1; RUN: opt -S -O1 < %s -o %t1.ll
2; RUN: opt -S < %t1.ll -o %t2.ll
3; RUN: opt -S -simplifycfg < %t1.ll -o %t3.ll
4;; Show that there's no difference after running another simplify CFG
5; RUN: diff %t2.ll %t3.ll
6
7; Test from LoopSink pass, leaves some single-entry single-exit basic blocks.
8; After LoopSink, we get a basic block .exit.loopexit which has one entry and
9; one exit, the only instruction is a branch. Make sure it doesn't show up.
10; Make sure they disappear at -O1.
11
12@g = global i32 0, align 4
13
14define i32 @t1(i32, i32) {
15  %3 = icmp eq i32 %1, 0
16  br i1 %3, label %.exit, label %.preheader
17
18.preheader:
19  %invariant = load i32, i32* @g
20  br label %.b1
21
22.b1:
23  %iv = phi i32 [ %t7, %.b7 ], [ 0, %.preheader ]
24  %c1 = icmp sgt i32 %iv, %0
25  br i1 %c1, label %.b2, label %.b6
26
27.b2:
28  %c2 = icmp sgt i32 %iv, 1
29  br i1 %c2, label %.b3, label %.b4
30
31.b3:
32  %t3 = sub nsw i32 %invariant, %iv
33  br label %.b5
34
35.b4:
36  %t4 = add nsw i32 %invariant, %iv
37  br label %.b5
38
39.b5:
40  %p5 = phi i32 [ %t3, %.b3 ], [ %t4, %.b4 ]
41  %t5 = mul nsw i32 %p5, 5
42  br label %.b7
43
44.b6:
45  %t6 = add nsw i32 %iv, 100
46  br label %.b7
47
48.b7:
49  %p7 = phi i32 [ %t6, %.b6 ], [ %t5, %.b5 ]
50  %t7 = add nuw nsw i32 %iv, 1
51  %c7 = icmp eq i32 %t7, %p7
52  br i1 %c7, label %.b1, label %.exit
53
54.exit:
55  ret i32 10
56}
57
58