1/* 2 This test checks promotion of bitfields. Bitfields should be promoted 3 very much like chars and shorts: 4 5 Bitfields (signed or unsigned) should be promoted to signed int if their 6 value will fit in a signed int, otherwise to an unsigned int if their 7 value will fit in an unsigned int, otherwise we don't promote them (ANSI/ISO 8 does not specify the behavior of bitfields larger than an unsigned int). 9 10 We test the behavior by subtracting two from the promoted value: this will 11 result in a negitive value for signed types, a positive value for unsigned 12 types. This test (of course) assumes that the compiler is correctly 13 implementing signed and unsigned arithmetic. 14 */ 15 16struct X { 17 unsigned int u3:3; 18 signed long int s31:31; 19 signed long int s32:32; 20 unsigned long int u31:31; 21 unsigned long int u32:32; 22 unsigned long long ull3 :3; 23 unsigned long long ull35:35; 24 unsigned u15:15; 25}; 26 27struct X x; 28 29main () 30{ 31 if ((x.u3 - 2) >= 0) /* promoted value should be signed */ 32 abort (); 33 34 if ((x.s31 - 2) >= 0) /* promoted value should be signed */ 35 abort (); 36 37 if ((x.s32 - 2) >= 0) /* promoted value should be signed */ 38 abort (); 39 40 if ((x.u15 - 2) >= 0) /* promoted value should be signed */ 41 abort (); 42 43 /* Conditionalize check on whether integers are 4 bytes or larger, i.e. 44 larger than a 31 bit bitfield. */ 45 if (sizeof (int) >= 4) 46 { 47 if ((x.u31 - 2) >= 0) /* promoted value should be signed */ 48 abort (); 49 } 50 else 51 { 52 if ((x.u31 - 2) < 0) /* promoted value should be UNsigned */ 53 abort (); 54 } 55 56 if ((x.u32 - 2) < 0) /* promoted value should be UNsigned */ 57 abort (); 58 59 if ((x.ull3 - 2) >= 0) /* promoted value should be signed */ 60 abort (); 61 62 if ((x.ull35 - 2) < 0) /* promoted value should be UNsigned */ 63 abort (); 64 65 exit (0); 66} 67