<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Mar 5, 2015, at 10:33 PM, Nema, Ashutosh <<a href="mailto:Ashutosh.Nema@amd.com" class="">Ashutosh.Nema@amd.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="WordSection1" style="page: WordSection1; font-family: Helvetica; font-size: 10px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">I am about to post the patches to make LAA suitable for Loop Distribution. As you will hopefully find this will make the LAA more generic. I will cc you on the patches.<o:p class=""></o:p></div><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""> </span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">Sure Adam.<o:p class=""></o:p></span></div></div><blockquote style="margin-top: 5pt; margin-bottom: 5pt;" class=""><div class=""><div class=""><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><b class="">RuntimeCheckEmitter</b><o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">“RuntimeCheckEmitter::addRuntimeCheck”<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">While creating runtime check I have found, some of the things are not getting considered.<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">1) No need to check if two read only pointers intersect.<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">2) Only need to check pointers between two different dependency sets.<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">3) Only need to check pointers in the same alias set<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">I’m sure if we like this to be used by other optimization then not all optimization appreciate<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">above checks. Specifically LoopVersioning does not care about this, it expects all the pointers<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">in a loop should be considered for a memory check. Also it does not care about different<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">dependency set & different alias sets.<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">I suggest we can make these checks optional, and give flexibility to users of this class to set it.<o:p class=""></o:p></div></div></div></blockquote><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">I am not sure I follow. The logic is meant to reduce the number of memory checks necessary to ensure the independence of may-alias accesses. We can omit 1-3 but then we would end up with unnecessary checks that could unnecessarily slow things down.<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="color: rgb(31, 73, 125);" class=""> </span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""> </span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="color: rgb(31, 73, 125);" class="">I just wanted to keep a flexibility open.<o:p class=""></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="color: rgb(31, 73, 125);" class="">We can give a try to LoopVersioning by keeping point 1 & 3 checks. but I’m not sure about point 2.<o:p class=""></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="color: rgb(31, 73, 125);" class="">Will give a try to your upcoming patch.<o:p class=""></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""> </span></div></div><blockquote style="margin-top: 5pt; margin-bottom: 5pt;" class=""><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><b class="">LoopAccessAnalysis::analyzeLoop</b><o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Here again its very specific to LoopVectorizer.<span class="apple-converted-space"> </span><o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">The way it handles stores & loads may not be appreciated by other optimization<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">expecting other treatment. I suggest we should think on flexibility for user to<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">override load & store handling. We can provide virtual methods for load & store<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">handling (i.e. analyzeLoads & analyzeStores). Also some of the optimization may not<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">like call instruction, or further they like to analyze call. We should also think on those<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">lines to make some provision.<o:p class=""></o:p></div></div></blockquote><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Can you please elaborate how you want to analyze function calls?<o:p class=""></o:p></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="color: rgb(31, 73, 125);" class="">For calls expecting overridable method, providing flexibility to user to redefine behavior.<o:p class=""></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="color: rgb(31, 73, 125);" class="">There are few possible cases:<o:p class=""></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="color: rgb(31, 73, 125);" class="">may not like any call in the loop body, or may like only few specific calls.<o:p class=""></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="color: rgb(31, 73, 125);" class="">or may not like to pass any pointer/address out of loop by calls.<o:p class=""></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="color: rgb(31, 73, 125);" class=""> </span></div><blockquote style="margin-top: 5pt; margin-bottom: 5pt;" class=""><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">AccessAnalysis & LoopAccessAnalysis are tied up dependency check, If some analysis<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">needs same functionality except dependency check then there should be provision available.<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">i.e. LoopVersioning needs similar stuff except dependency analysis, for now possibility is<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">extend & rewrite functions by removing dependency checks.<span class="apple-converted-space"> </span><o:p class=""></o:p></div></div></blockquote><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt 0.5in; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">I actually consider the coupling of dependency analysis and memcheck generation as a feature. Since dependence analysis can further disambiguate memory accesses (as in the DependencySet except you mentioned above) it can reduce the number of run-time memory checks necessary.<o:p class=""></o:p></div></div><div class=""><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="color: rgb(31, 73, 125);" class="">As mentioned above I’m not sure this will be useful for loopVersioning.<o:p class=""></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">But like to give a try with your upcoming patch.</span></div></div></div></div></blockquote><div><br class=""></div><div>Hi Ashutosh,</div><div><br class=""></div><div>My changes are committed now. LoopAccessAnalysis is an analysis pass, so it has the advantage that the result of the analysis is cached until it gets invalidated (i.e. when the loop changes).</div><div><br class=""></div><div>For an example of how to use it, you can look at either the loop-vectorizer in the tree or the WIP patch for the loop-distribution pass in <a href="http://reviews.llvm.org/D6930" class="">http://reviews.llvm.org/D6930</a>.</div><div><br class=""></div><div>Please let me know if you have any questions.</div><div><br class=""></div><div>Adam</div><div><br class=""></div><blockquote type="cite" class=""><div class=""><div class="WordSection1" style="page: WordSection1; font-family: Helvetica; font-size: 10px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div class=""><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""><o:p class=""></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""> </span></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><br class=""><span style="color: rgb(31, 73, 125);" class="">Thanks,</span><o:p class=""></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">Ashutosh</span></div></div></div></blockquote></div><br class=""></body></html>