clang/test/CodeGenCXX/cxx2b-consteval-if.cpp

   1 // RUN: %clang_cc1 -std=c++23 %s -emit-llvm -o - | FileCheck %s
   2
   3 void should_be_used_1();
   4 void should_be_used_2();
   5 void should_be_used_3();
   6 constexpr void should_not_be_used() {}
   7
   8 constexpr void f() {
   9   if consteval {
  10     should_not_be_used(); // CHECK-NOT: call {{.*}}should_not_be_used
  11   } else {
  12     should_be_used_1();  // CHECK: call {{.*}}should_be_used_1
  13   }
  14
  15   if !consteval {
  16     should_be_used_2();  // CHECK: call {{.*}}should_be_used_2
  17   }
  18
  19   if !consteval {
  20     should_be_used_3();  // CHECK: call {{.*}}should_be_used_3
  21   } else {
  22     should_not_be_used(); // CHECK-NOT: call {{.*}}should_not_be_used
  23   }
  24 }
  25
  26 void g() {
  27   f();
  28 }
  29
  30 namespace GH55638 {
  31
  32 constexpr bool is_constant_evaluated() noexcept {
  33   if consteval { return true; } else { return false; }
  34 }
  35
  36 constexpr int compiletime(int) {
  37    return 2;
  38 }
  39
  40 constexpr int runtime(int) {
  41    return 1;
  42 }
  43
  44 constexpr int test(int x) {
  45   if(is_constant_evaluated())
  46     return compiletime(x);  // CHECK-NOT: call {{.*}}compiletime
  47    return runtime(x);  // CHECK: call {{.*}}runtime
  48 }
  49
  50 int f(int x) {
  51   x = test(x);
  52   return x;
  53 }
  54
  55 }