gcc/testsuite/g++.dg/vect/pr70729-nest.cc

// { dg-do compile }
// { dg-additional-options "-ffast-math -fopenmp-simd" }
// { dg-additional-options "-msse2" { target x86_64-*-* i?86-*-* } }

inline void* my_alloc (__SIZE_TYPE__ bytes) {void *ptr; __builtin_posix_memalign (&ptr, bytes, 128); return 0; }
inline void my_free (void* memory) {__builtin_free (memory);}
float W[100];

template <typename T>
class Vec
{
  const int isize;
	T* data;

public:

  Vec (int n) : isize (n) {data = (T*)my_alloc (isize*sizeof (T));}
  ~Vec () {my_free(data);}

  Vec& operator = (const Vec& other)	
    {
      if (this != &other)
	__builtin_memcpy (data, other.data, isize*sizeof (T));
      return *this;
    }

  T& operator [] (int i) {return data[i];}
  const T& operator [] (int i) const {return data[i];}
  T& at (int i)  {return data[i];}
  const T& at (int i) const {return data[i];}

  operator T* ()  {return data;}
  int size () const {return isize;}
};

template <typename T>                                  
class Cl
{
public:

  Cl (int n, int m);
  const int N, M;
  Vec<T> v_x, v_y;
  Vec<int> v_i;
  Vec<float> v_z;
};

struct Ss
{
    const int S_n, S_m;
    Cl<float> v1;
    float* C1;
    float* C2;
    Ss (int n1, int n2): S_n(n1), S_m(n2), v1(n1, n2)
      {
	C1 = new float[n1 * 3];
	C2 = new float[n2 * 4]; 
      }

    ~Ss () { delete C1; delete C2;}
   void foo (int n);
};
void Ss::foo (int n)
{
  float w;
  for (int j = 0; j < n; j++)
    {
      w = W[j];
#pragma omp simd
      for (int i = 0; i < S_n; i++)
	{
	  float w1 = C2[S_n + i] * w;
	  v1.v_i[i] += (int)w1;
	  C1[S_n + i] += w1;
	}
    }
}
 
// { dg-final { scan-tree-dump "LOOP VECTORIZED" "vect" { xfail *-*-* } } }