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