amd64/178792: -march=native fails with clang on certain CPU's

[Bert Regeer]

>Number:         178792
>Category:       amd64
>Synopsis:       -march=native fails with clang on certain CPU's
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-amd64
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon May 20 16:30:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     Bert Regeer
>Release:        FreeBSD 9.1-RELEASE
>Organization:
Absio Corporation
>Environment:
FreeBSD TestVM.absio.local 9.1-RELEASE FreeBSD 9.1-RELEASE #0 r243825: Tue Dec  4 09:23:10 UTC 2012     root at farrell.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
When compiling with clang passing the flag "-march=native" causes clang to fail with the following error message:

touch test.c
clang -march=native test.c
error: unknown target CPU 'i686'

This is an issue when the Python has also been installed with clang as the compiler, as all of the python packages from pypi that require a c compiler will invoke clang with the -march=native and fail.

It is only on certain CPU's that I am able to replicate the issue, see the following output from dmesg:

FreeBSD 9.1-RELEASE #0 r243825: Tue Dec  4 09:23:10 UTC 2012
    root at farrell.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC amd64
CPU: Intel(R) Core(TM) i7-3615QM CPU @ 2.30GHz (2294.19-MHz K8-class CPU)
  Origin = "GenuineIntel"  Id = 0x306a9  Family = 6  Model = 3a  Stepping = 9
  Features=0xfa3fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,DTS,MMX,FXSR,SSE,SSE2,SS>
  Features2=0x9e982203<SSE3,PCLMULQDQ,SSSE3,CX16,SSE4.1,SSE4.2,POPCNT,AESNI,XSAVE,OSXSAVE,AVX,HV>
  AMD Features=0x28100800<SYSCALL,NX,RDTSCP,LM>
  AMD Features2=0x1<LAHF>
  TSC: P-state invariant
>How-To-Repeat:
touch test.c
clang -march=native test.c
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: