1  /* PR middle-end/63272 - GCC should warn when using pointer to dead scoped
       2     variable within the same function
       3     Exercise conditional uses dangling pointers with optimization.
       4     { dg-do compile }
       5     { dg-options "-O2 -Wall -Wno-maybe-uninitialized" } */
       6  
       7  typedef __INTPTR_TYPE__ intptr_t;
       8  typedef __SIZE_TYPE__   size_t;
       9  
      10  #if __cplusplus
      11  #  define EXTERN_C extern "C"
      12  #else
      13  #  define EXTERN_C extern
      14  #endif
      15  
      16  EXTERN_C void* memcpy (void*, const void*, size_t);
      17  
      18  void sink (const void*, ...);
      19  
      20  char* nowarn_conditional (char *s)
      21  {
      22    // Reduced from Glibc's tmpnam.c.
      23    extern char a[5];
      24    char b[5];
      25    char *p = s ? s : b;
      26  
      27    sink (p);
      28  
      29    if (s == 0)
      30      return a;
      31  
      32    return s;
      33  }
      34  
      35  
      36  char* nowarn_conditional_memcpy (char *s)
      37  {
      38    // Reduced from Glibc's tmpnam.c.
      39    extern char a[5];
      40    char b[5];
      41    char *p = s ? s : b;
      42  
      43    sink (p);
      44  
      45    if (s == 0)
      46      return (char*)memcpy (a, p, 5);
      47  
      48    return s;
      49  }
      50  
      51  
      52  int warn_conditional_block (int i)
      53  {
      54    int *p;
      55    if (i)
      56    {
      57      int a[] = { 1, 2, 3 };
      58      p = &a[i];
      59    }
      60    else
      61      p = &i;
      62  
      63    return *p;        // { dg-warning "dangling pointer \('p' \)to 'a' may be used" }
      64  }