Date: Mon, 09 Feb 2015 16:55:52 -0500 From: Jung-uk Kim <jkim@FreeBSD.org> To: John Baldwin <jhb@freebsd.org>, src-committers@freebsd.org Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org Subject: Re: svn commit: r278474 - head/sys/sys Message-ID: <54D92CE8.1030803@FreeBSD.org> In-Reply-To: <1698688.fEq0HxqPxg@ralph.baldwin.cx> References: <201502092103.t19L3OAn013792@svn.freebsd.org> <1698688.fEq0HxqPxg@ralph.baldwin.cx>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 02/09/2015 16:08, John Baldwin wrote: > On Monday, February 09, 2015 09:03:24 PM John Baldwin wrote: >> Author: jhb Date: Mon Feb 9 21:03:23 2015 New Revision: 278474 >> URL: https://svnweb.freebsd.org/changeset/base/278474 >> >> Log: Use __builtin_popcnt() to implement a BIT_COUNT() operation >> for bitsets and use this to implement CPU_COUNT() to count the >> number of CPUs in a cpuset. >> >> MFC after: 2 weeks > > Yes, __builtin_popcnt() works with GCC 4.2. It should also allow > the compiler to DTRT in userland uses of this if -msse4.2 is > enabled. Back in 2012, when I submitted a similar patch, bde noted __builtin_popcount*() cannot be used with GCC 4.2 for *kernel* because it emits a library call. http://docs.freebsd.org/cgi/mid.cgi?20121116171923.L1135 FYI... Jung-uk Kim -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJU2SzhAAoJEHyflib82/FGzgoH/2mfCZTX6J84MYpfuJV5dnLQ 97Itozifc8qBNDCOIQ1PZNgxPed9U8Ma0o3Rntfl5X2VeAIc/c5JJhvQITUdhnn7 fyW5FcpvJGpHLcUWlTMT5CrZgmDswi6h1jIsbD6AKoIVNGau5kPhpn4LF7f19YU0 0Vm8L96gGrxjJb3SWdRC4znP1ezTCw3rUEyk2oPZBn69zoat1vBcV7WtathStcBg noIEydo6C5e4EC5SKbTi29aNd1KGafRIukkC8+jnZNCc8nYEVsUEX5SarKYmmpec NTSLfboTJ5YXZGsvIgGzld0Z/Hn54v8O0hhG1QO4kWh3wN40NVgNL0vkeiveqwE= =WDqA -----END PGP SIGNATURE-----
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