1; RUN: opt -analyze -scalar-evolution < %s | FileCheck %s
2
3; The initial SCEV for the backedge count is
4;   (zext i2 {(trunc i32 (1 + %a1) to i2),+,1}<%b2> to i32).
5; In howFarToZero, this was further converted to an add-rec, the complexity
6; of which defeated the calculation of the backedge taken count.
7; Since such zero-extensions preserve the values being extended, strip
8; them in howFarToZero to simplify the input SCEV.
9
10; Check that the backedge taken count was actually computed:
11; CHECK: Determining loop execution counts for: @f0
12; CHECK-NEXT: Loop %b2: backedge-taken count is (-1 + (-1 * (trunc i32 %a1 to i2)))
13
14target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64"
15
16define i32 @f0(i32 %a0, i32 %a1, i32* nocapture %a2) #0 {
17b0:
18  %v0 = and i32 %a1, 3
19  %v1 = icmp eq i32 %v0, 0
20  br i1 %v1, label %b4, label %b1
21
22b1:                                               ; preds = %b0
23  %v2 = shl i32 %a0, 7
24  %v3 = add i32 %v2, -128
25  br label %b2
26
27b2:                                               ; preds = %b2, %b1
28  %v4 = phi i32 [ %a1, %b1 ], [ %v9, %b2 ]
29  %v5 = phi i32* [ %a2, %b1 ], [ %v8, %b2 ]
30  %v6 = getelementptr inbounds i32, i32* %v5, i32 0
31  store i32 %v3, i32* %v6, align 4
32  %v8 = getelementptr inbounds i32, i32* %v5, i32 1
33  %v9 = add nsw i32 %v4, 1
34  %v10 = and i32 %v9, 3
35  %v11 = icmp eq i32 %v10, 0
36  br i1 %v11, label %b3, label %b2
37
38b3:                                               ; preds = %b2
39  br label %b4
40
41b4:                                               ; preds = %b3, %b0
42  ret i32 0
43}
44
45attributes #0 = { norecurse nounwind }
46