xref: /llvm-project/llvm/test/Transforms/SimplifyCFG/basictest.ll (revision 07b9d231ff9baa6473b0dd588a3ce5330d3e4871)
1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
2; Test CFG simplify removal of branch instructions.
3;
4; RUN: opt < %s -passes=simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
5; RUN: opt < %s -passes=simplifycfg -S | FileCheck %s
6
7define void @test1() {
8; CHECK-LABEL: @test1(
9; CHECK-NEXT:    ret void
10;
11  br label %1
12  ret void
13}
14
15define void @test2() {
16; CHECK-LABEL: @test2(
17; CHECK-NEXT:    ret void
18;
19  ret void
20  ret void
21}
22
23define void @test3(i1 %T) {
24; CHECK-LABEL: @test3(
25; CHECK-NEXT:    ret void
26;
27  br i1 %T, label %1, label %1
28  ret void
29}
30
31; Folding branch to a common destination.
32define void @test4_fold(i32 %a, i32 %b) {
33; CHECK-LABEL: @test4_fold(
34; CHECK-NEXT:    [[CMP1:%.*]] = icmp eq i32 [[A:%.*]], [[B:%.*]]
35; CHECK-NEXT:    [[CMP2:%.*]] = icmp ugt i32 [[A]], 0
36; CHECK-NEXT:    [[OR_COND:%.*]] = and i1 [[CMP1]], [[CMP2]]
37; CHECK-NEXT:    br i1 [[OR_COND]], label [[ELSE:%.*]], label [[COMMON_RET:%.*]]
38; CHECK:       common.ret:
39; CHECK-NEXT:    ret void
40; CHECK:       else:
41; CHECK-NEXT:    call void @foo()
42; CHECK-NEXT:    br label [[COMMON_RET]]
43;
44  %cmp1 = icmp eq i32 %a, %b
45  br i1 %cmp1, label %taken, label %untaken
46
47taken:
48  %cmp2 = icmp ugt i32 %a, 0
49  br i1 %cmp2, label %else, label %untaken
50
51else:
52  call void @foo()
53  ret void
54
55untaken:
56  ret void
57}
58
59; Prefer a simplification based on a dominating condition rather than folding a
60; branch to a common destination.
61define void @test4_no_fold(i32 %a, i32 %b) {
62; CHECK-LABEL: @test4_no_fold(
63; CHECK-NEXT:  untaken:
64; CHECK-NEXT:    [[CMP1:%.*]] = icmp eq i32 [[A:%.*]], [[B:%.*]]
65; CHECK-NEXT:    ret void
66;
67  %cmp1 = icmp eq i32 %a, %b
68  br i1 %cmp1, label %taken, label %untaken
69
70taken:
71  %cmp2 = icmp ugt i32 %a, %b
72  br i1 %cmp2, label %else, label %untaken
73
74else:
75  call void @foo()
76  ret void
77
78untaken:
79  ret void
80}
81
82declare void @foo()
83
84; PR5795
85define void @test5(i32 %A) {
86; CHECK-LABEL: @test5(
87; CHECK-NEXT:  common.ret:
88; CHECK-NEXT:    ret void
89;
90  switch i32 %A, label %return [
91  i32 2, label %1
92  i32 10, label %2
93  ]
94
95  ret void
96
97  ret void
98
99return:                                           ; preds = %entry
100  ret void
101}
102
103
104; PR14893
105define i8 @test6f() {
106; CHECK-LABEL: @test6f(
107; CHECK-NEXT:  bb0:
108; CHECK-NEXT:    [[R:%.*]] = alloca i8, align 1
109; CHECK-NEXT:    [[TMP:%.*]] = call i8 @test6g(ptr [[R]])
110; CHECK-NEXT:    [[TMP1:%.*]] = icmp eq i8 [[TMP]], 0
111; CHECK-NEXT:    [[TMP3:%.*]] = load i8, ptr [[R]], align 1, !range [[RNG5:![0-9]+]]
112; CHECK-NEXT:    [[TMP4:%.*]] = icmp eq i8 [[TMP3]], 1
113; CHECK-NEXT:    [[OR_COND:%.*]] = select i1 [[TMP1]], i1 true, i1 [[TMP4]]
114; CHECK-NEXT:    [[TMP6:%.*]] = select i1 [[OR_COND]], i8 0, i8 1
115; CHECK-NEXT:    ret i8 [[TMP6]]
116;
117
118bb0:
119  %r = alloca i8, align 1
120  %tmp = call i8 @test6g(ptr %r)
121  %tmp1 = icmp eq i8 %tmp, 0
122  br i1 %tmp1, label %bb2, label %bb1
123bb1:
124  %tmp3 = load i8, ptr %r, align 1, !range !2, !tbaa !10, !dbg !5
125  %tmp4 = icmp eq i8 %tmp3, 1
126  br i1 %tmp4, label %bb2, label %bb3
127bb2:
128  br label %bb3
129bb3:
130  %tmp6 = phi i8 [ 0, %bb2 ], [ 1, %bb1 ]
131  ret i8 %tmp6
132}
133declare i8 @test6g(ptr)
134
135!llvm.dbg.cu = !{!3}
136!llvm.module.flags = !{!8, !9}
137
138!0 = !{!10, !10, i64 0}
139!1 = !{!"foo"}
140!2 = !{i8 0, i8 2}
141!3 = distinct !DICompileUnit(language: DW_LANG_C99, file: !7, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !4)
142!4 = !{}
143!5 = !DILocation(line: 23, scope: !6)
144!6 = distinct !DISubprogram(name: "foo", scope: !3, file: !7, line: 1, type: !DISubroutineType(types: !4), isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !3, retainedNodes: !4)
145!7 = !DIFile(filename: "foo.c", directory: "/")
146!8 = !{i32 2, !"Dwarf Version", i32 2}
147!9 = !{i32 2, !"Debug Info Version", i32 3}
148!10 = !{!"scalar type", !1}
149