gcc/testsuite/gcc.dg/vect/slp-reduc-11.c

   1 /* { dg-do compile } */
   2 /* { dg-require-effective-target vect_double } */
   3
   4 double dotprod(const double *a, const double *b, unsigned long long n)
   5 {
   6   double d1 = 0.0;
   7   double d2 = 0.0;
   8
   9   for (unsigned long long i = 0; i < n; i += 2) {
  10     d1 += a[i] * b[i];
  11     d2 += a[i + 1] * b[i + 1];
  12   }
  13
  14   return (d1 + d2);
  15 }
  16
  17 /* We should use a SLP reduction even without -ffast-math by using a
  18    VF of one.  */
  19 /* { dg-final { scan-tree-dump "vectorizing stmts using SLP" "vect" { xfail vect_variable_length } } } */
  20 /* { dg-final { scan-tree-dump "vectorized 1 loops" "vect" } } */