Date: Sun, 21 Jun 2026 23:48:12 +0200 From: =?UTF-8?B?VMSzbA==?= Coosemans <tijl@FreeBSD.org> To: Konstantin Belousov <kib@freebsd.org> Cc: Faraz Vahedi <kfv@kfv.io>, Warner Losh <imp@freebsd.org>, alc@freebsd.org, src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: 9d87c1aac4a8 - main - libc: Add missing kill_dependency macro Message-ID: <20260621234812.08eb82dc@hal.tijl.coosemans.org> In-Reply-To: <aje5XhVicjw0up3Q@kib.kiev.ua> References: <6a35ddd4.24ba1.2ad9343d@gitrepo.freebsd.org> <ajZxmJoxyjjx0TSO@kib.kiev.ua> <9A21692F-0B53-4303-85A8-57784BFAF8DE@kfv.io> <33E8BFC4-EA46-41A7-B54F-1AADD3C19D9E@kfv.io> <ajakKWNfv2dwegqj@kib.kiev.ua> <F34A8CEE-E3C5-4942-9543-698693B8FE7A@kfv.io> <aje5XhVicjw0up3Q@kib.kiev.ua>
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On Sun, 21 Jun 2026 13:13:50 +0300 Konstantin Belousov wrote: > On Sat, Jun 20, 2026 at 11:50:50PM +0330, Faraz Vahedi wrote: >> Hey, >> >> I see. I dug further into related proposals and the reasons why no >> compiler today has implemented true data dependency tracking >> and that they all basically map and promote consume to acquire. >> The kill_dependency is also basically a no-op, and both compilers >> optimise them identically. I did a few tests on my AArch64 box and >> that's how I'm convinced, so I believe keeping the current form >> could be ideal as it fully conforms to the standard and we're assured >> that at least any conforming compiler would support it just fine and >> there's no extension or non-standard tweak in it. On the other hand, >> although adding a separate branch with the GCC style is possible, I >> don't think that'd add any value but visual complications. >> >> Either way, whether dependency tracking changes drastically or this >> very approach becomes obsolete, keeping our header as-is seems >> safe for now. > I am fine with it then. My concern was in subtle breakage of the > code compiled with gcc. I think the GCC definition just enforces that Y and kill_dependency(Y) are expressions so things like the following produce an error. if kill_dependency(foo);home | help
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