You're in a bit of a different domain - I've never really done all that much stuff with heavy number crunching (I've done a bit of work on random forest travers

You're in a bit of a different domain - I've never really done all that much stuff with heavy number crunching (I've done a bit of work on random forest traversal, but that's more about logic than about FP). And I have never worked with ISPC. I think number crunching workloads are typically quite suitable for GPGPU - I'm certainly not trying to "debunk GPGPU", just saying that there are a lot of integer/logic intensive workloads that involve rapid switching back and forth between control/GPR-based-logic sides and "SIMD tasks" (e.g. Hyperscan switching between NFA/DFA simulation and "acceleration", which was SIMD-based character skipping).