summaryrefslogtreecommitdiffstats
path: root/test/CodeGenCXX/nrvo.cpp
blob: aad287dc3206ca4bc5b9e6ecde47370a556566b8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
// RUN: %clang_cc1 -triple i386-unknown-unknown -emit-llvm -O1 -o - %s | FileCheck %s
// RUN: %clang_cc1 -triple i386-unknown-unknown -emit-llvm -O1 -fcxx-exceptions -fexceptions -o - %s | FileCheck --check-prefix=CHECK-EH %s

// Test code generation for the named return value optimization.
class X {
public:
  X();
  X(const X&);
  ~X();
};

template<typename T> struct Y {
  Y();
  static Y f() {
    Y y;
    return y;
  }
};

// CHECK-LABEL: define void @_Z5test0v
// CHECK-EH-LABEL: define void @_Z5test0v
X test0() {
  X x;
  // CHECK:          call {{.*}} @_ZN1XC1Ev
  // CHECK-NEXT:     ret void

  // CHECK-EH:       call {{.*}} @_ZN1XC1Ev
  // CHECK-EH-NEXT:  ret void
  return x;
}

// CHECK-LABEL: define void @_Z5test1b(
// CHECK-EH-LABEL: define void @_Z5test1b(
X test1(bool B) {
  // CHECK:      tail call {{.*}} @_ZN1XC1Ev
  // CHECK-NEXT: ret void
  X x;
  if (B)
    return (x);
  return x;
  // CHECK-EH:      tail call {{.*}} @_ZN1XC1Ev
  // CHECK-EH-NEXT: ret void
}

// CHECK-LABEL: define void @_Z5test2b
// CHECK-EH-LABEL: define void @_Z5test2b
X test2(bool B) {
  // No NRVO.

  X x;
  X y;
  if (B)
    return y;
  return x;

  // CHECK: call {{.*}} @_ZN1XC1Ev
  // CHECK-NEXT: call {{.*}} @_ZN1XC1Ev
  // CHECK: call {{.*}} @_ZN1XC1ERKS_
  // CHECK: call {{.*}} @_ZN1XC1ERKS_
  // CHECK: call {{.*}} @_ZN1XD1Ev
  // CHECK: call {{.*}} @_ZN1XD1Ev
  // CHECK: ret void

  // The block ordering in the -fexceptions IR is unfortunate.

  // CHECK-EH:      call {{.*}} @_ZN1XC1Ev
  // CHECK-EH-NEXT: invoke {{.*}} @_ZN1XC1Ev
  // -> %invoke.cont, %lpad

  // %invoke.cont:
  // CHECK-EH:      br i1
  // -> %if.then, %if.end

  // %if.then: returning 'x'
  // CHECK-EH:      invoke {{.*}} @_ZN1XC1ERKS_
  // -> %cleanup, %lpad1

  // %lpad: landing pad for ctor of 'y', dtor of 'y'
  // CHECK-EH:      [[CAUGHTVAL:%.*]] = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
  // CHECK-EH-NEXT:   cleanup
  // CHECK-EH-NEXT: extractvalue { i8*, i32 } [[CAUGHTVAL]], 0
  // CHECK-EH-NEXT: extractvalue { i8*, i32 } [[CAUGHTVAL]], 1
  // CHECK-EH-NEXT: br label
  // -> %eh.cleanup

  // %lpad1: landing pad for return copy ctors, EH cleanup for 'y'
  // CHECK-EH: invoke {{.*}} @_ZN1XD1Ev
  // -> %eh.cleanup, %terminate.lpad

  // %if.end: returning 'y'
  // CHECK-EH: invoke {{.*}} @_ZN1XC1ERKS_
  // -> %cleanup, %lpad1

  // %cleanup: normal cleanup for 'y'
  // CHECK-EH: invoke {{.*}} @_ZN1XD1Ev
  // -> %invoke.cont11, %lpad

