<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 Apr 21, 2013, at 6:58 AM, Hal Finkel <<a href="mailto:hfinkel@anl.gov">hfinkel@anl.gov</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span 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; float: none; display: inline !important;">Regarding vectorizing vectors, should there be a FIXME?</span><br 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></blockquote><br></div><div>Hi Hal, </div><div><br></div><div>We may want to add support for vectorizing vectors, but this is a low priority for me now. There are two possible sources of vectors: user code and the loop vectorizer. The Loop Vectorizer has a cost model and should produce optimal vector code. Users who vectorize their code using vector builtins/intrinsics usually know what they are doing and will probably not benefit from auto-vectorization. The only exception that I can think of is migrating user code to new ISA which has wider vector units. For example, the move from SSE to AVX. Can you think of another motivation for re-vectorizing ?</div><div><br></div><div>Thanks,</div><div>Nadav </div><br></body></html>