xref: /llvm-project/llvm/test/Transforms/InstCombine/strlen-1.ll (revision 23a239267e8a1d20ed10d3545feaf2a2bb70b085)
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 -passes=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(ptr)
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_l = call i32 @strlen(ptr @hello)
25  ret i32 %hello_l
26}
27
28define i32 @test_simplify2() {
29; CHECK-LABEL: @test_simplify2(
30; CHECK-NEXT:    ret i32 0
31;
32  %null_l = call i32 @strlen(ptr @null)
33  ret i32 %null_l
34}
35
36define i32 @test_simplify3() {
37; CHECK-LABEL: @test_simplify3(
38; CHECK-NEXT:    ret i32 0
39;
40  %null_hello_l = call i32 @strlen(ptr @null_hello)
41  ret i32 %null_hello_l
42}
43
44define i32 @test_simplify4() {
45; CHECK-LABEL: @test_simplify4(
46; CHECK-NEXT:    ret i32 0
47;
48  %len = tail call i32 @strlen(ptr @nullstring) nounwind
49  ret i32 %len
50}
51
52; Check strlen(x) == 0 --> *x == 0.
53
54define i1 @test_simplify5() {
55; CHECK-LABEL: @test_simplify5(
56; CHECK-NEXT:    ret i1 false
57;
58  %hello_l = call i32 @strlen(ptr @hello)
59  %eq_hello = icmp eq i32 %hello_l, 0
60  ret i1 %eq_hello
61}
62
63define i1 @test_simplify6(ptr %str_p) {
64; CHECK-LABEL: @test_simplify6(
65; CHECK-NEXT:    [[CHAR0:%.*]] = load i8, ptr [[STR_P:%.*]], align 1
66; CHECK-NEXT:    [[EQ_NULL:%.*]] = icmp eq i8 [[CHAR0]], 0
67; CHECK-NEXT:    ret i1 [[EQ_NULL]]
68;
69  %str_l = call i32 @strlen(ptr %str_p)
70  %eq_null = icmp eq i32 %str_l, 0
71  ret i1 %eq_null
72}
73
74; Check strlen(x) != 0 --> *x != 0.
75
76define i1 @test_simplify7() {
77; CHECK-LABEL: @test_simplify7(
78; CHECK-NEXT:    ret i1 true
79;
80  %hello_l = call i32 @strlen(ptr @hello)
81  %ne_hello = icmp ne i32 %hello_l, 0
82  ret i1 %ne_hello
83}
84
85define i1 @test_simplify8(ptr %str_p) {
86; CHECK-LABEL: @test_simplify8(
87; CHECK-NEXT:    [[CHAR0:%.*]] = load i8, ptr [[STR_P:%.*]], align 1
88; CHECK-NEXT:    [[NE_NULL:%.*]] = icmp ne i8 [[CHAR0]], 0
89; CHECK-NEXT:    ret i1 [[NE_NULL]]
90;
91  %str_l = call i32 @strlen(ptr %str_p)
92  %ne_null = icmp ne i32 %str_l, 0
93  ret i1 %ne_null
94}
95
96define i32 @test_simplify9(i1 %x) {
97; CHECK-LABEL: @test_simplify9(
98; CHECK-NEXT:    [[L:%.*]] = select i1 [[X:%.*]], i32 5, i32 6
99; CHECK-NEXT:    ret i32 [[L]]
100;
101  %s = select i1 %x, ptr @hello, ptr @longer
102  %l = call i32 @strlen(ptr %s)
103  ret i32 %l
104}
105
106; Check the case that should be simplified to a sub instruction.
