Clang 3.6 only advertises SSE2

[Jeffrey Walton]

I'm working on a 5th generation Core i5 (see /proc/cpuinfo below). The CPU offers SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AES, RDRAND, RDSEED, etc.

After installing Clang 3.6, the compiler claims SSE2 is all that is available:

$ clang++ -march=native -dM -E - < /dev/null | egrep -i '(sse|aes|rdrnd|rdseed|avx|bmi)' | sort
#define __SSE__ 1
#define __SSE2__ 1
#define __SSE2_MATH__ 1
#define __SSE_MATH__ 1

$ g++ -march=native -dM -E - < /dev/null | egrep -i '(sse|aes|rdrnd|rdseed|avx|bmi)' | sort
#define __AES__ 1
#define __AVX__ 1
#define __AVX2__ 1
#define __BMI__ 1
#define __BMI2__ 1
#define __core_avx2 1
#define __core_avx2__ 1
#define __RDRND__ 1
#define __RDSEED__ 1
#define __SSE__ 1
#define __SSE2__ 1
#define __SSE2_MATH__ 1
#define __SSE3__ 1
#define __SSE4_1__ 1
#define __SSE4_2__ 1
#define __SSE_MATH__ 1
#define __SSSE3__ 1

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This is nearly the same report as "Clang 3.4 only advertises SSE2", http://bugs.launchpad.net/ubuntu/+source/llvm-toolchain-3.4/+bug/1616723; and "Clang 3.5 only advertises SSE2", https://bugs.launchpad.net/ubuntu/+source/llvm-toolchain-3.4/+bug/1616729.

A separate report was provided in case they get worked separately.

========================================

$ cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 61
model name : Intel(R) Core(TM) i5-5300U CPU @ 2.30GHz
stepping : 4
microcode : 0x16
cpu MHz : 800.058
cache size : 3072 KB
physical id : 0
siblings : 4
core id : 0
cpu cores : 2
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 20
wp : yes
flags : 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 ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch ida arat epb pln pts dtherm tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm rdseed adx smap xsaveopt
...

========================================

$ uname -a
Linux qotom 3.19.0-66-generic #74~14.04.1-Ubuntu SMP Tue Jul 19 19:56:11 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.5 LTS
Release: 14.04
Codename: trusty

$ clang -v
Ubuntu clang version 3.6.0-2ubuntu1~trusty1 (tags/RELEASE_360/final) (based on LLVM 3.6.0)
Target: x86_64-pc-linux-gnu
Thread model: posix

$ dpkg -l clang-3.6
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-==============-============-============-=================================
ii clang-3.6 1:3.6-2ubunt amd64 C, C++ and Objective-C compiler (