On Tue Nov 8 11, Roman Divacky wrote: > clang will use "core2" for family=6 and model=15 > > check llvm/lib/Support/Host.cpp > > what is the problem? The fact that our gcc from the middle-ages > does not recognize that?
actually a few months ago quite a lot of gcc commits happend to add newer optimisations (such as core2) to gcc and some commits aimed at modifying gcc, so it would make the best -march=native choice there is. what's the clang command (similar to gcc -march=native -E -v - </dev/null), one can use to check what actual optimisation clang turns "native" into? also there seem to be cross-compilation issues. when people are running i386 and want to cross-compile for amd64 and put CPUTYPE=core2 (or any other amd64 cpu) into their make.conf, this gets downgraded by bsd.cpu.mk to prescott. see http://www.freebsd.org/cgi/query-pr.cgi?pr=conf/84800 and http://www.mail-archive.com/freebsd-hackers@freebsd.org/msg161451.html cheers. alex > > On Tue, Nov 08, 2011 at 09:04:20PM +0000, Alexander Best wrote: > > On Tue Nov 8 11, Roman Divacky wrote: > > > On Tue, Nov 08, 2011 at 08:55:39AM +0100, Dimitry Andric wrote: > > > > On 2011-11-08 01:25, Alexander Best wrote: > > > > > i've seen dozens of issues, where people set CPUTYPE=native. although > > > > > this > > > > > works in a lot of cases, it doesn't in others. why don't we simply add > > > > > something like > > > > > > > > > > . if ${CPUTYPE} == "native" > > > > > . error "bla" > > > > > . endif > > > > > > > > > > in share/mk/bsd.cpu.mk for now? or at least for the archs, where > > > > > "native" is > > > > > known to cause problems. > > > > > > > > What does this solve? Don't you think it is better to try to fix the > > > > actual problems? Some people like being able to optimize for their > > > > > > Yes, we definitely should aim for fixing the problems instead of working > > > around them. > > > > > > This way both clang and freebsd benefits. > > > > for me -march=native reports: > > > > otaku% gcc -march=native -E -v - </dev/null > > Using built-in specs. > > Target: amd64-undermydesk-freebsd > > Configured with: FreeBSD/amd64 system compiler > > Thread model: posix > > gcc version 4.2.2 20070831 prerelease [FreeBSD] > > /usr/libexec/cc1 -E -quiet -v -D_LONGLONG - -march=nocona -mtune=generic > > #include "..." search starts here: > > #include <...> search starts here: > > /usr/include/gcc/4.2 > > /usr/include > > End of search list. > > # 1 "<stdin>" > > # 1 "<built-in>" > > # 1 "<command-line>" > > # 1 "<stdin>" > > > > where instead of nocona, core2 would have been the better choice: > > > > [1.000000] CPU: Intel(R) Pentium(R) Dual CPU E2160 @ 1.80GHz > > (1800.00-MHz K8-class CPU) > > [1.000000] Origin = "GenuineIntel" Id = 0x6fd Family = 6 Model = f > > Stepping = 13 > > [1.000000] > > Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> > > [1.000000] > > Features2=0xe39d<SSE3,DTES64,MON,DS_CPL,EST,TM2,SSSE3,CX16,xTPR,PDCM> > > [1.000000] AMD Features=0x20100800<SYSCALL,NX,LM> > > [1.000000] AMD Features2=0x1<LAHF> > > [1.000000] TSC: P-state invariant, performance statistics > > > > cheers. > > alex > > > > > > > > roman _______________________________________________ freebsd-toolchain@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-toolchain To unsubscribe, send any mail to "freebsd-toolchain-unsubscr...@freebsd.org"
