1  /* Test to verify that the temporary doesn't trigger a bogus -Warray-bounds
       2     warning.  Distilled from libat_exchange_large_inplace in libatomic/gexch.c.
       3     { dg-do compile }
       4     { dg-options "-O2 -Wall" }  */
       5  
       6  typedef typeof (sizeof 0) size_t;
       7  
       8  extern void *memcpy (void*, const void*, size_t);
       9  
      10  void libat_exchange_large_inplace (size_t n, void *mptr, void *vptr)
      11  {
      12    char temp[1024];
      13  
      14    size_t i = 0;
      15  
      16    for (i = 0; n >= 1024; i += 1024, n -= 1024)
      17      {
      18        memcpy (temp, mptr + i, 1024);
      19  
      20        /* The memcpy call below results in the following:
      21  	 unsigned long ivtmp.7;
      22  
      23  	 ivtmp.7_4 = (unsigned long) mptr_9(D);
      24  	 ...
      25  	 <bb 4>
      26  	 # ivtmp.7_22 = PHI <ivtmp.7_4(3), ivtmp.7_5(4)>
      27  	 ...
      28  	 _1 = (void *) ivtmp.7_22;
      29  	 ...
      30  	 memcpy (_1, _2, 1024);
      31  
      32  	 Treating _1 as a pointer results in the bogus:
      33  	   warning: 'memcpy' offset 0 is out of the bounds [0, 8] of object 'ivtmp.7' with type 'long unsigned int' [-Warray-bounds]
      34  	   memcpy (mptr + i, vptr + i, 1024);
      35  	   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      36        */
      37        memcpy (mptr + i, vptr + i, 1024);
      38  
      39        memcpy (vptr + i, temp, 1024);
      40      }
      41  }