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.
