Issue 4: possible speedup by using an SIMD popcount
Status:  New
Owner: ----
Reported by dbremner@gmail.com, Oct 16, 2012
The gcc builtin uses a lookup table but it is possible to do better.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36041 - existing gcc bug for improving the builtin popcount. 

https://groups.google.com/group/comp.arch/msg/ba28c5dbd47a3bba?dmode=source&output=gplain&noredirect&pli=1 - this post by Terje Mathisen describes the technique
Oct 18, 2012
Project Member #1 p...@google.com
Thank you for hints. 
Doesn't look like high priority stuff, but feel free to provide the patch. 
Otherwise we will probably wait for the fix in gcc. 
Labels: -Type-Defect -Priority-Medium Type-Enhancement Priority-Low