2.9.1  Canonical Loop Form
  2.9.2  Worksharing-Loop Construct
   2.9.2.1  Determining the Schedule of a Worksharing-Loop
  2.9.3  SIMD Directives
   2.9.3.1  simd Construct
   2.9.3.2  Worksharing-Loop SIMD Construct
   2.9.3.3  declare simd Directive
  2.9.4  distribute Loop Constructs
   2.9.4.1  distribute Construct
   2.9.4.2  distribute simd Construct
   2.9.4.3  Distribute Parallel Worksharing-Loop Construct
   2.9.4.4  Distribute Parallel Worksharing-Loop SIMD Construct
  2.9.5  loop Construct
  2.9.6  scan Directive