sdcc/support/regression/tests/gcc-torture-execute-bitfld-1.c

   1 /*
   2    bitfld-1-1.c from the execute part of the gcc torture tests.
   3  */
   4
   5 #include <testfwk.h>
   6
   7 #ifdef __SDCC
   8 #pragma std_c89
   9 #endif
  10
  11 /* Copyright 2002 Free Software Foundation, Inc.
  12
  13    Tests correct signedness of operations on bitfields; in particular
  14    that integer promotions are done correctly, including the case when
  15    casts are present.
  16
  17    The C front end was eliding the cast of an unsigned bitfield to
  18    unsigned as a no-op, when in fact it forces a conversion to a
  19    full-width unsigned int. (At the time of writing, the C++ front end
  20    has a different bug; it erroneously promotes the uncast unsigned
  21    bitfield to an unsigned int).
  22
  23    Source: Neil Booth, 25 Jan 2002, based on PR 3325 (and 3326, which
  24    is a different manifestation of the same bug).
  25 */
  26
  27 extern void abort ();
  28
  29 void
  30 testTortureExecute (void)
  31 {
  32   struct x { signed int i : 7; unsigned int u : 7; } bit;
  33
  34   unsigned int u;
  35   int i;
  36   unsigned int unsigned_result = -13U % 61;
  37   int signed_result = -13 % 61;
  38
  39   bit.u = 61, u = 61;
  40   bit.i = -13, i = -13;
  41
  42   if (i % u != unsigned_result)
  43     ASSERT (0);
  44   if (i % (unsigned int) u != unsigned_result)
  45     ASSERT (0);
  46
  47   /* Somewhat counter-intuitively, bit.u is promoted to an int, making
  48      the operands and result an int.  */
  49   if (i % bit.u != signed_result)
  50     ASSERT (0);;
  51
  52   if (bit.i % bit.u != signed_result)
  53     ASSERT (0);
  54
  55   /* But with a cast to unsigned int, the unsigned int is promoted to
  56      itself as a no-op, and the operands and result are unsigned.  */
  57   if (i % (unsigned int) bit.u != unsigned_result)
  58     ASSERT (0);
  59
  60   if (bit.i % (unsigned int) bit.u != unsigned_result)
  61     ASSERT (0);
  62
  63   return;
  64 }