1.ll –o func1.opt” takes 10 seconds, while func2.ll takes 0.2s. Anyone have any ideas why?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’ve tested with LLVM 2.9, and LLVM 3.0 RC1.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Regards,<o:p></o:p></p><p class=MsoNormal>Michael<o:p></o:p></p></div></body></html>