<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;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On May 6, 2017, at 10:39 PM, Brent Royal-Gordon <<a href="mailto:brent@architechies.com" class="">brent@architechies.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=us-ascii" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><blockquote type="cite" class=""><div class="">On May 6, 2017, at 10:34 PM, Daniel Dunbar via swift-users <<a href="mailto:swift-users@swift.org" class="">swift-users@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">To answer Kelvin's question, yes, the optimizer will be able to see through that code _assuming_ it can see the definition in a way it can optimize</span></div></blockquote></div><div class=""><br class=""></div><div class="">Kelvin, you should definitely take Daniel's word over mine on whether there's an optimization for this. I believe the rest of my explanation is correct.</div></div></div></blockquote><div><br class=""></div>Actually I think yours was more accurate... while it is is true the desired optimization will often take effect (given the conditions I describe), your's was correct that this isn't happening because the function signature is taking _fewer_ arguments. Rather, the optimizations works because the compiler will tend to inline that small function and then see it can discard the unnecessary data.</div><div><br class=""></div><div>Whether or not this makes it worth boxing your struct to avoid large copies probably depends on how much you need to pass the struct through call sites which would in fact need to copy the full struct, versus inlining down to something smaller.</div><div><br class=""></div><div>HTH,</div><div> - Daniel</div><div><br class=""></div><div><blockquote type="cite" class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div class="">
<span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-variant-east-asian: normal; font-variant-position: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; border-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-stroke-width: 0px;"><div class=""><div style="font-size: 12px; " class="">-- </div><div style="font-size: 12px; " class="">Brent Royal-Gordon</div><div style="font-size: 12px; " class="">Architechies</div></div></span>
</div>
<br class=""></div></div></blockquote></div><br class=""></body></html>