• Use the fast floating point model to enable more aggressive optimizations or the precise floating point model to disable optimizations that are not value-safe on fast transcendental functions.

  Windows* OS	Linux* OS
  /fp:fast	-fp-model fast
  /fp:precise /Qfast-transcendentals	-fp-model precise -fast-transcendentals

  CAUTION: This may reduce floating point accuracy.

• Use the precise floating point model and enforce vectorization of the source loop using a directive: #pragma omp simd

Example

gcc program.c -O2 -fopenmp -fp-model precise -fast-transcendentals

#pragma omp simd collapse(2)
for (i=0; i<N; i++)
...

gcc program.c -O2 -fopenmp -fp-model precise -fast-transcendentals

#pragma omp simd collapse(2)
for (i=0; i<N; i++)
{
    a[i] = b[i] * c[i];
    for (i=0; i<N; i++)
    {
        d[i] = e[i] * f[i];
    }
}