Hm the above was not PGO. I tried again with PGO and it is not so good:
Mean +- std dev: [nbody_main_pgo] 177 ms +- 4 ms -> [nbody_specialized_pgo] 190 ms +- 2 ms: 1.07x slower
Mean +- std dev: [pidigits_main_pgo] 208 ms +- 1 ms -> [pidigits_specialized_pgo] 210 ms +- 2 ms: 1.01x slower
Mean +- std dev: [chaos_main_pgo] 106 ms +- 1 ms -> [chaos_specialized_pgo] 110 ms +- 1 ms: 1.04x slower
Mean +- std dev: [spectral_norm_main_pgo] 169 ms +- 7 ms -> [spectral_norm_specialized_pgo] 167 ms +- 1 ms: 1.02x faster
Benchmark hidden because not significant (1): raytrace