1; RUN: opt -analyze -scalar-evolution < %s | FileCheck %s
2
3; An example run where SCEV(%postinc)->getStart() may overflow:
4;
5; %start = INT_SMAX
6; %low.limit = INT_SMIN
7; %high.limit = < not used >
8;
9; >> entry:
10;  %postinc.start = INT_SMIN
11;
12; >> loop:
13;  %idx = %start
14;  %postinc = INT_SMIN
15;  %postinc.inc = INT_SMIN + 1
16;  %postinc.sext = sext(INT_SMIN) = i64 INT32_SMIN
17;  %break.early = INT_SMIN `slt` INT_SMIN = false
18;  br i1 false, ___,  %early.exit
19;
20; >> early.exit:
21;  ret i64 INT32_SMIN
22
23
24define i64 @bad.0(i32 %start, i32 %low.limit, i32 %high.limit) {
25; CHECK-LABEL: Classifying expressions for: @bad.0
26 entry:
27  %postinc.start = add i32 %start, 1
28  br label %loop
29
30 loop:
31  %idx = phi i32 [ %start, %entry ], [ %idx.inc, %continue ]
32  %postinc = phi i32 [ %postinc.start, %entry ], [ %postinc.inc, %continue ]
33  %postinc.inc = add nsw i32 %postinc, 1
34  %postinc.sext = sext i32 %postinc to i64
35; CHECK:  %postinc.sext = sext i32 %postinc to i64
36; CHECK-NEXT:  -->  {(sext i32 (1 + %start) to i64),+,1}<nsw><%loop>
37  %break.early = icmp slt i32 %postinc, %low.limit
38  br i1 %break.early, label %continue, label %early.exit
39
40 continue:
41  %idx.inc = add nsw i32 %idx, 1
42  %cmp = icmp slt i32 %idx.inc, %high.limit
43  br i1 %cmp, label %loop, label %exit
44
45 exit:
46  ret i64 0
47
48 early.exit:
49  ret i64 %postinc.sext
50}
51
52define i64 @bad.1(i32 %start, i32 %low.limit, i32 %high.limit, i1* %unknown) {
53; CHECK-LABEL: Classifying expressions for: @bad.1
54 entry:
55  %postinc.start = add i32 %start, 1
56  br label %loop
57
58 loop:
59  %idx = phi i32 [ %start, %entry ], [ %idx.inc, %continue ], [ %idx.inc, %continue.1 ]
60  %postinc = phi i32 [ %postinc.start, %entry ], [ %postinc.inc, %continue ], [ %postinc.inc, %continue.1 ]
61  %postinc.inc = add nsw i32 %postinc, 1
62  %postinc.sext = sext i32 %postinc to i64
63; CHECK:  %postinc.sext = sext i32 %postinc to i64
64; CHECK-NEXT:  -->  {(sext i32 (1 + %start) to i64),+,1}<nsw><%loop>
65  %break.early = icmp slt i32 %postinc, %low.limit
66  br i1 %break.early, label %continue.1, label %early.exit
67
68 continue.1:
69  %cond = load volatile i1, i1* %unknown
70  %idx.inc = add nsw i32 %idx, 1
71  br i1 %cond, label %loop, label %continue
72
73 continue:
74  %cmp = icmp slt i32 %idx.inc, %high.limit
75  br i1 %cmp, label %loop, label %exit
76
77 exit:
78  ret i64 0
79
80 early.exit:
81  ret i64 %postinc.sext
82}
83