clang/test/CodeGenCXX/attr-musttail.cpp

   1 // RUN: %clang_cc1 -fno-elide-constructors -S -emit-llvm %s -triple x86_64-unknown-linux-gnu -o - | FileCheck %s
   2 // RUN: %clang_cc1 -fno-elide-constructors -S -emit-llvm %s -triple x86_64-unknown-linux-gnu -o - | opt -verify
   3 // FIXME: remove the call to "opt" once the tests are running the Clang verifier automatically again.
   4
   5 int Bar(int);
   6 int Baz(int);
   7
   8 int Func1(int x) {
   9   if (x) {
  10     // CHECK: %call = musttail call noundef i32 @_Z3Bari(i32 noundef %1)
  11     // CHECK-NEXT: ret i32 %call
  12     [[clang::musttail]] return Bar(x);
  13   } else {
  14     [[clang::musttail]] return Baz(x); // CHECK: %call1 = musttail call noundef i32 @_Z3Bazi(i32 noundef %3)
  15   }
  16 }
  17
  18 int Func2(int x) {
  19   {
  20     [[clang::musttail]] return Bar(Bar(x));
  21   }
  22 }
  23
  24 // CHECK: %call1 = musttail call noundef i32 @_Z3Bari(i32 noundef %call)
  25
  26 class Foo {
  27 public:
  28   static int StaticMethod(int x);
  29   int MemberFunction(int x);
  30   int TailFrom(int x);
  31   int TailFrom2(int x);
  32   int TailFrom3(int x);
  33 };
  34
  35 int Foo::TailFrom(int x) {
  36   [[clang::musttail]] return MemberFunction(x);
  37 }
  38
  39 // CHECK: %call = musttail call noundef i32 @_ZN3Foo14MemberFunctionEi(%class.Foo* noundef nonnull align 1 dereferenceable(1) %this1, i32 noundef %0)
  40
  41 int Func3(int x) {
  42   [[clang::musttail]] return Foo::StaticMethod(x);
  43 }
  44
  45 // CHECK: %call = musttail call noundef i32 @_ZN3Foo12StaticMethodEi(i32 noundef %0)
  46
  47 int Func4(int x) {
  48   Foo foo; // Object with trivial destructor.
  49   [[clang::musttail]] return foo.StaticMethod(x);
  50 }
  51
  52 // CHECK: %call = musttail call noundef i32 @_ZN3Foo12StaticMethodEi(i32 noundef %0)
  53
  54 int (Foo::*pmf)(int);
  55
  56 int Foo::TailFrom2(int x) {
  57   [[clang::musttail]] return ((*this).*pmf)(x);
  58 }
  59
  60 // CHECK: %call = musttail call noundef i32 %8(%class.Foo* noundef nonnull align 1 dereferenceable(1) %this.adjusted, i32 noundef %9)
  61
  62 int Foo::TailFrom3(int x) {
  63   [[clang::musttail]] return (this->*pmf)(x);
  64 }
  65
  66 // CHECK: %call = musttail call noundef i32 %8(%class.Foo* noundef nonnull align 1 dereferenceable(1) %this.adjusted, i32 noundef %9)
  67
  68 void ReturnsVoid();
  69
  70 void Func5() {
  71   [[clang::musttail]] return ReturnsVoid();
  72 }
  73
  74 // CHECK: musttail call void @_Z11ReturnsVoidv()
  75
  76 class HasTrivialDestructor {};
  77
  78 int ReturnsInt(int x);
  79
  80 int Func6(int x) {
  81   HasTrivialDestructor foo;
  82   [[clang::musttail]] return ReturnsInt(x);
  83 }
  84
  85 // CHECK: %call = musttail call noundef i32 @_Z10ReturnsInti(i32 noundef %0)
  86
  87 struct Data {
  88   int (*fptr)(Data *);
  89 };
  90
  91 int Func7(Data *data) {
  92   [[clang::musttail]] return data->fptr(data);
  93 }
  94
  95 // CHECK: %call = musttail call noundef i32 %1(%struct.Data* noundef %2)
  96
  97 template <class T>
  98 T TemplateFunc(T) {
  99   return 5;
 100 }
 101
 102 int Func9(int x) {
 103   [[clang::musttail]] return TemplateFunc<int>(x);
 104 }
 105
 106 // CHECK: %call = musttail call noundef i32 @_Z12TemplateFuncIiET_S0_(i32 noundef %0)
 107
 108 template <class T>
 109 int Func10(int x) {
 110   T t;
 111   [[clang::musttail]] return Bar(x);
 112 }
 113
 114 int Func11(int x) {
 115   return Func10<int>(x);
 116 }
 117
 118 // CHECK: %call = musttail call noundef i32 @_Z3Bari(i32 noundef %0)
 119
 120 template <class T>
 121 T Func12(T x) {
 122   [[clang::musttail]] return ::Bar(x);
 123 }
 124
 125 int Func13(int x) {
 126   return Func12<int>(x);
 127 }
 128
 129 // CHECK: %call = musttail call noundef i32 @_Z3Bari(i32 noundef %0)
 130
 131 int Func14(int x) {
 132   int vla[x];
 133   [[clang::musttail]] return Bar(x);
 134 }
 135
 136 // CHECK: %call = musttail call noundef i32 @_Z3Bari(i32 noundef %3)
 137
 138 void TrivialDestructorParam(HasTrivialDestructor obj);
 139
 140 void Func14(HasTrivialDestructor obj) {
 141   [[clang::musttail]] return TrivialDestructorParam(obj);
 142 }
 143
 144 // CHECK: musttail call void @_Z22TrivialDestructorParam20HasTrivialDestructor()
 145
 146 struct Struct3 {
 147   void ConstMemberFunction(const int *) const;
 148   void NonConstMemberFunction(int *i);
 149 };
 150 void Struct3::NonConstMemberFunction(int *i) {
 151   // The parameters are not identical, but they are compatible.
