VisualDSP++ has a great deal of pragmas to deal with aliasing and optimization
at the loop-level. They are quite handy and require less work than restrict
imho. Aliasing is especially annoying with loops.
// tell the optimizer there is no pointer aliasing in the whole loop
#pragma no_alias
// minimum and maximum loop count
#pragma loop_count(24, 48, 8)
// tell the optimizer this loop can be run in parallel
// implies no_alias
// (similar to #pragma omp parallel for)
#pragma vector_for
for (i=0;i<taps;i++)
acc += x[i]*y[i];
Of course array slices operations are a convenient way to prevent aliasing
problems but carrying the length information is an overhead and could prevent
loop-unrolling.
