http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55600
--- Comment #2 from Ondrej Bilka <neleai at seznam dot cz> 2012-12-26 22:03:59 UTC --- Yes when 128 is replaced by smaller constant. Attached patch gives on my i5 following: size 32 vector real 0m0.224s user 0m0.220s sys 0m0.000s unroll real 0m0.155s user 0m0.148s sys 0m0.004s size 64 vector real 0m0.398s user 0m0.396s sys 0m0.000s unroll real 0m0.380s user 0m0.376s sys 0m0.000s size 128 vector real 0m0.703s user 0m0.700s sys 0m0.000s unroll real 0m0.817s user 0m0.812s sys 0m0.000s