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<p class="MsoNormal">FYI David is referring to PGSO (profile-guided size optimization) as it exists directly under that name, see:
<a href="https://reviews.llvm.org/D67120">https://reviews.llvm.org/D67120</a>. And yeah using PGSO is selecting optsize while this change is selecting optnone.<o:p></o:p></p>
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<p class="MsoNormal">On 9/9/20, 10:58 AM, "llvm-dev on behalf of Tobias Hieta via llvm-dev" <<a href="mailto:llvm-dev-bounces@lists.llvm.org">llvm-dev-bounces@lists.llvm.org</a> on behalf of
<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal">Would it make sense to have a flag to select optnone or optsize? We would probably also do the tradeoff for a smaller binary. <o:p></o:p></p>
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<p class="MsoNormal">On Wed, Sep 9, 2020, 19:28 Renato Golin <<a href="mailto:rengolin@gmail.com">rengolin@gmail.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal">On Wed, 9 Sep 2020 at 18:15, Min-Yih Hsu via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal">David mentioned in D87337 that LLVM has used similar techniques on code size (not sure what he was referencing, my guess will be something related to hot-cold code splitting).<o:p></o:p></p>
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<p class="MsoNormal">IIUC, it's just using optsize instead of optnone. The idea is that, if the code really doesn't run often/at all, then the performance impact of reducing the size is negligible, but the size impact is considerable.<o:p></o:p></p>
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<p class="MsoNormal">I'd wager that optsize could even be faster than optnone, as it would delete a lot of useless code... but not noticeable, as it wouldn't run much.<o:p></o:p></p>
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<p class="MsoNormal">This is an idea that we (Verona Language) are interested in, too.<o:p></o:p></p>
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