Don't rely on dmd when making raw performance tests. On my machine (i3-2100, two cores):
dmd2 -O -release -inline 3.14159 took 368[ms] 3.14159 took 713[ms] Speedup 1.9375 -5.80829e+09 took 61[ms] -5.80829e+09 took 201[ms] Speedup 3.29508 ldc2 -O3 -release 3.14159 took 360[ms] 3.14159 took 718[ms] Speedup 1.99444 -5.80829e+09 took 0[ms] -5.80829e+09 took 0[ms] Speedup -nan ldc2 -O3 -release -vectorize -vectorize-loops 3.14159 took 193[ms] 3.14159 took 721[ms] Speedup 3.73575 -5.80829e+09 took 0[ms] -5.80829e+09 took 0[ms] Speedup -nan
