gcc/testsuite/gcc.dg/tree-ssa/loop-interchange-6.c

   1 /* { dg-do run } */
   2 /* { dg-options "-O2 -floop-interchange -fdump-tree-linterchange-details" } */
   3
   4 #define M 256
   5 int a[M][M], b[M][M], c[M][M], d[M][M];
   6 void __attribute__((noinline))
   7 matrix_mul_1 (int n)
   8 {
   9     for (int j = 0; j < n; j++)
  10       for (int k = 0; k < n; k++)
  11   for (int i = 0; i < n; i++)
  12         c[i][j] = c[i][j] + a[i][k]*b[k][j];
  13 }
  14
  15 void __attribute__((noinline))
  16 matrix_mul_2 (int n)
  17 {
  18   for (int i = 0; i < n; i++)
  19     {
  20       for (int j = 0; j < n; j++)
  21         {
  22           for (int k = 0; k < n; k++)
  23             d[i][j] = d[i][j] + a[i][k]*b[k][j];
  24
  25           asm volatile ("" ::: "memory");
  26         }
  27       asm volatile ("" ::: "memory");
  28     }
  29 }
  30
  31 extern void abort ();
  32
  33 static void __attribute__((noinline))
  34 init (int i)
  35 {
  36   for (int j = 0; j < M; j++)
  37     {
  38       a[i][j] = i;
  39       b[i][j] = j;
  40       c[i][j] = 0;
  41       d[i][j] = 0;
  42     }
  43 }
  44
  45 static int __attribute__((noinline))
  46 check (int i)
  47 {
  48   for (int j = 0; j < M; j++)
  49     if (c[i][j] != d[i][j])
  50       return 0;
  51
  52   return 1;
  53 }
  54
  55 int main (void)
  56 {
  57   for (int i = 0; i < M; ++i)
  58     init (i);
  59
  60   matrix_mul_1 (M);
  61   matrix_mul_2 (M);
  62
  63   for (int i = 0; i < M; ++i)
  64     if (!check (i))
  65       abort ();
  66
  67   return 0;
  68 }
  69
  70 /* { dg-final { scan-tree-dump-times "Loop_pair<outer:., inner:.> is interchanged" 2 "linterchange" } } */