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gerrit-public.fairphone.software / toolchain / llvm-project / c88f5d3c2cbb844fce0bf3af813e768dddcc0c32 / . / llvm / test / Analysis / ScalarEvolution / shift-op.ll
blob: fe832d5676876618192a71bfa8c845c78a408b12 [file] [log] [blame]
Sanjoy Dasc88f5d32015-10-28 21:27:14 +0000[diff] [blame^]1; RUN: opt -analyze -scalar-evolution < %s | FileCheck %s
2
3define void @test0(i32 %init) {
4; CHECK-LABEL: Classifying expressions for: @test0
5; CHECK: Loop %loop: max backedge-taken count is 32
6 entry:
7 br label %loop
8
9 loop:
10 %iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
11 %iv.shift = lshr i32 %iv, 1
12 %exit.cond = icmp eq i32 %iv, 0
13 br i1 %exit.cond, label %leave, label %loop
14
15 leave:
16 ret void
17}
18
19define void @test1(i32 %init) {
20; CHECK-LABEL: Classifying expressions for: @test1
21; CHECK: Loop %loop: max backedge-taken count is 32
22 entry:
23 br label %loop
24
25 loop:
26 %iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
27 %iv.shift = shl i32 %iv, 1
28 %exit.cond = icmp eq i32 %iv, 0
29 br i1 %exit.cond, label %leave, label %loop
30
31 leave:
32 ret void
33}
34
35define void @test2(i32 %init) {
36; CHECK-LABEL: Determining loop execution counts for: @test2
37; CHECK: Loop %loop: Unpredictable max backedge-taken count.
38
39; Unpredictable because %iv could "stabilize" to either -1 or 0,
40; depending on %init.
41 entry:
42 br label %loop
43
44 loop:
45 %iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
46 %iv.shift = ashr i32 %iv, 1
47 %exit.cond = icmp eq i32 %iv, 0
48 br i1 %exit.cond, label %leave, label %loop
49
50 leave:
51 ret void
52}
53
54define void @test3(i32* %init.ptr) {
55; CHECK-LABEL: Determining loop execution counts for: @test3
56; CHECK: Loop %loop: max backedge-taken count is 32
57 entry:
58 %init = load i32, i32* %init.ptr, !range !0
59 br label %loop
60
61 loop:
62 %iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
63 %iv.shift = ashr i32 %iv, 1
64 %exit.cond = icmp eq i32 %iv, 0
65 br i1 %exit.cond, label %leave, label %loop
66
67 leave:
68 ret void
69}
70
71define void @test4(i32* %init.ptr) {
72; CHECK-LABEL: Classifying expressions for: @test4
73; CHECK-LABEL: Loop %loop: max backedge-taken count is 32
74 entry:
75 %init = load i32, i32* %init.ptr, !range !1
76 br label %loop
77
78 loop:
79 %iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
80 %iv.shift = ashr i32 %iv, 1
81 %exit.cond = icmp eq i32 %iv, -1
82 br i1 %exit.cond, label %leave, label %loop
83
84 leave:
85 ret void
86}
87
88define void @test5(i32* %init.ptr) {
89; CHECK-LABEL: Determining loop execution counts for: @test5
90; CHECK: Loop %loop: Unpredictable max backedge-taken count.
91
92; %iv will "stabilize" to -1, so this is an infinite loop
93 entry:
94 %init = load i32, i32* %init.ptr, !range !1
95 br label %loop
96
97 loop:
98 %iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
99 %iv.shift = ashr i32 %iv, 1
100 %exit.cond = icmp eq i32 %iv, 0
101 br i1 %exit.cond, label %leave, label %loop
102
103 leave:
104 ret void
105}
106
107define void @test6(i32 %init, i32 %shift.amt) {
108; CHECK-LABEL: Determining loop execution counts for: @test6
109; CHECK: Loop %loop: Unpredictable max backedge-taken count.
110
111; Potentially infinite loop, since %shift.amt could be 0
112 entry:
113 br label %loop
114
115 loop:
116 %iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
117 %iv.shift = lshr i32 %iv, %shift.amt
118 %exit.cond = icmp eq i32 %iv, 0
119 br i1 %exit.cond, label %leave, label %loop
120
121 leave:
122 ret void
123}
124
125define void @test7(i32 %init) {
126; CHECK-LABEL: Classifying expressions for: @test7
127; CHECK: Loop %loop: max backedge-taken count is 32
128
129 entry:
130 br label %loop
131
132 loop:
133 %iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
134 %iv.shift = lshr i32 %iv, 1
135 %exit.cond = icmp eq i32 %iv.shift, 0
136 br i1 %exit.cond, label %leave, label %loop
137
138 leave:
139 ret void
140}
141
142define void @test8(i32 %init) {
143; CHECK-LABEL: Classifying expressions for: @test8
144; CHECK: Loop %loop: Unpredictable max backedge-taken count.
145
146; In this test case, %iv.test stabilizes to 127, not -1, so the loop
147; is infinite.
148
149 entry:
150 br label %loop
151
152 loop:
153 %iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
154 %iv.shift = ashr i32 %iv, 1
155 %iv.test = lshr i32 %iv, 1
156 %exit.cond = icmp eq i32 %iv.test, -1
157 br i1 %exit.cond, label %leave, label %loop
158
159 leave:
160 ret void
161}
162
163!0 = !{i32 0, i32 50000}
164!1 = !{i32 -5000, i32 -1}