clang/test/CodeGen/builtin-constant-p.c

   1 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -disable-llvm-optzns -o - %s -O2 | FileCheck %s
   2 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -disable-llvm-optzns -o - %s -O0 | FileCheck %s
   3
   4 int a = 42;
   5
   6 /* --- Compound literals */
   7
   8 struct foo { int x, y; };
   9
  10 int y;
  11 struct foo f = (struct foo){ __builtin_constant_p(y), 42 };
  12
  13 struct foo test0(int expr) {
  14   // CHECK-LABEL: test0
  15   // CHECK: call i1 @llvm.is.constant.i32
  16   struct foo f = (struct foo){ __builtin_constant_p(expr), 42 };
  17   return f;
  18 }
  19
  20 /* --- Pointer types */
  21
  22 int test1(void) {
  23   // CHECK-LABEL: test1
  24   // CHECK: ret i32 0
  25   return __builtin_constant_p(&a - 13);
  26 }
  27
  28 /* --- Aggregate types */
  29
  30 int b[] = {1, 2, 3};
  31
  32 int test2(void) {
  33   // CHECK-LABEL: test2
  34   // CHECK: ret i32 0
  35   return __builtin_constant_p(b);
  36 }
  37
  38 const char test3_c[] = {1, 2, 3, 0};
  39
  40 int test3(void) {
  41   // CHECK-LABEL: test3
  42   // CHECK: ret i32 0
  43   return __builtin_constant_p(test3_c);
  44 }
  45
  46 inline char test4_i(const char *x) {
  47   return x[1];
  48 }
  49
  50 int test4(void) {
  51   // CHECK: define{{.*}} i32 @test4
  52   // CHECK: ret i32 0
  53   return __builtin_constant_p(test4_i(test3_c));
  54 }
  55
  56 /* --- Constant global variables */
  57
  58 const int c = 42;
  59
  60 int test5(void) {
  61   // CHECK-LABEL: test5
  62   // CHECK: ret i32 1
  63   return __builtin_constant_p(c);
  64 }
  65
  66 /* --- Array types */
  67
  68 int arr[] = { 1, 2, 3 };
  69 const int c_arr[] = { 1, 2, 3 };
  70
  71 int test6(void) {
  72   // CHECK-LABEL: test6
  73   // CHECK: call i1 @llvm.is.constant.i32
  74   return __builtin_constant_p(arr[2]);
  75 }
  76
  77 int test7(void) {
  78   // CHECK-LABEL: test7
  79   // CHECK: ret i32 1
  80   return __builtin_constant_p(c_arr[2]);
  81 }
  82
  83 int test8(void) {
  84   // CHECK-LABEL: test8
  85   // CHECK: ret i32 0
  86   return __builtin_constant_p(c_arr);
  87 }
  88
  89 /* --- Function pointers */
  90
  91 int test9(void) {
  92   // CHECK-LABEL: test9
  93   // CHECK: ret i32 0
  94   return __builtin_constant_p(&test9);
  95 }
  96
  97 int test10(void) {
  98   // CHECK-LABEL: test10
  99   // CHECK: ret i32 1
 100   return __builtin_constant_p(&test10 != 0);
 101 }
 102
 103 typedef unsigned long uintptr_t;
 104 #define assign(p, v) ({ \
 105   uintptr_t _r_a_p__v = (uintptr_t)(v);                           \
 106   if (__builtin_constant_p(v) && _r_a_p__v == (uintptr_t)0) {     \
 107     union {                                                       \
 108       uintptr_t __val;                                            \
 109       char __c[1];                                                \
 110     } __u = {                                                     \
 111       .__val = (uintptr_t)_r_a_p__v                               \
 112     };                                                            \
 113     *(volatile unsigned int*)&p = *(unsigned int*)(__u.__c);      \
 114     __u.__val;                                                    \
 115   }                                                               \
 116   _r_a_p__v;                                                      \
 117 })
 118
 119 typedef void fn_p(void);
 120 extern fn_p *dest_p;
 121
 122 static void src_fn(void) {
 123 }
 124
 125 void test11(void) {
 126   assign(dest_p, src_fn);
 127 }
 128
 129 extern int test12_v;
 130
 131 struct { const char *t; int a; } test12[] = {
 132     { "tag", __builtin_constant_p(test12_v) && !test12_v ? 1 : 0 }
 133 };
 134
 135 extern char test13_v;
 136 struct { int a; } test13 = { __builtin_constant_p(test13_v) };
 137
 138 extern unsigned long long test14_v;
 139
 140 void test14(void) {
 141   // CHECK-LABEL: test14
 142   // CHECK: call void asm sideeffect "", {{.*}}(i32 -1)
 143   __asm__ __volatile__("" :: "n"( (__builtin_constant_p(test14_v) || 0) ? 1 : -1));
 144 }
 145
 146 int test15_f(void);
 147 // CHECK-LABEL: define{{.*}} void @test15
 148 // CHECK-NOT: call {{.*}}test15_f
 149 void test15(void) {
 150   int a, b;
 151   (void)__builtin_constant_p((a = b, test15_f()));
 152 }