For a concrete system for programming in an "SPMD" manner, take a look at ISPC for CPUs:

• https://ispc.github.io/
• https://pharr.org/matt/blog/2018/04/30/ispc-all.html
• https://pharr.org/matt/papers/ispc_inpar_2012.pdf

Or CUDA and OpenCL for GPUs:

• https://devblogs.nvidia.com/even-easier-introduction-cuda/