<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=""><div><blockquote type="cite" class=""><div class="">On Nov 2, 2017, at 4:35 PM, Johannes Weiß via swift-dev <<a href="mailto:swift-dev@swift.org" class="">swift-dev@swift.org</a>> wrote:</div><div class=""><blockquote type="cite" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" class="">On 2 Nov 2017, at 1:33 pm, Erik Eckstein <<a href="mailto:eeckstein@apple.com" class="">eeckstein@apple.com</a>> wrote:<br class=""><br class=""><br class=""><br class=""><blockquote type="cite" class="">On Nov 2, 2017, at 10:51 AM, Johannes Weiß <<a href="mailto:johannesweiss@apple.com" class="">johannesweiss@apple.com</a>> wrote:<br class=""><br class="">Definitely a +1 from me, a haven't recently seen much of a difference either.<br class=""><br class="">Said that I do sometimes use it in a micro-benchmark just to convince myself we don't lose much performance on the checks. Usually it turns out fine, I'm happy and move on. But I guess there's some value in being able to elide a lot of checks just to see how much of a difference it does. And if there's a big difference then I'd try to optimise the program and elide unnecessary checks myself. Clearly -Ounchecked should never be used in any real code but I find having a baseline when optimising performance very helpful and -Ounchecked sometimes seemed like a cheap, automatic baseline for some code ;).<br class=""><br class="">And lastly I always thought having it as an 'optimisation' is a misnomer, it's not an optimisation as it clearly changes the semantics of the program quite a bit. I thought '-unsafe-remove-checks' or something describes it better, a bit like '-assume-single-threaded’.<br class=""></blockquote><br class="">I like that idea. We could add such an option.<br class=""></blockquote><br 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;" 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="">awesome, that's be a +💯 from me then 🙂</span><br 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;" class=""></div></blockquote><div><br class=""></div><div>Yeah, if the proposal is really just to provide a separate option for turning off safety checks instead of conflating it into the -O option, that seems totally unobjectionable.</div><div><br class=""></div><div>John.</div><br class=""><blockquote type="cite" class=""><div class=""><br 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;" class=""><blockquote type="cite" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" class=""><br class="">Daniel, I think that’s also what you were asking for.<br class=""><br class=""><br class=""><blockquote type="cite" class="">But probably the 'no checks' mode adds too much complexity to just keep it around for a questionable way to do performance baselines.<br class=""><br class=""><blockquote type="cite" class="">On 2 Nov 2017, at 9:52 am, Erik Eckstein via swift-dev <<a href="mailto:swift-dev@swift.org" class="">swift-dev@swift.org</a>> wrote:<br class=""><br class="">Hi,<br class=""><br class="">I’d like to propose to deprecate the -Ounchecked swift optimization mode.<br class=""><br class="">The -Ounchecked mode actually contradicts one of the main goals of swift: to be a safe language.<br class="">In the past we didn’t see lot of significant performance differences compared to -O (there were some improvements but also some regressions).<br class="">Also, we want to reduce the effort of maintaining too many different optimization modes, especially because we recently added -Osize.<br class=""><br class="">Deprecating would mean that we map -Ounchecked to -O.<br class=""><br class="">If you have any comments or concerns, please let me know<br class=""><br class="">Thanks,<br class="">Erik<br class=""><br class=""><br class=""><br class="">_______________________________________________<br class="">swift-dev mailing list<br class=""><a href="mailto:swift-dev@swift.org" class="">swift-dev@swift.org</a><br class="">https://lists.swift.org/mailman/listinfo/swift-dev<br class=""></blockquote></blockquote></blockquote><br style="font-family: Helvetica; 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