1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
2; Test that the strlen library call simplifier works correctly.
3;
4; RUN: opt < %s -instcombine -S | FileCheck %s
5
6target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
7
8@hello = constant [6 x i8] c"hello\00"
9@longer = constant [7 x i8] c"longer\00"
10@null = constant [1 x i8] zeroinitializer
11@null_hello = constant [7 x i8] c"\00hello\00"
12@nullstring = constant i8 0
13@a = common global [32 x i8] zeroinitializer, align 1
14@null_hello_mid = constant [13 x i8] c"hello wor\00ld\00"
15
16declare i32 @strlen(i8*)
17
18; Check strlen(string constant) -> integer constant.
19
20define i32 @test_simplify1() {
21; CHECK-LABEL: @test_simplify1(
22; CHECK-NEXT:    ret i32 5
23;
24  %hello_p = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
25  %hello_l = call i32 @strlen(i8* %hello_p)
26  ret i32 %hello_l
27}
28
29define i32 @test_simplify2() {
30; CHECK-LABEL: @test_simplify2(
31; CHECK-NEXT:    ret i32 0
32;
33  %null_p = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0
34  %null_l = call i32 @strlen(i8* %null_p)
35  ret i32 %null_l
36}
37
38define i32 @test_simplify3() {
39; CHECK-LABEL: @test_simplify3(
40; CHECK-NEXT:    ret i32 0
41;
42  %null_hello_p = getelementptr [7 x i8], [7 x i8]* @null_hello, i32 0, i32 0
43  %null_hello_l = call i32 @strlen(i8* %null_hello_p)
44  ret i32 %null_hello_l
45}
46
47define i32 @test_simplify4() {
48; CHECK-LABEL: @test_simplify4(
49; CHECK-NEXT:    ret i32 0
50;
51  %len = tail call i32 @strlen(i8* @nullstring) nounwind
52  ret i32 %len
53}
54
55; Check strlen(x) == 0 --> *x == 0.
56
57define i1 @test_simplify5() {
58; CHECK-LABEL: @test_simplify5(
59; CHECK-NEXT:    ret i1 false
60;
61  %hello_p = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
62  %hello_l = call i32 @strlen(i8* %hello_p)
63  %eq_hello = icmp eq i32 %hello_l, 0
64  ret i1 %eq_hello
65}
66
67define i1 @test_simplify6() {
68; CHECK-LABEL: @test_simplify6(
69; CHECK-NEXT:    ret i1 true
70;
71  %null_p = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0
72  %null_l = call i32 @strlen(i8* %null_p)
73  %eq_null = icmp eq i32 %null_l, 0
74  ret i1 %eq_null
75}
76
77; Check strlen(x) != 0 --> *x != 0.
78
79define i1 @test_simplify7() {
80; CHECK-LABEL: @test_simplify7(
81; CHECK-NEXT:    ret i1 true
82;
83  %hello_p = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
84  %hello_l = call i32 @strlen(i8* %hello_p)
85  %ne_hello = icmp ne i32 %hello_l, 0
86  ret i1 %ne_hello
87}
88
89define i1 @test_simplify8() {
90; CHECK-LABEL: @test_simplify8(
91; CHECK-NEXT:    ret i1 false
92;
93  %null_p = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0
94  %null_l = call i32 @strlen(i8* %null_p)
95  %ne_null = icmp ne i32 %null_l, 0
96  ret i1 %ne_null
97}
98
99define i32 @test_simplify9(i1 %x) {
100; CHECK-LABEL: @test_simplify9(
101; CHECK-NEXT:    [[TMP1:%.*]] = select i1 %x, i32 5, i32 6
102; CHECK-NEXT:    ret i32 [[TMP1]]
103;
104  %hello = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
105  %longer = getelementptr [7 x i8], [7 x i8]* @longer, i32 0, i32 0
106  %s = select i1 %x, i8* %hello, i8* %longer
107  %l = call i32 @strlen(i8* %s)
108  ret i32 %l
109}
110
111; Check the case that should be simplified to a sub instruction.
