Atomic ARC

[sky_khan]

Hint: mm: arc; threads: on; opt: speed; options: -d:release 176527 lines; 
6.574s; 609.012MiB peakmem;

Hint: mm: atomicArc; threads: on; opt: speed; options: -d:release 176527 lines; 
7.462s; 609.34MiB peakmem;

i7-6700K ddr4 2666