1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
|
; RUN: opt < %s -passes=indvars -S | FileCheck %s
; These tests ensure that we can compute the trip count of various forms of
; loops. If the trip count of the loop is computable, then we will know what
; the exit value of the loop will be for some value, allowing us to substitute
; it directly into users outside of the loop, making the loop dead.
; CHECK-LABEL: @linear_setne(
; CHECK: ret i32 100
define i32 @linear_setne() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 0, %entry ], [ %i.next, %loop ] ; <i32> [#uses=3]
%i.next = add i32 %i, 1 ; <i32> [#uses=1]
%c = icmp ne i32 %i, 100 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
ret i32 %i
}
; CHECK-LABEL: @linear_setne_2(
; CHECK: ret i32 100
define i32 @linear_setne_2() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 0, %entry ], [ %i.next, %loop ] ; <i32> [#uses=3]
%i.next = add i32 %i, 2 ; <i32> [#uses=1]
%c = icmp ne i32 %i, 100 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
ret i32 %i
}
; CHECK-LABEL: @linear_setne_overflow(
; CHECK: ret i32 0
define i32 @linear_setne_overflow() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 1024, %entry ], [ %i.next, %loop ] ; <i32> [#uses=3]
%i.next = add i32 %i, 1024 ; <i32> [#uses=1]
%c = icmp ne i32 %i, 0 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
ret i32 %i
}
; CHECK-LABEL: @linear_setlt(
; CHECK: ret i32 100
define i32 @linear_setlt() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 0, %entry ], [ %i.next, %loop ] ; <i32> [#uses=3]
%i.next = add i32 %i, 1 ; <i32> [#uses=1]
%c = icmp slt i32 %i, 100 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
ret i32 %i
}
; CHECK-LABEL: @quadratic_setlt(
; CHECK: ret i32 34
define i32 @quadratic_setlt() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 7, %entry ], [ %i.next, %loop ] ; <i32> [#uses=4]
%i.next = add i32 %i, 3 ; <i32> [#uses=1]
%i2 = mul i32 %i, %i ; <i32> [#uses=1]
%c = icmp slt i32 %i2, 1000 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
ret i32 %i
}
; CHECK-LABEL: @chained(
; CHECK: ret i32 200
define i32 @chained() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 0, %entry ], [ %i.next, %loop ] ; <i32> [#uses=3]
%i.next = add i32 %i, 1 ; <i32> [#uses=1]
%c = icmp ne i32 %i, 100 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
br label %loop2
loop2: ; preds = %loop2, %loopexit
%j = phi i32 [ %i, %loopexit ], [ %j.next, %loop2 ] ; <i32> [#uses=3]
%j.next = add i32 %j, 1 ; <i32> [#uses=1]
%c2 = icmp ne i32 %j, 200 ; <i1> [#uses=1]
br i1 %c2, label %loop2, label %loopexit2
loopexit2: ; preds = %loop2
ret i32 %j
}
; CHECK-LABEL: @chained4(
; CHECK: ret i32 400
define i32 @chained4() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 0, %entry ], [ %i.next, %loop ] ; <i32> [#uses=3]
%i.next = add i32 %i, 1 ; <i32> [#uses=1]
%c = icmp ne i32 %i.next, 100 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
br label %loop2
loop2: ; preds = %loop2, %loopexit
%j = phi i32 [ %i.next, %loopexit ], [ %j.next, %loop2 ] ; <i32> [#uses=3]
%j.next = add i32 %j, 1 ; <i32> [#uses=1]
%c2 = icmp ne i32 %j.next, 200 ; <i1> [#uses=1]
br i1 %c2, label %loop2, label %loopexit2
loopexit2: ; preds = %loop
br label %loop8
loop8: ; preds = %loop2, %loopexit
%k = phi i32 [ %j.next, %loopexit2 ], [ %k.next, %loop8 ] ; <i32> [#uses=3]
%k.next = add i32 %k, 1 ; <i32> [#uses=1]
%c8 = icmp ne i32 %k.next, 300 ; <i1> [#uses=1]
br i1 %c8, label %loop8, label %loopexit8
loopexit8: ; preds = %loop2
br label %loop9
loop9: ; preds = %loop2, %loopexit
%l = phi i32 [ %k.next, %loopexit8 ], [ %l.next, %loop9 ] ; <i32> [#uses=3]
%l.next = add i32 %l, 1 ; <i32> [#uses=1]
%c9 = icmp ne i32 %l.next, 400 ; <i1> [#uses=1]
br i1 %c9, label %loop9, label %loopexit9
loopexit9: ; preds = %loop2
ret i32 %l.next
}
; PR18449. Check that the early exit is reduced to never taken.
;
; CHECK-LABEL: @twoexit
; CHECK-LABEL: loop:
; CHECK: phi
; CHECK: br i1 false
; CHECK: br
; CHECK: ret
define void @twoexit() {
"function top level":
br label %loop
loop: ; preds = %body, %"function top level"
%0 = phi i64 [ 0, %"function top level" ], [ %2, %body ]
%1 = icmp ugt i64 %0, 2
br i1 %1, label %fail, label %body
fail: ; preds = %loop
tail call void @bounds_fail()
unreachable
body: ; preds = %loop
%2 = add i64 %0, 1
%3 = icmp slt i64 %2, 3
br i1 %3, label %loop, label %out
out: ; preds = %body
ret void
}
declare void @bounds_fail()
|
