Why does "git log -G<regex>" works with "regexp-ignore-case" but not with other regexp-related options?

Hi,

I wonder why "git log -G<regexp>" works with the "regexp-ignore-case" option but not with the other regexp-related options? Wouldn't it be useful to make the "G<regex>" option support the following options?

  * basic-regexp
  * extended-regexp
  * fixed-strings
  * perl-regexp

Similarly I think it is not very consistent that one cannot combine any of the above options with the "S<string>" but instead have yet another option called "pickaxe-regex" to toggle between "fixed-string" and "extended-regexp" semantics for the argument passed to option "S".

The description of the above options in the git-log(1) manpage of Git version 2.1 do not explicitly say that they do not support the "G<regex>" and "S<string>" option.

Wouldn't it be nice to have all of the above options collaborate with each other?