clang/test/CodeGenCXX/builtin-std-move.cpp

   1 // RUN: %clang_cc1 -triple=x86_64-linux-gnu -emit-llvm -o - -std=c++17 %s | FileCheck %s --implicit-check-not=@_ZSt4move
   2
   3 namespace std {
   4   template<typename T> constexpr T &&move(T &val) { return static_cast<T&&>(val); }
   5   template<typename T> constexpr T &&move_if_noexcept(T &val);
   6   template<typename T> constexpr T &&forward(T &val);
   7   template<typename U, typename T> constexpr T &&forward_like(T &&val);
   8   template<typename T> constexpr const T &as_const(T &val);
   9
  10   // Not the builtin.
  11   template<typename T, typename U> T move(U source, U source_end, T dest);
  12 }
  13
  14 class T {};
  15 extern "C" void take(T &&);
  16 extern "C" void take_lval(const T &);
  17
  18 T a;
  19
  20 // Check emission of a constant-evaluated call.
  21 // CHECK-DAG: @move_a = constant ptr @a
  22 T &&move_a = std::move(a);
  23 // CHECK-DAG: @move_if_noexcept_a = constant ptr @a
  24 T &&move_if_noexcept_a = std::move_if_noexcept(a);
  25 // CHECK-DAG: @forward_a = constant ptr @a
  26 T &forward_a = std::forward<T&>(a);
  27 // CHECK-DAG: @forward_like_a = constant ptr @a
  28 T &forward_like_a = std::forward_like<int&>(a);
  29
  30 // Check emission of a non-constant call.
  31 // CHECK-LABEL: define {{.*}} void @test
  32 extern "C" void test(T &t) {
  33   // CHECK: store ptr %{{.*}}, ptr %[[T_REF:[^,]*]]
  34   // CHECK: %0 = load ptr, ptr %[[T_REF]]
  35   // CHECK: call void @take(ptr {{.*}} %0)
  36   take(std::move(t));
  37   // CHECK: %1 = load ptr, ptr %[[T_REF]]
  38   // CHECK: call void @take(ptr {{.*}} %1)
  39   take(std::move_if_noexcept(t));
  40   // CHECK: %2 = load ptr, ptr %[[T_REF]]
  41   // CHECK: call void @take(ptr {{.*}} %2)
  42   take(std::forward<T&&>(t));
  43   // CHECK: %3 = load ptr, ptr %[[T_REF]]
  44   // CHECK: call void @take_lval(ptr {{.*}} %3)
  45   take_lval(std::forward_like<int&>(t));
  46   // CHECK: %4 = load ptr, ptr %[[T_REF]]
  47   // CHECK: call void @take_lval(ptr {{.*}} %4)
  48   take_lval(std::as_const<T&&>(t));
  49
  50   // CHECK: call {{.*}} @_ZSt4moveI1TS0_ET_T0_S2_S1_
  51   std::move(t, t, t);
  52 }
  53
  54 // CHECK: declare {{.*}} @_ZSt4moveI1TS0_ET_T0_S2_S1_
  55
  56 // Check that we instantiate and emit if the address is taken.
  57 // CHECK-LABEL: define {{.*}} @use_address
  58 extern "C" void *use_address() {
  59   // CHECK: ret {{.*}} @_ZSt4moveIiEOT_RS0_
  60   return (void*)&std::move<int>;
  61 }
  62
  63 // CHECK: define {{.*}} ptr @_ZSt4moveIiEOT_RS0_(ptr
  64
  65 extern "C" void take_const_int_rref(const int &&);
  66 // CHECK-LABEL: define {{.*}} @move_const_int(
  67 extern "C" void move_const_int() {
  68   // CHECK: store i32 5, ptr %[[N_ADDR:[^,]*]]
  69   const int n = 5;
  70   // CHECK: call {{.*}} @take_const_int_rref(ptr {{.*}} %[[N_ADDR]])
  71   take_const_int_rref(std::move(n));
  72 }