<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 Jul 1, 2013, at 6:14 PM, Chandler Carruth <<a href="mailto:chandlerc@google.com">chandlerc@google.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div class="gmail_extra" style="font-family: Helvetica; font-size: 12px; 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;">If we want to define an IR construct to express multidimensional array references without linearizing, I suspect we would need a very different / new instruction... retrofitting GEP seems risky given its existing uses and complexity. If you or other folks have ideas of how to represent this effectively in LLVM's IR, by all means fire away. =]</div><div class="gmail_extra" style="font-family: Helvetica; font-size: 12px; 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;"><br></div><div class="gmail_extra" style="font-family: Helvetica; font-size: 12px; 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;"><br></div><div class="gmail_extra" style="font-family: Helvetica; font-size: 12px; 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;">Personally, I think it would be useful to at see if we could at least delinearize "obvious" or "easy" cases. We might actually get reasonably good mileage out of this. However, my perspective here is biased -- I work almost exclusively with a language that doesn't provide the guarantees Fortran does regarding multidimensional arrays.</div></blockquote></div><div><br></div>Agreed. We should find out which important cases cannot be successfully delinearized without further IR annotation and only then think about extending IR.<div><br></div><div>-Andy</div></body></html>