clang/test/CodeGenCXX/builtins.cpp

// RUN: %clang_cc1 -triple=x86_64-linux-gnu -emit-llvm -o - %s | FileCheck %s

// Builtins inside a namespace inside an extern "C" must be considered builtins.
extern "C" {
namespace X {
double __builtin_fabs(double);
float __builtin_fabsf(float) noexcept;
} // namespace X
}

int o = X::__builtin_fabs(-2.0);
// CHECK: @o ={{.*}} global i32 2, align 4

long p = X::__builtin_fabsf(-3.0f);
// CHECK: @p ={{.*}} global i64 3, align 8

// PR8839
extern "C" char memmove();

int main() {
  // CHECK: call {{signext i8|i8}} @memmove()
  return memmove();
}

struct S;
// CHECK: define {{.*}} @_Z9addressofbR1SS0_(
S *addressof(bool b, S &s, S &t) {
  // CHECK: %[[LVALUE:.*]] = phi
  // CHECK: ret {{.*}}* %[[LVALUE]]
  return __builtin_addressof(b ? s : t);
}

extern "C" int __builtin_abs(int); // #1
long __builtin_abs(long);          // #2
extern "C" int __builtin_abs(int); // #3

int x = __builtin_abs(-2);
// CHECK:  store i32 2, i32* @x, align 4

long y = __builtin_abs(-2l);
// CHECK:  [[Y:%.+]] = call i64 @_Z13__builtin_absl(i64 -2)
// CHECK:  store i64 [[Y]], i64* @y, align 8

extern const char char_memchr_arg[32];
char *memchr_result = __builtin_char_memchr(char_memchr_arg, 123, 32);
// CHECK: call i8* @memchr(i8* getelementptr inbounds ([32 x i8], [32 x i8]* @char_memchr_arg, i64 0, i64 0), i32 123, i64 32)

int constexpr_overflow_result() {
  constexpr int x = 1;
  // CHECK: alloca i32
  constexpr int y = 2;
  // CHECK: alloca i32
  int z;
  // CHECK: [[Z:%.+]] = alloca i32

  __builtin_sadd_overflow(x, y, &z);
  return z;
  // CHECK: [[RET_PTR:%.+]] = extractvalue { i32, i1 } %0, 0
  // CHECK: store i32 [[RET_PTR]], i32* [[Z]]
  // CHECK: [[RET_VAL:%.+]] = load i32, i32* [[Z]]
  // CHECK: ret i32 [[RET_VAL]]
}