История изменений

$ clang --version
clang version 3.7.1 (tags/RELEASE_371/final)
Target: x86_64-unknown-linux-gnu
Thread model: posix

$ gcc --version
gcc (GCC) 5.3.0
Copyright (C) 2015 Free Software Foundation, Inc.
Это свободно распространяемое программное обеспечение. Условия копирования
приведены в исходных текстах. Без гарантии каких-либо качеств, включая 
коммерческую ценность и применимость для каких-либо целей.

$ for i in {0..10}; do time g++ -std=gnu++1y boost_variant.cpp -o boost_variant -O0 >/dev/null; done

real 1.341      user 0.838      sys 0.262       pcpu 82.04
real 0.899      user 0.824      sys 0.072       pcpu 99.63
real 0.901      user 0.821      sys 0.077       pcpu 99.71
real 0.902      user 0.833      sys 0.067       pcpu 99.75
real 0.892      user 0.813      sys 0.076       pcpu 99.62
real 0.912      user 0.827      sys 0.082       pcpu 99.72
real 0.925      user 0.847      sys 0.076       pcpu 99.75
real 0.908      user 0.824      sys 0.083       pcpu 99.84
real 0.899      user 0.834      sys 0.061       pcpu 99.57
real 0.898      user 0.826      sys 0.068       pcpu 99.59
real 0.911      user 0.833      sys 0.075       pcpu 99.65

$ for i in {0..10}; do time clang++ -std=gnu++1y boost_variant.cpp -o boost_variant -O0 >/dev/null; done                                                                                                 
real 1.010      user 0.611      sys 0.248       pcpu 85.01
real 0.646      user 0.611      sys 0.033       pcpu 99.68
real 0.650      user 0.618      sys 0.031       pcpu 99.79
real 0.666      user 0.630      sys 0.033       pcpu 99.61
real 0.640      user 0.598      sys 0.040       pcpu 99.76
real 0.651      user 0.613      sys 0.036       pcpu 99.72
real 0.642      user 0.607      sys 0.034       pcpu 99.83
real 0.651      user 0.614      sys 0.035       pcpu 99.76
real 0.646      user 0.618      sys 0.025       pcpu 99.60
real 0.651      user 0.610      sys 0.040       pcpu 99.90
real 0.657      user 0.621      sys 0.032       pcpu 99.45

$ for i in {0..10}; do time g++ -std=gnu++1y boost_variant.cpp -o boost_variant -O0 >/dev/null; done

real 1.341      user 0.838      sys 0.262       pcpu 82.04
real 0.899      user 0.824      sys 0.072       pcpu 99.63
real 0.901      user 0.821      sys 0.077       pcpu 99.71
real 0.902      user 0.833      sys 0.067       pcpu 99.75
real 0.892      user 0.813      sys 0.076       pcpu 99.62
real 0.912      user 0.827      sys 0.082       pcpu 99.72
real 0.925      user 0.847      sys 0.076       pcpu 99.75
real 0.908      user 0.824      sys 0.083       pcpu 99.84
real 0.899      user 0.834      sys 0.061       pcpu 99.57
real 0.898      user 0.826      sys 0.068       pcpu 99.59
real 0.911      user 0.833      sys 0.075       pcpu 99.65

$ for i in {0..10}; do time clang++ -std=gnu++1y boost_variant.cpp -o boost_variant -O0 >/dev/null; done                                                                                                 
real 1.010      user 0.611      sys 0.248       pcpu 85.01
real 0.646      user 0.611      sys 0.033       pcpu 99.68
real 0.650      user 0.618      sys 0.031       pcpu 99.79
real 0.666      user 0.630      sys 0.033       pcpu 99.61
real 0.640      user 0.598      sys 0.040       pcpu 99.76
real 0.651      user 0.613      sys 0.036       pcpu 99.72
real 0.642      user 0.607      sys 0.034       pcpu 99.83
real 0.651      user 0.614      sys 0.035       pcpu 99.76
real 0.646      user 0.618      sys 0.025       pcpu 99.60
real 0.651      user 0.610      sys 0.040       pcpu 99.90
real 0.657      user 0.621      sys 0.032       pcpu 99.45