This is actually something the ISO C++ committee is looking at. See https://isocpp.org/std/the-committee https://isocpp.org/std/the-committee - SG12 An exampl

This is actually something the ISO C++ committee is looking at. See https://isocpp.org/std/the-committee https://isocpp.org/std/the-committee - SG12 An example of this is P0145R0 which specifies the previously unspecified order of evaluation. See https://isocpp.org/blog/2015/11/kona-standards-meeting-trip-report https://isocpp.org/blog/2015/11/kona-standards-meeting-trip-... Apparently, the performance difference is expected to be zero on currently popular architectures and around 1% on older architectures.