gcc/testsuite/gcc.dg/tree-ssa/prefetch-6.c

   1 /* { dg-do compile { target { i?86-*-* x86_64-*-* } } } */
   2 /* { dg-options "-O2 -fprefetch-loop-arrays -march=amdfam10 --param simultaneous-prefetches=100 --param min-insn-to-prefetch-ratio=6 -fdump-tree-aprefetch-details" } */
   3
   4 #define N 1000
   5 #define K 900
   6
   7 double a[N][N];
   8
   9 double test(void)
  10 {
  11   unsigned i, j;
  12   double sum = 0;
  13
  14   /* Here, we should use non-temporal prefetch instruction.  */
  15   for (i = 0; i < K; i++)
  16     for (j = 0; j < K; j++)
  17       sum += a[i][j];
  18
  19   /* Here, we should not use non-temporal prefetch instruction, since the
  20      value of a[i+10][j] is reused in L2 cache.  */
  21   for (i = 0; i < K; i++)
  22     for (j = 0; j < K; j++)
  23       sum += a[i][j] * a[i + 10][j];
  24
  25   /* Here, we should use non-temporal prefetch instruction, since the
  26      value of a[i+100][j] is too far to be reused in L2 cache.  */
  27   for (i = 0; i < K; i++)
  28     for (j = 0; j < K; j++)
  29       sum += a[i][j] * a[i + 100][j];
  30
  31   /* Here, temporal prefetches should be used, since the volume of the
  32      memory accesses is smaller than L2 cache.  */
  33   for (i = 0; i < 100; i++)
  34     for (j = 0; j < 100; j++)
  35       sum += a[i][j] * a[i + 100][j];
  36
  37   /* Temporal prefetches should be used here (even though the accesses to
  38      a[j][i] are independent, the same cache line is almost always hit
  39      every N iterations).  */
  40   for (i = 0; i < N; i++)
  41     for (j = 0; j < N; j++)
  42       sum += a[j][i];
  43
  44   return sum;
  45 }
  46
  47 /* { dg-final { scan-tree-dump-times "Issued prefetch" 5 "aprefetch" } } */
  48 /* { dg-final { scan-tree-dump-times "Issued nontemporal prefetch" 3 "aprefetch" } } */