1; Test if the !invariant.load metadata is maintained by GVN.
2; RUN: opt -basicaa -gvn -S < %s | FileCheck %s
3
4define i32 @test1(i32* nocapture %p, i8* nocapture %q) {
5; CHECK-LABEL: test1
6; CHECK: %x = load i32, i32* %p, align 4, !invariant.load !0
7; CHECK-NOT: %y = load
8entry:
9  %x = load i32, i32* %p, align 4, !invariant.load !0
10  %conv = trunc i32 %x to i8
11  store i8 %conv, i8* %q, align 1
12  %y = load i32, i32* %p, align 4, !invariant.load !0
13  %add = add i32 %y, 1
14  ret i32 %add
15}
16
17define i32 @test2(i32* nocapture %p, i8* nocapture %q) {
18; CHECK-LABEL: test2
19; CHECK-NOT: !invariant.load
20; CHECK-NOT: %y = load
21entry:
22  %x = load i32, i32* %p, align 4
23  %conv = trunc i32 %x to i8
24  store i8 %conv, i8* %q, align 1
25  %y = load i32, i32* %p, align 4, !invariant.load !0
26  %add = add i32 %y, 1
27  ret i32 %add
28}
29
30; With the invariant.load metadata, what would otherwise
31; be a case for PRE becomes a full redundancy.
32define i32 @test3(i1 %cnd, i32* %p, i32* %q) {
33; CHECK-LABEL: test3
34; CHECK-NOT: load
35entry:
36  %v1 = load i32, i32* %p
37  br i1 %cnd, label %bb1, label %bb2
38
39bb1:
40  store i32 5, i32* %q
41  br label %bb2
42
43bb2:
44  %v2 = load i32, i32* %p, !invariant.load !0
45  %res = sub i32 %v1, %v2
46  ret i32 %res
47}
48
49; This test is here to document a case which doesn't optimize
50; as well as it could.
51define i32 @test4(i1 %cnd, i32* %p, i32* %q) {
52; CHECK-LABEL: test4
53; %v2 is redundant, but GVN currently doesn't catch that
54entry:
55  %v1 = load i32, i32* %p, !invariant.load !0
56  br i1 %cnd, label %bb1, label %bb2
57
58bb1:
59  store i32 5, i32* %q
60  br label %bb2
61
62bb2:
63  %v2 = load i32, i32* %p
64  %res = sub i32 %v1, %v2
65  ret i32 %res
66}
67
68; Checks that we return the mustalias store as a def
69; so that it contributes to value forwarding.  Note
70; that we could and should remove the store too.
71define i32 @test5(i1 %cnd, i32* %p) {
72; CHECK-LABEL: test5
73; CHECK-LABEL: entry:
74; CHECK-NEXT: store i32 5, i32* %p
75; CHECK-NEXT: ret i32 5
76entry:
77  %v1 = load i32, i32* %p, !invariant.load !0
78  store i32 5, i32* %p ;; must alias store, want to exploit
79  %v2 = load i32, i32* %p, !invariant.load !0
80  ret i32 %v2
81}
82
83
84declare void @foo()
85
86; Clobbering (mayalias) stores, even in function calls, can be ignored
87define i32 @test6(i1 %cnd, i32* %p) {
88; CHECK-LABEL: test6
89; CHECK-LABEL: entry:
90; CHECK-NEXT: @foo
91; CHECK-NEXT: ret i32 0
92entry:
93  %v1 = load i32, i32* %p, !invariant.load !0
94  call void @foo()
95  %v2 = load i32, i32* %p, !invariant.load !0
96  %res = sub i32 %v1, %v2
97  ret i32 %res
98}
99
100declare noalias i32* @bar(...)
101
102; Same as previous, but a function with a noalias result (since they're handled
103; differently in MDA)
104define i32 @test7(i1 %cnd, i32* %p) {
105; CHECK-LABEL: test7
106; CHECK-LABEL: entry:
107; CHECK-NEXT: @bar
108; CHECK-NEXT: ret i32 0
109entry:
110  %v1 = load i32, i32* %p, !invariant.load !0
111  call i32* (...) @bar(i32* %p)
112  %v2 = load i32, i32* %p, !invariant.load !0
113  %res = sub i32 %v1, %v2
114  ret i32 %res
115}
116
117define i32 @test8(i1 %cnd, i32* %p) {
118; CHECK-LABEL: test8
119; CHECK: @bar
120; CHECK: load i32, i32* %p2, !invariant.load
121; CHECK: br label %merge
122entry:
123  %v1 = load i32, i32* %p, !invariant.load !0
124  br i1 %cnd, label %taken, label %merge
125taken:
126  %p2 = call i32* (...) @bar(i32* %p)
127  br label %merge
128merge:
129  %p3 = phi i32* [%p, %entry], [%p2, %taken]
130  %v2 = load i32, i32* %p3, !invariant.load !0
131  %res = sub i32 %v1, %v2
132  ret i32 %res
133}
134
135!0 = !{ }
136
137