[Bug tree-optimization/56407] [4.7 Regression] Optimizations (-O2 -O3) make comparison of arrays of ints to fail

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56407



--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> 2013-04-03 
10:22:53 UTC ---

Testcase, also fails at -O2:



/* { dg-do run } */



extern void abort(void);

extern int rand(void);



static void copy(int *r,int *a,int na)

{

  int i;

  for( i = 0 ; i < na ; i++ )

    r[i] = a[i];

}



static void foo(int *a,int na)

{

  int i;

  for( i = 0 ; i < na ; i++ )

    a[i] = rand();

}



static int cmp(int *a,int *b,int n)

{

  int i;

  for( i = 0 ; i < n ; i++ )

    if ( a[i] != b[i] )

      return -1;

  return 0;

}



void __attribute__((noinline,noclone))

test(int sz,int comm)

{

  int j,n;

  int v[64],w[64];

  for( j = 1 ; j <= sz ; j++ )

    {

      n = (2 * j - 1) * (2 * j - 1);

      foo(w,n);

      copy(v,w,n);

      if ( comm )

        if ( cmp(v,w,n) ) abort ();

    }

}



int main()

{

  test(2,1);

  return 0;

}