[Bug libstdc++/50160] vector<bool> comparison very slow (no overload)

[joseph at codesourcery dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50160

--- Comment #26 from joseph at codesourcery dot com <joseph at codesourcery dot com> 2011-08-31 15:23:56 UTC ---
Various processors have an instruction to reverse the bit order in a word 
(ARMv6T2 and later have RBIT, for example, and C6X has BITR on C64X and 
above).  I think a generic built-in function (variants for different type 
sizes) with associated generic RTL representation and lowering for 
processors without such an instruction makes sense.