107; strlen(@hello + x) --> 5 - x
108
109define i32 @test_simplify10_inbounds(i32 %x) {
110; CHECK-LABEL: @test_simplify10_inbounds(
111; CHECK-NEXT:    [[HELLO_L:%.*]] = sub i32 5, [[X:%.*]]
112; CHECK-NEXT:    ret i32 [[HELLO_L]]
113;
114  %hello_p = getelementptr inbounds [6 x i8], ptr @hello, i32 0, i32 %x
115  %hello_l = call i32 @strlen(ptr %hello_p)
116  ret i32 %hello_l
117}
118
119define i32 @test_simplify10_no_inbounds(i32 %x) {
120; CHECK-LABEL: @test_simplify10_no_inbounds(
121; CHECK-NEXT:    [[HELLO_L:%.*]] = sub i32 5, [[X:%.*]]
122; CHECK-NEXT:    ret i32 [[HELLO_L]]
123;
124  %hello_p = getelementptr [6 x i8], ptr @hello, i32 0, i32 %x
125  %hello_l = call i32 @strlen(ptr %hello_p)
126  ret i32 %hello_l
127}
128
129; strlen(@null_hello_mid + (x & 7)) --> 9 - (x & 7)
130
131define i32 @test_simplify11(i32 %x) {
132; CHECK-LABEL: @test_simplify11(
133; CHECK-NEXT:    [[AND:%.*]] = and i32 [[X:%.*]], 7
134; CHECK-NEXT:    [[HELLO_L:%.*]] = sub nuw nsw i32 9, [[AND]]
135; CHECK-NEXT:    ret i32 [[HELLO_L]]
136;
137  %and = and i32 %x, 7
138  %hello_p = getelementptr inbounds [13 x i8], ptr @null_hello_mid, i32 0, i32 %and
139  %hello_l = call i32 @strlen(ptr %hello_p)
140  ret i32 %hello_l
141}
142
143; Check cases that shouldn't be simplified.
144
145define i32 @test_no_simplify1() {
146; CHECK-LABEL: @test_no_simplify1(
147; CHECK-NEXT:    [[A_L:%.*]] = call i32 @strlen(ptr noundef nonnull dereferenceable(1) @a)
148; CHECK-NEXT:    ret i32 [[A_L]]
149;
150  %a_l = call i32 @strlen(ptr @a)
151  ret i32 %a_l
152}
153
154; strlen(@null_hello + x) should not be simplified to a sub instruction.
155
156define i32 @test_no_simplify2(i32 %x) {
157; CHECK-LABEL: @test_no_simplify2(
158; CHECK-NEXT:    [[HELLO_P:%.*]] = getelementptr inbounds [7 x i8], ptr @null_hello, i32 0, i32 [[X:%.*]]
159; CHECK-NEXT:    [[HELLO_L:%.*]] = call i32 @strlen(ptr noundef nonnull dereferenceable(1) [[HELLO_P]])
160; CHECK-NEXT:    ret i32 [[HELLO_L]]
161;
162  %hello_p = getelementptr inbounds [7 x i8], ptr @null_hello, i32 0, i32 %x
163  %hello_l = call i32 @strlen(ptr %hello_p)
164  ret i32 %hello_l
165}
166
167define i32 @test_no_simplify2_no_null_opt(i32 %x) #0 {
168; CHECK-LABEL: @test_no_simplify2_no_null_opt(
169; CHECK-NEXT:    [[HELLO_P:%.*]] = getelementptr inbounds [7 x i8], ptr @null_hello, i32 0, i32 [[X:%.*]]
170; CHECK-NEXT:    [[HELLO_L:%.*]] = call i32 @strlen(ptr noundef [[HELLO_P]])
171; CHECK-NEXT:    ret i32 [[HELLO_L]]
172;
173  %hello_p = getelementptr inbounds [7 x i8], ptr @null_hello, i32 0, i32 %x
174  %hello_l = call i32 @strlen(ptr %hello_p)
175  ret i32 %hello_l
176}
177
178; strlen(@null_hello_mid + (x & 15)) should not be simplified to a sub instruction.
