gcc-4.4.0/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-u16b.c

/* { dg-require-effective-target vect_int } */

#include <stdarg.h>
#include "tree-vect.h"

#define N 64

#define DOT2 43680

unsigned short X[N] __attribute__ ((__aligned__(16)));
unsigned short Y[N] __attribute__ ((__aligned__(16)));

/* short->int->int dot product. 
   Currently not detected as a dot-product pattern: the multiplication 
   promotes the ushorts to int, and then the product is promoted to unsigned 
   int for the addition.  Which results in an int->unsigned int cast, which 
   since no bits are modified in the cast should be trivially vectorizable.  */
__attribute__ ((noinline)) unsigned int
foo2(int len) {
  int i;
  unsigned int result = 0;

  for (i=0; i<len; i++) {
    result += (X[i] * Y[i]);
  }
  return result;
}


int main (void)
{
  unsigned int  dot2;
  int i;

  check_vect ();

  for (i=0; i<N; i++) {
    X[i] = i;
    Y[i] = 64-i;
  }

  dot2 = foo2 (N);
  if (dot2 != DOT2)
    abort ();

  return 0;
}

/* { dg-final { scan-tree-dump-times "vect_recog_dot_prod_pattern: detected" 1 "vect" { xfail *-*-* } } } */

/* Once the dot-product pattern is detected, we expect
   that loop to be vectorized on vect_udot_hi targets (targets that support 
   dot-product of unsigned shorts) and targets that support widening multiplication.  */
/* The induction loop in main is vectorized.  */
/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 2 "vect" { xfail *-*-* } } } */ 
/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target vect_pack_trunc } } } */ 

/* { dg-final { cleanup-tree-dump "vect" } } */