112; strlen(@hello + x) --> 5 - x
113
114define i32 @test_simplify10(i32 %x) {
115; CHECK-LABEL: @test_simplify10(
116; CHECK-NEXT:    [[TMP1:%.*]] = sub i32 5, %x
117; CHECK-NEXT:    ret i32 [[TMP1]]
118;
119  %hello_p = getelementptr inbounds [6 x i8], [6 x i8]* @hello, i32 0, i32 %x
120  %hello_l = call i32 @strlen(i8* %hello_p)
121  ret i32 %hello_l
122}
123
124; strlen(@null_hello_mid + (x & 7)) --> 9 - (x & 7)
125
126define i32 @test_simplify11(i32 %x) {
127; CHECK-LABEL: @test_simplify11(
128; CHECK-NEXT:    [[AND:%.*]] = and i32 %x, 7
129; CHECK-NEXT:    [[TMP1:%.*]] = sub nsw i32 9, [[AND]]
130; CHECK-NEXT:    ret i32 [[TMP1]]
131;
132  %and = and i32 %x, 7
133  %hello_p = getelementptr inbounds [13 x i8], [13 x i8]* @null_hello_mid, i32 0, i32 %and
134  %hello_l = call i32 @strlen(i8* %hello_p)
135  ret i32 %hello_l
136}
137
138; Check cases that shouldn't be simplified.
139
140define i32 @test_no_simplify1() {
141; CHECK-LABEL: @test_no_simplify1(
142; CHECK-NEXT:    [[A_L:%.*]] = call i32 @strlen(i8* getelementptr inbounds ([32 x i8], [32 x i8]* @a, i32 0, i32 0))
143; CHECK-NEXT:    ret i32 [[A_L]]
144;
145  %a_p = getelementptr [32 x i8], [32 x i8]* @a, i32 0, i32 0
146  %a_l = call i32 @strlen(i8* %a_p)
147  ret i32 %a_l
148}
149
150; strlen(@null_hello + x) should not be simplified to a sub instruction.
151
152define i32 @test_no_simplify2(i32 %x) {
153; CHECK-LABEL: @test_no_simplify2(
154; CHECK-NEXT:    [[HELLO_P:%.*]] = getelementptr inbounds [7 x i8], [7 x i8]* @null_hello, i32 0, i32 %x
155; CHECK-NEXT:    [[HELLO_L:%.*]] = call i32 @strlen(i8* [[HELLO_P]])
156; CHECK-NEXT:    ret i32 [[HELLO_L]]
157;
158  %hello_p = getelementptr inbounds [7 x i8], [7 x i8]* @null_hello, i32 0, i32 %x
159  %hello_l = call i32 @strlen(i8* %hello_p)
160  ret i32 %hello_l
161}
162
163; strlen(@null_hello_mid + (x & 15)) should not be simplified to a sub instruction.
164
165define i32 @test_no_simplify3(i32 %x) {
166; CHECK-LABEL: @test_no_simplify3(
167; CHECK-NEXT:    [[AND:%.*]] = and i32 %x, 15
168; CHECK-NEXT:    [[HELLO_P:%.*]] = getelementptr inbounds [13 x i8], [13 x i8]* @null_hello_mid, i32 0, i32 [[AND]]
169; CHECK-NEXT:    [[HELLO_L:%.*]] = call i32 @strlen(i8* [[HELLO_P]])
170; CHECK-NEXT:    ret i32 [[HELLO_L]]
171;
172  %and = and i32 %x, 15
173  %hello_p = getelementptr inbounds [13 x i8], [13 x i8]* @null_hello_mid, i32 0, i32 %and
174  %hello_l = call i32 @strlen(i8* %hello_p)
175  ret i32 %hello_l
176}
177
178