1; RUN: opt -jump-threading -S %s | FileCheck %s
2
3; Check that we thread arg2neg -> checkpos -> end.
4;
5; LazyValueInfo would previously fail to analyze the value of %arg in arg2neg
6; because its predecessing blocks (checkneg) hadn't been processed yet (PR21238)
7
8; CHECK-LABEL: @test_jump_threading
9; CHECK: arg2neg:
10; CHECK-NEXT: br i1 %arg1, label %end, label %checkpos.thread
11; CHECK: checkpos.thread:
12; CHECK-NEXT: br label %end
13
14define i32 @test_jump_threading(i1 %arg1, i32 %arg2) {
15checkneg:
16  %cmp = icmp slt i32 %arg2, 0
17  br i1 %cmp, label %arg2neg, label %checkpos
18
19arg2neg:
20  br i1 %arg1, label %end, label %checkpos
21
22checkpos:
23  %cmp2 = icmp sgt i32 %arg2, 0
24  br i1 %cmp2, label %arg2pos, label %end
25
26arg2pos:
27  br label %end
28
29end:
30  %0 = phi i32 [ 1, %arg2neg ], [ 2, %checkpos ], [ 3, %arg2pos ]
31  ret i32 %0
32}
33
34
35; arg2neg has an edge back to itself. If LazyValueInfo is not careful when
36; visiting predecessors, it could get into an infinite loop.
37
38; CHECK-LABEL: test_infinite_loop
39
40define i32 @test_infinite_loop(i1 %arg1, i32 %arg2) {
41checkneg:
42  %cmp = icmp slt i32 %arg2, 0
43  br i1 %cmp, label %arg2neg, label %checkpos
44
45arg2neg:
46  br i1 %arg1, label %arg2neg, label %checkpos
47
48checkpos:
49  %cmp2 = icmp sgt i32 %arg2, 0
50  br i1 %cmp2, label %arg2pos, label %end
51
52arg2pos:
53  br label %end
54
55end:
56  %0 = phi i32 [ 2, %checkpos ], [ 3, %arg2pos ]
57  ret i32 %0
58}
59