  // %invoke.cont11: normal cleanup for 'x'
  // CHECK-EH:      call {{.*}} @_ZN1XD1Ev
  // CHECK-EH-NEXT: ret void

  // %eh.cleanup:  EH cleanup for 'x'
  // CHECK-EH: invoke {{.*}} @_ZN1XD1Ev
  // -> %invoke.cont17, %terminate.lpad

  // %invoke.cont17: rethrow block for %eh.cleanup.
  // This really should be elsewhere in the function.
  // CHECK-EH:      resume { i8*, i32 }

  // %terminate.lpad: terminate landing pad.
  // CHECK-EH:      [[T0:%.*]] = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
  // CHECK-EH-NEXT:   catch i8* null
  // CHECK-EH-NEXT: [[T1:%.*]] = extractvalue { i8*, i32 } [[T0]], 0
  // CHECK-EH-NEXT: call void @__clang_call_terminate(i8* [[T1]]) [[NR_NUW:#[0-9]+]]
  // CHECK-EH-NEXT: unreachable

}

// CHECK-LABEL: define void @_Z5test3b
X test3(bool B) {
  // CHECK: tail call {{.*}} @_ZN1XC1Ev
  // CHECK-NOT: call {{.*}} @_ZN1XC1ERKS_
  // CHECK: call {{.*}} @_ZN1XC1Ev
  // CHECK: call {{.*}} @_ZN1XC1ERKS_
  if (B) {
    X y;
    return y;
  }
  // FIXME: we should NRVO this variable too.
  X x;
  return x;
}

extern "C" void exit(int) throw();

// CHECK-LABEL: define void @_Z5test4b
X test4(bool B) {
  {
    // CHECK: tail call {{.*}} @_ZN1XC1Ev
    X x;
    // CHECK: br i1
    if (B)
      return x;
  }
  // CHECK: tail call {{.*}} @_ZN1XD1Ev
  // CHECK: tail call void @exit(i32 1)
  exit(1);
}

#ifdef __EXCEPTIONS
// CHECK-EH-LABEL: define void @_Z5test5
void may_throw();
X test5() {
  try {
    may_throw();
  } catch (X x) {
    // CHECK-EH: invoke {{.*}} @_ZN1XC1ERKS_
    // CHECK-EH: call void @__cxa_end_catch()
    // CHECK-EH: ret void
    return x;
  }
}
#endif

// rdar://problem/10430868
// CHECK-LABEL: define void @_Z5test6v
X test6() {
  X a __attribute__((aligned(8)));
  return a;
  // CHECK:      [[A:%.*]] = alloca [[X:%.*]], align 8
  // CHECK-NEXT: call {{.*}} @_ZN1XC1Ev([[X]]* [[A]])
  // CHECK-NEXT: call {{.*}} @_ZN1XC1ERKS_([[X]]* {{%.*}}, [[X]]* dereferenceable({{[0-9]+}}) [[A]])
  // CHECK-NEXT: call {{.*}} @_ZN1XD1Ev([[X]]* [[A]])
  // CHECK-NEXT: ret void
}

// CHECK-LABEL: define void @_Z5test7b
X test7(bool b) {
  // CHECK: tail call {{.*}} @_ZN1XC1Ev
  // CHECK-NEXT: ret
  if (b) {
    X x;
    return x;
  }
  return X();
}

// CHECK-LABEL: define void @_Z5test8b
X test8(bool b) {
  // CHECK: tail call {{.*}} @_ZN1XC1Ev
  // CHECK-NEXT: ret
  if (b) {
    X x;
    return x;
  } else {
    X y;
    return y;
  }
}

Y<int> test9() {
  Y<int>::f();
}

// CHECK-LABEL: define linkonce_odr void @_ZN1YIiE1fEv
// CHECK: tail call {{.*}} @_ZN1YIiEC1Ev

// CHECK-EH: attributes [[NR_NUW]] = { noreturn nounwind }