1; RUN: opt < %s -S -loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=10 -unroll-max-percent-threshold-boost=200 | FileCheck %s
2; RUN: opt < %s -S -passes='require<opt-remark-emit>,loop(loop-unroll-full)' -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=10 -unroll-max-percent-threshold-boost=200 | FileCheck %s
3target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
4
5@unknown_global = internal unnamed_addr global [9 x i32] [i32 0, i32 -1, i32 0, i32 -1, i32 5, i32 -1, i32 0, i32 -1, i32 0], align 16
6@weak_constant = weak unnamed_addr constant [9 x i32] [i32 0, i32 -1, i32 0, i32 -1, i32 5, i32 -1, i32 0, i32 -1, i32 0], align 16
7
8; Though @unknown_global is initialized with constant values, we can't consider
9; it as a constant, so we shouldn't unroll the loop.
10; CHECK-LABEL: @foo
11; CHECK: %array_const_idx = getelementptr inbounds [9 x i32], [9 x i32]* @unknown_global, i64 0, i64 %iv
12define i32 @foo(i32* noalias nocapture readonly %src) {
13entry:
14  br label %loop
15
16loop:                                                ; preds = %loop, %entry
17  %iv = phi i64 [ 0, %entry ], [ %inc, %loop ]
18  %r  = phi i32 [ 0, %entry ], [ %add, %loop ]
19  %arrayidx = getelementptr inbounds i32, i32* %src, i64 %iv
20  %src_element = load i32, i32* %arrayidx, align 4
21  %array_const_idx = getelementptr inbounds [9 x i32], [9 x i32]* @unknown_global, i64 0, i64 %iv
22  %const_array_element = load i32, i32* %array_const_idx, align 4
23  %mul = mul nsw i32 %src_element, %const_array_element
24  %add = add nsw i32 %mul, %r
25  %inc = add nuw nsw i64 %iv, 1
26  %exitcond86.i = icmp eq i64 %inc, 9
27  br i1 %exitcond86.i, label %loop.end, label %loop
28
29loop.end:                                            ; preds = %loop
30  %r.lcssa = phi i32 [ %r, %loop ]
31  ret i32 %r.lcssa
32}
33
34; Similarly, we can't consider 'weak' symbols as a known constant value, so we
35; shouldn't unroll the loop.
36; CHECK-LABEL: @foo2
37; CHECK: %array_const_idx = getelementptr inbounds [9 x i32], [9 x i32]* @weak_constant, i64 0, i64 %iv
38define i32 @foo2(i32* noalias nocapture readonly %src) {
39entry:
40  br label %loop
41
42loop:                                                ; preds = %loop, %entry
43  %iv = phi i64 [ 0, %entry ], [ %inc, %loop ]
44  %r  = phi i32 [ 0, %entry ], [ %add, %loop ]
45  %arrayidx = getelementptr inbounds i32, i32* %src, i64 %iv
46  %src_element = load i32, i32* %arrayidx, align 4
47  %array_const_idx = getelementptr inbounds [9 x i32], [9 x i32]* @weak_constant, i64 0, i64 %iv
48  %const_array_element = load i32, i32* %array_const_idx, align 4
49  %mul = mul nsw i32 %src_element, %const_array_element
50  %add = add nsw i32 %mul, %r
51  %inc = add nuw nsw i64 %iv, 1
52  %exitcond86.i = icmp eq i64 %inc, 9
53  br i1 %exitcond86.i, label %loop.end, label %loop
54
55loop.end:                                            ; preds = %loop
56  %r.lcssa = phi i32 [ %r, %loop ]
57  ret i32 %r.lcssa
58}
59
60; In this case the loaded value is used only to control branch.
61; If we missed that, we could've thought that it's unused and unrolling would
62; clean up almost entire loop. Make sure that we do not unroll such loop.
63; CHECK-LABEL: @foo3
64; CHECK: br i1 %exitcond, label %loop.end, label %loop.header
65define i32 @foo3(i32* noalias nocapture readonly %src) {
66entry:
67  br label %loop.header
68
69loop.header:
70  %iv = phi i64 [ 0, %entry ], [ %inc, %loop.latch ]
71  %r1  = phi i32 [ 0, %entry ], [ %r3, %loop.latch ]
72  %arrayidx = getelementptr inbounds i32, i32* %src, i64 %iv
73  %src_element = load i32, i32* %arrayidx, align 4
74  %cmp = icmp eq i32 0, %src_element
75  br i1 %cmp, label %loop.if, label %loop.latch
76
77loop.if:
78  %r2 = add i32 %r1, 1
79  br label %loop.latch
80
81loop.latch:
82  %r3 = phi i32 [%r1, %loop.header], [%r2, %loop.if]
83  %inc = add nuw nsw i64 %iv, 1
84  %exitcond = icmp eq i64 %inc, 9
85  br i1 %exitcond, label %loop.end, label %loop.header
86
87loop.end:
88  %r.lcssa = phi i32 [ %r3, %loop.latch ]
89  ret i32 %r.lcssa
90}
91