issue with clang and CPUTYPE native
Alexander Best
arundel at freebsd.org
Thu Dec 30 18:40:48 UTC 2010
On Thu Dec 30 10, Roman Divacky wrote:
> On Thu, Dec 30, 2010 at 12:20:33AM +0000, Alexander Best wrote:
> > On Tue Dec 28 10, Roman Divacky wrote:
> > > -march=native in clang works by detecting CPU name
> > > and passing it (if found) to llvm. if the CPU is not
> > > detected nothing is passed.
> > >
> > > nocona is supported
> > >
> > > ie. leaving the CPUNAME empty or specifying it to "nocona" should
> > > be equivalent to setting it to "native".
> > >
> > >
> > > can you apply this patch:
> > >
> > > Index: Driver/Tools.cpp
> > > ===================================================================
> > > --- Driver/Tools.cpp (revision 122591)
> > > +++ Driver/Tools.cpp (working copy)
> > > @@ -684,6 +684,7 @@
> > > // FIXME: We should also incorporate the detected target features for use
> > > // with -native.
> > > std::string CPU = llvm::sys::getHostCPUName();
> > > + llvm::outs() << "detected CPU = " << CPU << "\n";
> > > if (!CPU.empty())
> > > CPUName = Args.MakeArgString(CPU);
> > > } else
> >
> > thanks a lot for the patch. i've applied it, but am not sure how to only
> > compile clang. 'make' in usr.bin/clang fails. do i have to run target
> > buildworld or is there a way to only build clang?
>
> I would guess that cd lib/clang && make && cd ../../usr.bin/clang && make
> should work, if not - full buildworld is necessary I guess
thanks. that worked. this is what clang detects as my cpu:
-march=native
this the dmesg output:
CPU: Intel(R) Pentium(R) Dual CPU E2160 @ 1.80GHz (2394.05-MHz K8-class CPU)
Origin = "GenuineIntel" Id = 0x6fd Family = 6 Model = f Stepping = 13
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>
Features2=0xe39d<SSE3,DTES64,MON,DS_CPL,EST,TM2,SSSE3,CX16,xTPR,PDCM>
AMD Features=0x20100800<SYSCALL,NX,LM>
AMD Features2=0x1<LAHF>
TSC: P-state invariant
cheers.
alex
--
a13x
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