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

   1 /* { dg-do compile { target i?86-*-* x86_64-*-* } } */
   2 /* { dg-require-effective-target ilp32 } */
   3 /* { dg-options "-O2 -fprefetch-loop-arrays -march=athlon -msse2 -mfpmath=sse --param simultaneous-prefetches=100 -fdump-tree-aprefetch-details" } */
   4
   5 #define N 1000
   6 #define K 900
   7
   8 double a[N][N];
   9
  10 double test(void)
  11 {
  12   unsigned i, j;
  13   double sum = 0;
  14
  15   /* Here, we should use non-temporal prefetch instruction.  */
  16   for (i = 0; i < K; i++)
  17     for (j = 0; j < K; j++)
  18       sum += a[i][j];
  19
  20   /* Here, we should not use non-temporal prefetch instruction, since the
  21      value of a[i+10][j] is reused in L2 cache.  */
  22   for (i = 0; i < K; i++)
  23     for (j = 0; j < K; j++)
  24       sum += a[i][j] * a[i + 10][j];
  25
  26   /* Here, we should use non-temporal prefetch instruction, since the
  27      value of a[i+100][j] is too far to be reused in L2 cache.  */
  28   for (i = 0; i < K; i++)
  29     for (j = 0; j < K; j++)
  30       sum += a[i][j] * a[i + 100][j];
  31
  32   /* Here, temporal prefetches should be used, since the volume of the
  33      memory accesses is smaller than L2 cache.  */
  34   for (i = 0; i < 100; i++)
  35     for (j = 0; j < 100; j++)
  36       sum += a[i][j] * a[i + 100][j];
  37
  38   /* Temporal prefetches should be used here (even though the accesses to
  39      a[j][i] are independent, the same cache line is almost always hit
  40      every N iterations).  */
  41   for (i = 0; i < N; i++)
  42     for (j = 0; j < N; j++)
  43       sum += a[j][i];
  44
  45   return sum;
  46 }
  47
  48 /* { dg-final { scan-tree-dump-times "Issued prefetch" 5 "aprefetch" } } */
  49 /* { dg-final { scan-tree-dump-times "Issued nontemporal prefetch" 3 "aprefetch" } } */
  50
  51 /* { dg-final { scan-assembler-times "prefetcht" 5 } } */
  52 /* { dg-final { scan-assembler-times "prefetchnta" 3 } } */
  53
  54 /* { dg-final { cleanup-tree-dump "aprefetch" } } */