Nesting restriction

[jakub]

2.16 disallows any OpenMP constructs in simd region. For most of the constructs it is logical, but I wonder if/why that includes also the #pragma omp declare simd construct.
While it is a construct, not a directive, it doesn't result in any code generated at that point, and especially in #pragma omp simd might be useful.
Consider

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int a[1024], b[1024];
void foo ()
{
  int i;
#pragma omp simd safelen (8)
  for (i = 0; i < 1024; i++)
    {
    #pragma omp declare simd simdlen (8) linear (b)
      extern int bar (int, int b);
      a[i] = bar (a[i], i) + b[i];
    }

One would be forced to prototype bar before the simd loop or at global scope etc. instead, while that is what will usually happen anyway, any reason to enforce it?

[jakub]

Similarly, in #pragma omp declare simd description (2.8.2) the restrictions say that the execution of the body can't result in execution of an OpenMP construct. Does this preclude

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#pragma omp declare simd
int foo (int x, int y)
{
  #pragma omp declare simd
  extern int bar (int x, int y);
  return x + bar (x, y) + y;
}

? Given that #pragma omp declare simd is just a declarative construct, there is nothing to execute. Unless the elemental function itself is considered an OpenMP construct.