[Patch] Refactor regex executors

[Tim Shen]

This patch optimizes BFS executor by removing quantifier tracking, but
precisely control the assignment order of the variable recording the
optimal solution.

Remove the string_dispatch_01.cc testcase, because there's no
_DFSExecutor or _BFSExecutor to detect(using dynamic_cast), and
actually the dispatching seems simple enough not to deserve a
testcase.

Booted and tested under -m32 and -m64.

Thanks!


-- 
Regards,
Tim Shen
-------------- next part --------------
A non-text attachment was scrubbed...
Name: a.patch
Type: text/x-patch
Size: 44828 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/libstdc++/attachments/20131025/32456734/attachment.bin>