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comparison clang/test/CodeGenCXX/stack-reuse.cpp @ 150:1d019706d866

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LLVM10
author anatofuz
date Thu, 13 Feb 2020 15:10:13 +0900
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children 0572611fdcc8
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147:c2174574ed3a 150:1d019706d866
1 // RUN: %clang_cc1 -triple armv7-unknown-linux-gnueabihf %s -o - -emit-llvm -O2 | FileCheck %s
2
3 // Stack should be reused when possible, no need to allocate two separate slots
4 // if they have disjoint lifetime.
5
6 // Sizes of objects are related to previously existed threshold of 32. In case
7 // of S_large stack size is rounded to 40 bytes.
8
9 // 32B
10 struct S_small {
11 int a[8];
12 };
13
14 // 36B
15 struct S_large {
16 int a[9];
17 };
18
19 // Helper class for lifetime scope absence testing
20 struct Combiner {
21 S_large a, b;
22
23 Combiner(S_large);
24 Combiner f();
25 };
26
27 extern S_small foo_small();
28 extern S_large foo_large();
29 extern void bar_small(S_small*);
30 extern void bar_large(S_large*);
31
32 // Prevent mangling of function names.
33 extern "C" {
34
35 void small_rvoed_unnamed_temporary_object() {
36 // CHECK-LABEL: define void @small_rvoed_unnamed_temporary_object
37 // CHECK: call void @llvm.lifetime.start
38 // CHECK: call void @_Z9foo_smallv
39 // CHECK: call void @llvm.lifetime.end
40 // CHECK: call void @llvm.lifetime.start
41 // CHECK: call void @_Z9foo_smallv
42 // CHECK: call void @llvm.lifetime.end
43
44 foo_small();
45 foo_small();
46 }
47
48 void large_rvoed_unnamed_temporary_object() {
49 // CHECK-LABEL: define void @large_rvoed_unnamed_temporary_object
50 // CHECK: call void @llvm.lifetime.start
51 // CHECK: call void @_Z9foo_largev
52 // CHECK: call void @llvm.lifetime.end
53 // CHECK: call void @llvm.lifetime.start
54 // CHECK: call void @_Z9foo_largev
55 // CHECK: call void @llvm.lifetime.end
56
57 foo_large();
58 foo_large();
59 }
60
61 void small_rvoed_named_temporary_object() {
62 // CHECK-LABEL: define void @small_rvoed_named_temporary_object
63 // CHECK: call void @llvm.lifetime.start
64 // CHECK: call void @_Z9foo_smallv
65 // CHECK: call void @llvm.lifetime.end
66 // CHECK: call void @llvm.lifetime.start
67 // CHECK: call void @_Z9foo_smallv
68 // CHECK: call void @llvm.lifetime.end
69
70 {
71 S_small s = foo_small();
72 }
73 {
74 S_small s = foo_small();
75 }
76 }
77
78 void large_rvoed_named_temporary_object() {
79 // CHECK-LABEL: define void @large_rvoed_named_temporary_object
80 // CHECK: call void @llvm.lifetime.start
81 // CHECK: call void @_Z9foo_largev
82 // CHECK: call void @llvm.lifetime.end
83 // CHECK: call void @llvm.lifetime.start
84 // CHECK: call void @_Z9foo_largev
85 // CHECK: call void @llvm.lifetime.end
86
87 {
88 S_large s = foo_large();
89 }
90 {
91 S_large s = foo_large();
92 }
93 }
94
95 void small_auto_object() {
96 // CHECK-LABEL: define void @small_auto_object
97 // CHECK: call void @llvm.lifetime.start
98 // CHECK: call void @_Z9bar_smallP7S_small
99 // CHECK: call void @llvm.lifetime.end
100 // CHECK: call void @llvm.lifetime.start
101 // CHECK: call void @_Z9bar_smallP7S_small
102 // CHECK: call void @llvm.lifetime.end
103
104 {
105 S_small s;
106 bar_small(&s);
107 }
108 {
109 S_small s;
110 bar_small(&s);
111 }
112 }
113
114 void large_auto_object() {
115 // CHECK-LABEL: define void @large_auto_object
116 // CHECK: call void @llvm.lifetime.start
117 // CHECK: call void @_Z9bar_largeP7S_large
118 // CHECK: call void @llvm.lifetime.end
119 // CHECK: call void @llvm.lifetime.start
120 // CHECK: call void @_Z9bar_largeP7S_large
121 // CHECK: call void @llvm.lifetime.end
122
123 {
124 S_large s;
125 bar_large(&s);
126 }
127 {
128 S_large s;
129 bar_large(&s);
130 }
131 }
132
133 int large_combiner_test(S_large s) {
134 // CHECK-LABEL: define i32 @large_combiner_test
135 // CHECK: [[T2:%.*]] = alloca %struct.Combiner
136 // CHECK: [[T1:%.*]] = alloca %struct.Combiner
137 // CHECK: [[T3:%.*]] = call %struct.Combiner* @_ZN8CombinerC1E7S_large(%struct.Combiner* nonnull [[T1]], [9 x i32] %s.coerce)
138 // CHECK: call void @_ZN8Combiner1fEv(%struct.Combiner* nonnull sret [[T2]], %struct.Combiner* nonnull [[T1]])
139 // CHECK: [[T4:%.*]] = getelementptr inbounds %struct.Combiner, %struct.Combiner* [[T2]], i32 0, i32 0, i32 0, i32 0
140 // CHECK: [[T5:%.*]] = load i32, i32* [[T4]]
141 // CHECK: ret i32 [[T5]]
142
143 return Combiner(s).f().a.a[0];
144 }
145
146 }