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      1 // RUN: %clang_cc1 -fsyntax-only -verify -triple x86_64-apple-darwin %s
      2 
      3 // This file tests -Wconstant-conversion, a subcategory of -Wconversion
      4 // which is on by default.
      5 
      6 // rdar://problem/6792488
      7 void test_6792488(void) {
      8   int x = 0x3ff0000000000000U; // expected-warning {{implicit conversion from 'unsigned long' to 'int' changes value from 4607182418800017408 to 0}}
      9 }
     10 
     11 void test_7809123(void) {
     12   struct { int i5 : 5; } a;
     13 
     14   a.i5 = 36; // expected-warning {{implicit truncation from 'int' to bitfield changes value from 36 to 4}}
     15 }
     16 
     17 void test() {
     18   struct { int bit : 1; } a;
     19   a.bit = 1; // shouldn't warn
     20 }
     21 
     22 enum Test2 { K_zero, K_one };
     23 enum Test2 test2(enum Test2 *t) {
     24   *t = 20;
     25   return 10; // shouldn't warn
     26 }
     27 
     28 void test3() {
     29   struct A {
     30     unsigned int foo : 2;
     31     int bar : 2;
     32   };
     33 
     34   struct A a = { 0, 10 };            // expected-warning {{implicit truncation from 'int' to bitfield changes value from 10 to -2}}
     35   struct A b[] = { 0, 10, 0, 0 };    // expected-warning {{implicit truncation from 'int' to bitfield changes value from 10 to -2}}
     36   struct A c[] = {{10, 0}};          // expected-warning {{implicit truncation from 'int' to bitfield changes value from 10 to 2}}
     37   struct A d = (struct A) { 10, 0 }; // expected-warning {{implicit truncation from 'int' to bitfield changes value from 10 to 2}}
     38   struct A e = { .foo = 10 };        // expected-warning {{implicit truncation from 'int' to bitfield changes value from 10 to 2}}
     39 }
     40 
     41 void test4() {
     42   struct A {
     43     char c : 2;
     44   } a;
     45 
     46   a.c = 0x101; // expected-warning {{implicit truncation from 'int' to bitfield changes value from 257 to 1}}
     47 }
     48 
     49 void test5() {
     50   struct A {
     51     _Bool b : 1;
     52   } a;
     53 
     54   // Don't warn about this implicit conversion to bool, or at least
     55   // don't warn about it just because it's a bitfield.
     56   a.b = 100;
     57 }
     58 
     59 void test6() {
     60   // Test that unreachable code doesn't trigger the truncation warning.
     61   unsigned char x = 0 ? 65535 : 1; // no-warning
     62   unsigned char y = 1 ? 65535 : 1; // expected-warning {{changes value}}
     63 }
     64 
     65 void test7() {
     66 	struct {
     67 		unsigned int twoBits1:2;
     68 		unsigned int twoBits2:2;
     69 		unsigned int reserved:28;
     70 	} f;
     71 
     72 	f.twoBits1 = ~1; // expected-warning {{implicit truncation from 'int' to bitfield changes value from -2 to 2}}
     73 	f.twoBits2 = ~2; // expected-warning {{implicit truncation from 'int' to bitfield changes value from -3 to 1}}
     74 	f.twoBits1 &= ~1; // no-warning
     75 	f.twoBits2 &= ~2; // no-warning
     76 }
     77 
     78 void test8() {
     79   enum E { A, B, C };
     80   struct { enum E x : 1; } f;
     81   f.x = C; // expected-warning {{implicit truncation from 'int' to bitfield changes value from 2 to 0}}
     82 }
     83