[patch 3/N] std::regex refactoring - _Executor DFS / BFS

[Jonathan Wakely]

On 28/04/14 15:02 -0400, Tim Shen wrote:
>If we want to change it to a runtime flag, it should be a class
>member. Otherwise we have to pass it as a function parameter all the
>time, and it may waste an instruction and one byte per recursive call.
>It surely make the code cleaner.

Data members are accessed through the 'this' pointer, which can
require an indirection and be harder to optimise than a function
parameter.

>Am I premature optimizing?

I don't know yet - we need to measure.

My concern is that making it a template parameter causes twice as much
code to be instantiated, which makes executables bigger and can cause
more I-cache misses.