 152   [[clang::musttail]] return ConstMemberFunction(i);
 153 }
 154
 155 // CHECK: musttail call void @_ZNK7Struct319ConstMemberFunctionEPKi(%struct.Struct3* noundef nonnull align 1 dereferenceable(1) %this1, i32* noundef %0)
 156
 157 struct HasNonTrivialCopyConstructor {
 158   HasNonTrivialCopyConstructor(const HasNonTrivialCopyConstructor &);
 159 };
 160 HasNonTrivialCopyConstructor ReturnsClassByValue();
 161 HasNonTrivialCopyConstructor TestNonElidableCopyConstructor() {
 162   [[clang::musttail]] return (((ReturnsClassByValue())));
 163 }
 164
 165 // CHECK: musttail call void @_Z19ReturnsClassByValuev(%struct.HasNonTrivialCopyConstructor* sret(%struct.HasNonTrivialCopyConstructor) align 1 %agg.result)
 166
 167 struct HasNonTrivialCopyConstructor2 {
 168   // Copy constructor works even if it has extra default params.
 169   HasNonTrivialCopyConstructor2(const HasNonTrivialCopyConstructor &, int DefaultParam = 5);
 170 };
 171 HasNonTrivialCopyConstructor2 ReturnsClassByValue2();
 172 HasNonTrivialCopyConstructor2 TestNonElidableCopyConstructor2() {
 173   [[clang::musttail]] return (((ReturnsClassByValue2())));
 174 }
 175
 176 // CHECK: musttail call void @_Z20ReturnsClassByValue2v()
 177
 178 void TestFunctionPointer(int x) {
 179   void (*p)(int) = nullptr;
 180   [[clang::musttail]] return p(x);
 181 }
 182
 183 // CHECK: musttail call void %0(i32 noundef %1)
 184
 185 struct LargeWithCopyConstructor {
 186   LargeWithCopyConstructor(const LargeWithCopyConstructor &);
 187   char data[32];
 188 };
 189 LargeWithCopyConstructor ReturnsLarge();
 190 LargeWithCopyConstructor TestLargeWithCopyConstructor() {
 191   [[clang::musttail]] return ReturnsLarge();
 192 }
 193
 194 // CHECK: define dso_local void @_Z28TestLargeWithCopyConstructorv(%struct.LargeWithCopyConstructor* noalias sret(%struct.LargeWithCopyConstructor) align 1 %agg.result)
 195 // CHECK: musttail call void @_Z12ReturnsLargev(%struct.LargeWithCopyConstructor* sret(%struct.LargeWithCopyConstructor) align 1 %agg.result)
 196
 197 using IntFunctionType = int();
 198 IntFunctionType *ReturnsIntFunction();
 199 int TestRValueFunctionPointer() {
 200   [[clang::musttail]] return ReturnsIntFunction()();
 201 }
 202
 203 // CHECK: musttail call noundef i32 %call()
 204
 205 void(FuncWithParens)() {
 206   [[clang::musttail]] return FuncWithParens();
 207 }
 208
 209 // CHECK: musttail call void @_Z14FuncWithParensv()
 210
 211 int TestNonCapturingLambda() {
 212   auto lambda = []() { return 12; };
 213   [[clang::musttail]] return (+lambda)();
 214 }
 215
 216 // CHECK: %call = call noundef i32 ()* @"_ZZ22TestNonCapturingLambdavENK3$_0cvPFivEEv"(%class.anon* noundef nonnull align 1 dereferenceable(1) %lambda)
 217 // CHECK: musttail call noundef i32 %call()
 218
 219 class TestVirtual {
 220   virtual void TailTo();
 221   virtual void TailFrom();
 222 };
 223
 224 void TestVirtual::TailFrom() {
 225   [[clang::musttail]] return TailTo();
 226 }
 227
 228 // CHECK: musttail call void %1(%class.TestVirtual* noundef nonnull align 8 dereferenceable(8) %this1)