<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On Feb 17, 2013, at 1:15 PM, Hal Finkel <<a href="mailto:hfinkel@anl.gov">hfinkel@anl.gov</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><blockquote type="cite" style="font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; ">Unrolling OTOH should be aware of and preserve any loop metadata.<br></blockquote><br style="font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><span style="font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; display: inline !important; float: none; ">If the unroller somehow differentiates the metadata coming from different loop iterations, then BBVectorize can use this information as well. Even better, we could make BasicAA understand that appropriately marked loads and stores from different iterations don't alias. Then the AA-based dependency breaker in the scheduler could also make use of the information. Thoughts?</span></blockquote></div><br><div>That could work. Eventually the LoopVectorizer pass should be able to unroll and overlap iterations. If then it's still important for BBVectorize to disambiguate, that information could be provided either by updating the metadata or a separate analysis preserved by LoopVectorizer. BBVectorize should run immediately afterward.</div><div><br></div><div>-Andy</div></body></html>