clang/test/Sema/builtin-expect-with-probability.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify %s
   2
   3 __attribute__((noreturn)) extern void bar();
   4
   5 int test_no_warn(int x) {
   6   if (x) {
   7     if (__builtin_expect_with_probability(1, 1, 1))
   8       bar();
   9   } else {
  10     return 0;
  11   }
  12 } // should not emit warn "control may reach end of non-void function" here since expr is constantly true, so the "if(__bui..)" should be constantly true condition and be ignored
  13
  14 template <int b> void tempf() {
  15   static_assert(b == 1, "should be evaluated as 1"); // should not have error here
  16 }
  17
  18 constexpr int constf() {
  19   return __builtin_expect_with_probability(1, 1, 1);
  20 }
  21
  22 void foo() {
  23   tempf<__builtin_expect_with_probability(1, 1, 1)>();
  24   constexpr int f = constf();
  25   static_assert(f == 1, "should be evaluated as 1"); // should not have error here
  26 }
  27
  28 extern int global;
  29
  30 struct S {
  31   static constexpr float prob = 0.7;
  32 };
  33
  34 template<typename T>
  35 void expect_taken(int x) {
  36   if (__builtin_expect_with_probability(x > 0, 1, T::prob)) {
  37     global++;
  38   }
  39 }
  40
  41 void test(int x, double p) { // expected-note {{declared here}}
  42   bool dummy;
  43   dummy = __builtin_expect_with_probability(x > 0, 1, 0.9);
  44   dummy = __builtin_expect_with_probability(x > 0, 1, 1.1); // expected-error {{probability argument to __builtin_expect_with_probability is outside the range [0.0, 1.0]}}
  45   dummy = __builtin_expect_with_probability(x > 0, 1, -1); // expected-error {{probability argument to __builtin_expect_with_probability is outside the range [0.0, 1.0]}}
  46   dummy = __builtin_expect_with_probability(x > 0, 1, p); // expected-error {{probability argument to __builtin_expect_with_probability must be constant floating-point expression}} expected-note {{function parameter 'p'}}
  47   dummy = __builtin_expect_with_probability(x > 0, 1, "aa"); // expected-error {{cannot initialize a parameter of type 'double' with an lvalue of type 'const char[3]'}}
  48   dummy = __builtin_expect_with_probability(x > 0, 1, __builtin_nan("")); // expected-error {{probability argument to __builtin_expect_with_probability is outside the range [0.0, 1.0]}}
  49   dummy = __builtin_expect_with_probability(x > 0, 1, __builtin_inf()); // expected-error {{probability argument to __builtin_expect_with_probability is outside the range [0.0, 1.0]}}
  50   dummy = __builtin_expect_with_probability(x > 0, 1, -0.0);
  51   dummy = __builtin_expect_with_probability(x > 0, 1, 1.0 + __DBL_EPSILON__); // expected-error {{probability argument to __builtin_expect_with_probability is outside the range [0.0, 1.0]}}
  52   dummy = __builtin_expect_with_probability(x > 0, 1, -__DBL_DENORM_MIN__); // expected-error {{probability argument to __builtin_expect_with_probability is outside the range [0.0, 1.0]}}
  53   constexpr double pd = 0.7;
  54   dummy = __builtin_expect_with_probability(x > 0, 1, pd);
  55   constexpr int pi = 1;
  56   dummy = __builtin_expect_with_probability(x > 0, 1, pi);
  57   expect_taken<S>(x);
  58 }