Starting with Volta, Nvidia GPUs have forward progress guarantee, preventing lockups when there’s thread divergence.
That doesn’t improve the performance of a well behaved and well written compute shader. But avoiding hard hangs IMO deserves the label “improved thread divergence.”
CPUs have extremely flexible pipelines: Intel's pipeline 0 and 1 basically can do anything, pipeline 5 can do most stuff but is missing division IIRC (and a few other things). Load/store are done on some other pipelines, etc. etc.
Apple's and AMD's CPU pipelines are more symmetrical and uniform.
NVidia GPUs are the only superscalar ones I can think of, aside from AMD GPU's scalar vs vector split (which isn't really the "superscalar" operation I'm trying to describe).