gcc/testsuite/gcc.dg/vect/fast-math-pr43074.c

/* { dg-do compile } */

float
pvslockprocess(float *fout, float *fin, int framesize)
{
  int i;
  float mag=0.0f, diff;
  for (i = 0; i < framesize; i += 2) {
      mag += fin[i];
      fout[i] = fin[i];
      fout[i+1] = fin[i+1];
  }
  return mag;
}