xref: /llvm-project/llvm/test/Transforms/InstCombine/memcmp-8.ll (revision 10f315dc9c96ec2413881ab55a285e35d80def88)
1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
2; RUN: opt < %s -passes=instcombine -S | FileCheck %s
3;
4; Verify that the result of memrchr calls with past-the-end pointers used
5; don't cause trouble and are optimally folded.
6
7declare i32 @memcmp(ptr, ptr, i64)
8
9
10@a5 = constant [5 x i8] c"12345";
11
12
13; Fold memcmp(a5, a5 + 5, n) to 0 on the assumption that n is 0 otherwise
14; the call would be undefined.
15
16define i32 @fold_memcmp_a5_a5p5_n(i64 %n) {
17; CHECK-LABEL: @fold_memcmp_a5_a5p5_n(
18; CHECK-NEXT:    ret i32 0
19;
20  %pa5_p5 = getelementptr [5 x i8], ptr @a5, i32 0, i32 5
21  %cmp = call i32 @memcmp(ptr @a5, ptr %pa5_p5, i64 %n)
22  ret i32 %cmp
23}
24
25
26; Same as above but for memcmp(a5 + 5, a5 + 5, n).
27
28define i32 @fold_memcmp_a5p5_a5p5_n(i64 %n) {
29; CHECK-LABEL: @fold_memcmp_a5p5_a5p5_n(
30; CHECK-NEXT:    ret i32 0
31;
32  %pa5_p5 = getelementptr [5 x i8], ptr @a5, i32 0, i32 5
33  %qa5_p5 = getelementptr [5 x i8], ptr @a5, i32 0, i32 5
34  %cmp = call i32 @memcmp(ptr %pa5_p5, ptr %qa5_p5, i64 %n)
35  ret i32 %cmp
36}
37
38
39; TODO: Likewise, fold memcmp(a5 + i, a5 + 5, n) to 0 on same basis.
40
41define i32 @fold_memcmp_a5pi_a5p5_n(i32 %i, i64 %n) {
42; CHECK-LABEL: @fold_memcmp_a5pi_a5p5_n(
43; CHECK-NEXT:    [[TMP1:%.*]] = sext i32 [[I:%.*]] to i64
44; CHECK-NEXT:    [[PA5_PI:%.*]] = getelementptr [5 x i8], ptr @a5, i64 0, i64 [[TMP1]]
45; CHECK-NEXT:    [[CMP:%.*]] = call i32 @memcmp(ptr [[PA5_PI]], ptr nonnull getelementptr inbounds nuw (i8, ptr @a5, i64 5), i64 [[N:%.*]])
46; CHECK-NEXT:    ret i32 [[CMP]]
47;
48  %pa5_pi = getelementptr [5 x i8], ptr @a5, i32 0, i32 %i
49  %pa5_p5 = getelementptr [5 x i8], ptr @a5, i32 0, i32 5
50  %cmp = call i32 @memcmp(ptr %pa5_pi, ptr %pa5_p5, i64 %n)
51  ret i32 %cmp
52}
53