[Bug c++/67153] integer optimizations 53% slower than std::bitset<>

[ncm at cantrip dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67153

ncm at cantrip dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |Linux amd64
      Known to work|                            |4.9.2
               Host|                            |Linux amd64
            Version|5.1.0                       |5.1.1
      Known to fail|                            |5.1.1
              Build|                            |Linux amd64

--- Comment #2 from ncm at cantrip dot org ---
The 4.9.2 release, "Debian 4.9.2-10", does not exhibit this bug.  When built 
with g++-4.9, the unsigned int version is slightly faster than the
std::bitset<> 
version.  The g++-5 release used was "Debian 5.1.1-9 20150602".

The Haswell host is running under a virtualbox VM, with /proc/cpuinfo
reporting stepping 3, microcode 0x19, and flags: fpu vme de pse tsc msr 
pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 
ht syscall nx rdtscp lm constant_tsc rep_good nopl pni ssse3 lahf_lm

The compiler used for the test on the Westmere M520, that appears not to 
exhibit the bug, was a snapshot "g++ (GCC) 6.0.0 20150504".