Diagnostic 15535: xxxx was not vectorized: loop contains switch statement. Consider using if-else statement

Cause:

This vectorization diagnostic is emitted starting from Intel(R) C++ Compiler 15.0. There is a limit to compiler's automatic transformation due to the cost modeling. If vectorization is essential, consider using explicitly using if-else or use explicit vector programming such as SIMD directive.

Examples:

void foo(float *A, int *B, int N){
  int i;
  for (i=0;i<N;i++){
    switch(B[i]){
    case 1: A[i]++;
    case 2: A[i]+=2;
    case 3: A[i]+=3;
    case 4: A[i]+=4;
    case 5: A[i]+=5;
    }
  }
}