text: /* u_2.c:   Undefined behaviors on undefined constant expression.   */
  
  /* { dg-do preprocess } */
  
  /* u.2.1:   Undefined escape sequence.  */
  #if     '\x'    /* { dg-error "no following hex digits| Undefined escape sequence '\\\\x'\n\[^ \]* warning:" } */
  #endif
  
  /* u.2.2:   Illegal bit shift count.    */
  /* dg-warning, not dg-error to avoid a problem of GCC 4.3 testsuite */
  #if     1 << -1 /* { dg-warning "Illegal shift count" } */
  #endif
  #if     1 << 64 /* { dg-error "integer overflow | Illegal shift count" } */
  #endif
  
  