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<blockquote style="position: relative; padding-left: 55px;"><section><a href="https://mastodon.social/users/vegard/statuses/113163591734712480">Vegard Nossum (vegard@mastodon.social)'s status on Thursday, 19-Sep-2024 19:20:21 JST</a><a href="https://mastodon.social/@vegard" title="vegard@mastodon.social"><img src="https://gnusocial.jp/avatar/25475-48-20230328130305.webp" width="48" height="48" alt="Vegard Nossum" style="position: absolute; left: 0; top: 0;">Vegard Nossum</a><div><a href="https://f.duriansoftware.com/@joe/113159010531092225" rel="in-reply-to">in reply to</a><ul><li></ul></div></section><article><p><a href="https://f.duriansoftware.com/@joe">@joe</a> This program detects optimization level: <a href="https://gcc.godbolt.org/z/G956WzrrE" rel="nofollow noreferrer">https://gcc.godbolt.org/z/G956WzrrE</a></p></article><footer><a rel="bookmark" href="https://gnusocial.jp/conversation/3691011#notice-7235421">In conversation</a><time datetime="2024-09-19T19:20:21+09:00" title="Thursday, 19-Sep-2024 19:20:21 JST">about 2 months ago</time> <span>from <span><a href="https://mastodon.social/@vegard/113163591734712480" rel="external" title="Sent from mastodon.social via ActivityPub">mastodon.social</a></span></span><a href="https://mastodon.social/@vegard/113163591734712480">permalink</a><h4>Attachments</h4><ol><li><article><header><div>Domain not in remote thumbnail source whitelist: raw.githubusercontent.com</div><h5><a href="https://gcc.godbolt.org/z/G956WzrrE">Compiler Explorer - C++</a></h5><div> from <span>Matt Godbolt</span></div></header><div>int x, y;#define def(name, attr) \
    __attribute__ ((noinline, noclone, attr)) \
    int name() \
    { \
    a: \
        for (int i = 0; i &lt; y; ++i) \
            x=&amp;x+!x!=&amp;x==x; \
    b: \
        return (uintptr_t) &amp;&amp;b - (uintptr_t) &amp;&amp;a; \
    }def(fn, )
def(fn0, optimize(0));
def(fn1, optimize(1));
def(fn2, optimize(2));
def(fn3, optimize(3));int O()
{
    int s = fn();
    if (s == fn0())
        return 0;
    if (s == fn1())
        return 1;
    if (s == fn2())
        return 2;
    if (s == fn3())
        return 3;    return -1;
}int main(int argc, char *argv[])
{
    printf("-O%d\n", O());
    return 0;
}</div><footer></footer></article></li></ol></footer></blockquote>

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Vegard Nossum (vegard@mastodon.social)'s status on Thursday, 19-Sep-2024 19:20:21 JSTVegard Nossum
in reply to
- Joe Groff
@joe This program detects optimization level: https://gcc.godbolt.org/z/G956WzrrE
In conversationabout 2 months ago from mastodon.socialpermalink
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1. Domain not in remote thumbnail source whitelist: raw.githubusercontent.com
  Compiler Explorer - C++
  from Matt Godbolt
  int x, y; #define def(name, attr) \ __attribute__ ((noinline, noclone, attr)) \ int name() \ { \ a: \ for (int i = 0; i < y; ++i) \ x=&x+!x!=&x==x; \ b: \ return (uintptr_t) &&b - (uintptr_t) &&a; \ } def(fn, ) def(fn0, optimize(0)); def(fn1, optimize(1)); def(fn2, optimize(2)); def(fn3, optimize(3)); int O() { int s = fn(); if (s == fn0()) return 0; if (s == fn1()) return 1; if (s == fn2()) return 2; if (s == fn3()) return 3; return -1; } int main(int argc, char *argv[]) { printf("-O%d\n", O()); return 0; }

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