The loop directive is a descriptive construct which allows the compiler
flexibility in how it generates code for the directive's associated
loop(s). See OpenMP specification 5.2 [257:8-9].
Codegen added in this patch for the combined 'loop' directives are:
'target teams loop' -> 'target teams distribute parallel for' 'teams loop' -> 'teams distribute parallel for' 'target parallel loop' -> 'target parallel for' 'parallel loop' -> 'parallel for'