xref: /llvm-project/llvm/test/Transforms/GlobalOpt/invariant.group.ll (revision d586bd5ca231a6022f439d4c6e43cfeeb53eb1d6) 
1; RUN: opt -S -passes=globalopt < %s | FileCheck %s
2
3; CHECK: @llvm.global_ctors = appending global [1 x {{.*}}@_GLOBAL__I_c
4@llvm.global_ctors = appending global [3 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 65535, ptr @_GLOBAL__I_a, ptr null }, { i32, ptr, ptr } { i32 65535, ptr @_GLOBAL__I_b, ptr null }, { i32, ptr, ptr } { i32 65535, ptr @_GLOBAL__I_c, ptr null }]
5
6; CHECK: @tmp = local_unnamed_addr global i32 42
7; CHECK: @tmp2 = local_unnamed_addr global i32 42
8; CHECK: @tmp3 = global i32 42
9@tmp = global i32 0
10@tmp2 = global i32 0
11@tmp3 = global i32 0
12@ptrToTmp3 = global ptr null
13
14define i32 @TheAnswerToLifeTheUniverseAndEverything() {
15  ret i32 42
16}
17
18define void @_GLOBAL__I_a() {
19enter:
20  call void @_optimizable()
21  call void @_not_optimizable()
22  ret void
23}
24
25define void @_optimizable() {
26enter:
27  %valptr = alloca i32
28
29  %val = call i32 @TheAnswerToLifeTheUniverseAndEverything()
30  store i32 %val, ptr @tmp
31  store i32 %val, ptr %valptr
32
33  %barr = call ptr @llvm.launder.invariant.group(ptr %valptr)
34
35  %val2 = load i32, ptr %barr
36  store i32 %val2, ptr @tmp2
37  ret void
38}
39
40; We can't step through launder.invariant.group here, because that would change
41; this load in @usage_of_globals()
42; %val = load i32, ptr %ptrVal, !invariant.group !0
43; into
44; %val = load i32, ptr @tmp3, !invariant.group !0
45; and then we could assume that %val and %val2 to be the same, which coud be
46; false, because @changeTmp3ValAndCallBarrierInside() may change the value
47; of @tmp3.
48define void @_not_optimizable() {
49enter:
50  store i32 13, ptr @tmp3, !invariant.group !0
51
52  %barr = call ptr @llvm.launder.invariant.group(ptr @tmp3)
53
54  store ptr %barr, ptr @ptrToTmp3
55  store i32 42, ptr %barr, !invariant.group !0
56
57  ret void
58}
59
60define void @usage_of_globals() {
61entry:
62  %ptrVal = load ptr, ptr @ptrToTmp3
63  %val = load i32, ptr %ptrVal, !invariant.group !0
64
65  call void @changeTmp3ValAndCallBarrierInside()
66  %val2 = load i32, ptr @tmp3, !invariant.group !0
67  ret void;
68}
69
70@tmp4 = global i32 0
71
72define void @_GLOBAL__I_b() {
73enter:
74  %val = call i32 @TheAnswerToLifeTheUniverseAndEverything()
75  %p2 = call ptr @llvm.strip.invariant.group.p0(ptr @tmp4)
76  store i32 %val, ptr %p2
77  ret void
78}
79
80@tmp5 = global i32 0
81@tmp6 = global ptr null
82; CHECK: @tmp6 = local_unnamed_addr global ptr null
83
84define ptr @_dont_return_param(ptr %p) {
85  %p2 = call ptr @llvm.launder.invariant.group(ptr %p)
86  ret ptr %p2
87}
88
89; We should bail out if we return any pointers derived via invariant.group intrinsics at any point.
90define void @_GLOBAL__I_c() {
91enter:
92  %tmp5 = call ptr @_dont_return_param(ptr @tmp5)
93  store ptr %tmp5, ptr @tmp6
94  ret void
95}
96
97
98declare void @changeTmp3ValAndCallBarrierInside()
99
100declare ptr @llvm.launder.invariant.group(ptr)
101declare ptr @llvm.strip.invariant.group.p0(ptr)
102
103!0 = !{}
104