I have some cases where the new update doesn't want to auto-vectorize for a correctly assessed vector speedup of 1.5x to 2.0x, so now
(avoiding array assignment synttax) is needed to retain performance.
Similar cases for previous 2017 builds in C have been requiring conditional compilation with
#if ! __MIC__
#pragma omp simd safelen(1)
because the compiler is too aggressive when compiling for AVX2, and the update didn't require a change in source code.
Cilk plus still makes the optimum decision about vectorization of CEAN for both KNC and AVX2.
For more complete information about compiler optimizations, see our Optimization Notice.