179
180define i32 @test_no_simplify3(i32 %x) {
181; CHECK-LABEL: @test_no_simplify3(
182; CHECK-NEXT:    [[AND:%.*]] = and i32 [[X:%.*]], 15
183; CHECK-NEXT:    [[HELLO_P:%.*]] = getelementptr inbounds nuw [13 x i8], ptr @null_hello_mid, i32 0, i32 [[AND]]
184; CHECK-NEXT:    [[HELLO_L:%.*]] = call i32 @strlen(ptr noundef nonnull dereferenceable(1) [[HELLO_P]])
185; CHECK-NEXT:    ret i32 [[HELLO_L]]
186;
187  %and = and i32 %x, 15
188  %hello_p = getelementptr inbounds [13 x i8], ptr @null_hello_mid, i32 0, i32 %and
189  %hello_l = call i32 @strlen(ptr %hello_p)
190  ret i32 %hello_l
191}
192
193define i32 @test_no_simplify3_on_null_opt(i32 %x) #0 {
194; CHECK-LABEL: @test_no_simplify3_on_null_opt(
195; CHECK-NEXT:    [[AND:%.*]] = and i32 [[X:%.*]], 15
196; CHECK-NEXT:    [[HELLO_P:%.*]] = getelementptr inbounds nuw [13 x i8], ptr @null_hello_mid, i32 0, i32 [[AND]]
197; CHECK-NEXT:    [[HELLO_L:%.*]] = call i32 @strlen(ptr noundef nonnull dereferenceable(1) [[HELLO_P]])
198; CHECK-NEXT:    ret i32 [[HELLO_L]]
199;
200  %and = and i32 %x, 15
201  %hello_p = getelementptr inbounds [13 x i8], ptr @null_hello_mid, i32 0, i32 %and
202  %hello_l = call i32 @strlen(ptr %hello_p)
203  ret i32 %hello_l
204}
205
206define i32 @test1(ptr %str) {
207; CHECK-LABEL: @test1(
208; CHECK-NEXT:    [[LEN:%.*]] = tail call i32 @strlen(ptr noundef nonnull dereferenceable(1) [[STR:%.*]]) #[[ATTR1:[0-9]+]]
209; CHECK-NEXT:    ret i32 [[LEN]]
210;
211  %len = tail call i32 @strlen(ptr %str) nounwind
212  ret i32 %len
213}
214
215define i32 @test2(ptr %str) #0 {
216; CHECK-LABEL: @test2(
217; CHECK-NEXT:    [[LEN:%.*]] = tail call i32 @strlen(ptr noundef [[STR:%.*]]) #[[ATTR1]]
218; CHECK-NEXT:    ret i32 [[LEN]]
219;
220  %len = tail call i32 @strlen(ptr %str) nounwind
221  ret i32 %len
222}
223
224; Test cases for PR47149.
225define i1 @strlen0_after_write_to_first_byte_global() {
226; CHECK-LABEL: @strlen0_after_write_to_first_byte_global(
227; CHECK-NEXT:    store i8 49, ptr @a, align 16
228; CHECK-NEXT:    ret i1 false
229;
230  store i8 49, ptr @a, align 16
231  %len = tail call i32 @strlen(ptr nonnull dereferenceable(1) @a)
232  %cmp = icmp eq i32 %len, 0
233  ret i1 %cmp
234}
235
236define i1 @strlen0_after_write_to_second_byte_global() {
237; CHECK-LABEL: @strlen0_after_write_to_second_byte_global(
238; CHECK-NEXT:    store i8 49, ptr getelementptr inbounds nuw (i8, ptr @a, i32 1), align 16
239; CHECK-NEXT:    [[CHAR0:%.*]] = load i8, ptr @a, align 1
240; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8 [[CHAR0]], 0
241; CHECK-NEXT:    ret i1 [[CMP]]
242;
243  store i8 49, ptr getelementptr inbounds ([32 x i8], ptr @a, i64 0, i64 1), align 16
244  %len = tail call i32 @strlen(ptr nonnull dereferenceable(1) @a)
245  %cmp = icmp eq i32 %len, 0
246  ret i1 %cmp
247}
248
249define i1 @strlen0_after_write_to_first_byte(ptr %ptr) {
250; CHECK-LABEL: @strlen0_after_write_to_first_byte(
251; CHECK-NEXT:    store i8 49, ptr [[PTR:%.*]], align 1
252; CHECK-NEXT:    ret i1 false
253;
254  store i8 49, ptr %ptr
255  %len = tail call i32 @strlen(ptr nonnull dereferenceable(1) %ptr)
256  %cmp = icmp eq i32 %len, 0
257  ret i1 %cmp
258}
259
260define i1 @strlen0_after_write_to_second_byte(ptr %ptr) {
261; CHECK-LABEL: @strlen0_after_write_to_second_byte(
262; CHECK-NEXT:    [[GEP:%.*]] = getelementptr i8, ptr [[PTR:%.*]], i32 1
263; CHECK-NEXT:    store i8 49, ptr [[GEP]], align 1
264; CHECK-NEXT:    [[CHAR0:%.*]] = load i8, ptr [[PTR]], align 1
265; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8 [[CHAR0]], 0
266; CHECK-NEXT:    ret i1 [[CMP]]
267;
268  %gep = getelementptr i8, ptr %ptr, i64 1
269  store i8 49, ptr %gep
270  %len = tail call i32 @strlen(ptr nonnull dereferenceable(1) %ptr)
271  %cmp = icmp eq i32 %len, 0
272  ret i1 %cmp
273}
274
275attributes #0 = { null_pointer_is_valid }
276