1; RUN: opt < %s -S -loop-unroll -unroll-force-peel-count=3 -simplifycfg -instcombine | FileCheck %s
2
3; Basic loop peeling - check that we can peel-off the first 3 loop iterations
4; when explicitly requested.
5; CHECK-LABEL: @basic
6; CHECK: %[[CMP0:.*]] = icmp sgt i32 %k, 0
7; CHECK: br i1 %[[CMP0]], label %[[NEXT0:.*]], label %for.end
8; CHECK: [[NEXT0]]:
9; CHECK: store i32 0, i32* %p, align 4
10; CHECK: %[[CMP1:.*]] = icmp eq i32 %k, 1
11; CHECK: br i1 %[[CMP1]], label %for.end, label %[[NEXT1:.*]]
12; CHECK: [[NEXT1]]:
13; CHECK: %[[INC1:.*]] = getelementptr inbounds i32, i32* %p, i64 1
14; CHECK: store i32 1, i32* %[[INC1]], align 4
15; CHECK: %[[CMP2:.*]] = icmp sgt i32 %k, 2
16; CHECK: br i1 %[[CMP2]], label %[[NEXT2:.*]], label %for.end
17; CHECK: [[NEXT2]]:
18; CHECK: %[[INC2:.*]] = getelementptr inbounds i32, i32* %p, i64 2
19; CHECK: store i32 2, i32* %[[INC2]], align 4
20; CHECK: %[[CMP3:.*]] = icmp eq i32 %k, 3
21; CHECK: br i1 %[[CMP3]], label %for.end, label %[[LOOP:.*]]
22; CHECK: [[LOOP]]:
23; CHECK: %[[IV:.*]] = phi i32 [ {{.*}}, %[[LOOP]] ], [ 3, %[[NEXT2]] ]
24
25define void @basic(i32* %p, i32 %k) #0 {
26entry:
27  %cmp3 = icmp slt i32 0, %k
28  br i1 %cmp3, label %for.body.lr.ph, label %for.end
29
30for.body.lr.ph:                                   ; preds = %entry
31  br label %for.body
32
33for.body:                                         ; preds = %for.body.lr.ph, %for.body
34  %i.05 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.body ]
35  %p.addr.04 = phi i32* [ %p, %for.body.lr.ph ], [ %incdec.ptr, %for.body ]
36  %incdec.ptr = getelementptr inbounds i32, i32* %p.addr.04, i32 1
37  store i32 %i.05, i32* %p.addr.04, align 4
38  %inc = add nsw i32 %i.05, 1
39  %cmp = icmp slt i32 %inc, %k
40  br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge
41
42for.cond.for.end_crit_edge:                       ; preds = %for.body
43  br label %for.end
44
45for.end:                                          ; preds = %for.cond.for.end_crit_edge, %entry
46  ret void
47}
48
49; Make sure peeling works correctly when a value defined in a loop is used
50; in later code - we need to correctly plumb the phi depending on which
51; iteration is actually used.
52; CHECK-LABEL: @output
53; CHECK: %[[CMP0:.*]] = icmp sgt i32 %k, 0
54; CHECK: br i1 %[[CMP0]], label %[[NEXT0:.*]], label %for.end
55; CHECK: [[NEXT0]]:
56; CHECK: store i32 0, i32* %p, align 4
57; CHECK: %[[CMP1:.*]] = icmp eq i32 %k, 1
58; CHECK: br i1 %[[CMP1]], label %for.end, label %[[NEXT1:.*]]
59; CHECK: [[NEXT1]]:
60; CHECK: %[[INC1:.*]] = getelementptr inbounds i32, i32* %p, i64 1
61; CHECK: store i32 1, i32* %[[INC1]], align 4
62; CHECK: %[[CMP2:.*]] = icmp sgt i32 %k, 2
63; CHECK: br i1 %[[CMP2]], label %[[NEXT2:.*]], label %for.end
64; CHECK: [[NEXT2]]:
65; CHECK: %[[INC2:.*]] = getelementptr inbounds i32, i32* %p, i64 2
66; CHECK: store i32 2, i32* %[[INC2]], align 4
67; CHECK: %[[CMP3:.*]] = icmp eq i32 %k, 3
68; CHECK: br i1 %[[CMP3]], label %for.end, label %[[LOOP:.*]]
69; CHECK: [[LOOP]]:
70; CHECK: %[[IV:.*]] = phi i32 [ %[[IV:.*]], %[[LOOP]] ], [ 3, %[[NEXT2]] ]
71; CHECK: %ret = phi i32 [ 0, %entry ], [ 1, %[[NEXT0]] ], [ 2, %[[NEXT1]] ], [ 3, %[[NEXT2]] ], [ %[[IV]], %[[LOOP]] ]
72; CHECK: ret i32 %ret
73define i32 @output(i32* %p, i32 %k) #0 {
74entry:
75  %cmp3 = icmp slt i32 0, %k
76  br i1 %cmp3, label %for.body.lr.ph, label %for.end
77
78for.body.lr.ph:                                   ; preds = %entry
79  br label %for.body
80
81for.body:                                         ; preds = %for.body.lr.ph, %for.body
82  %i.05 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.body ]
83  %p.addr.04 = phi i32* [ %p, %for.body.lr.ph ], [ %incdec.ptr, %for.body ]
84  %incdec.ptr = getelementptr inbounds i32, i32* %p.addr.04, i32 1
85  store i32 %i.05, i32* %p.addr.04, align 4
86  %inc = add nsw i32 %i.05, 1
87  %cmp = icmp slt i32 %inc, %k
88  br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge
89
90for.cond.for.end_crit_edge:                       ; preds = %for.body
91  br label %for.end
92
93for.end:                                          ; preds = %for.cond.for.end_crit_edge, %entry
94  %ret = phi i32 [ 0, %entry], [ %inc, %for.cond.for.end_crit_edge ]
95  ret i32 %ret
96}
97