gcc/testsuite/gcc.dg/tree-ssa/loop-interchange-9.c

   1 /* { dg-do run } */
   2 /* { dg-options "-O2 -floop-interchange -fdump-tree-linterchange-details" } */
   3 /* { dg-skip-if "too big data segment" { avr-*-* visium-*-* } } */
   4
   5 #define M 256
   6 int a[M][M], b[M][M], c[M], d[M];
   7 void __attribute__((noinline))
   8 simple_reduc_1 (int n)
   9 {
  10   for (int j = 0; j < n; j++)
  11     {
  12       int sum = c[j];
  13       for (int i = 0; i < n; i++)
  14         sum = sum + a[i][j]*b[i][j];
  15
  16       c[j] = sum;
  17     }
  18 }
  19
  20 void __attribute__((noinline))
  21 simple_reduc_2 (int n)
  22 {
  23   for (int j = 0; j < n; j++)
  24     {
  25       int sum = d[j];
  26       for (int i = 0; i < n; i++)
  27         sum = sum + a[i][j]*b[i][j];
  28
  29       asm volatile ("" ::: "memory");
  30       d[j] = sum;
  31     }
  32 }
  33
  34 extern void abort ();
  35
  36 static void __attribute__((noinline))
  37 init (int i)
  38 {
  39   c[i] = 0;
  40   d[i] = 0;
  41   for (int j = 0; j < M; j++)
  42     {
  43       a[i][j] = i;
  44       b[i][j] = j;
  45     }
  46 }
  47
  48 int main (void)
  49 {
  50   for (int i = 0; i < M; ++i)
  51     init (i);
  52
  53   simple_reduc_1 (M);
  54   simple_reduc_2 (M);
  55
  56   for (int i = 0; i < M; ++i)
  57     if (c[i] != d[i])
  58       abort ();
  59
  60   return 0;
  61 }
  62
  63 /* { dg-final { scan-tree-dump-times "Loop_pair<outer:., inner:.> is interchanged" 1 "linterchange" } } */