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
| ; RUN: opt -S -licm < %s | FileCheck %s
; RUN: opt -passes='require<aa>,require<targetir>,require<scalar-evolution>,require<opt-remark-emit>,loop(licm)' -S %s | FileCheck %s
; UDiv is safe to speculate if the denominator is known non-zero.
; CHECK-LABEL: @safe_udiv(
; CHECK: %div = udiv i64 %x, 2
; CHECK-NEXT: br label %for.body
define void @safe_udiv(i64 %x, i64 %m, i64 %n, i32* %p, i64* %q) nounwind {
entry:
br label %for.body
for.body: ; preds = %entry, %for.inc
%i.02 = phi i64 [ %inc, %for.inc ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32, i32* %p, i64 %i.02
%0 = load i32, i32* %arrayidx, align 4
%tobool = icmp eq i32 %0, 0
br i1 %tobool, label %for.inc, label %if.then
if.then: ; preds = %for.body
%div = udiv i64 %x, 2
%arrayidx1 = getelementptr inbounds i64, i64* %q, i64 %i.02
store i64 %div, i64* %arrayidx1, align 8
br label %for.inc
for.inc: ; preds = %if.then, %for.body
%inc = add i64 %i.02, 1
%cmp = icmp slt i64 %inc, %n
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.inc, %entry
ret void
}
; UDiv is unsafe to speculate if the denominator is not known non-zero.
; CHECK-LABEL: @unsafe_udiv(
; CHECK-NOT: udiv
; CHECK: for.body:
define void @unsafe_udiv(i64 %x, i64 %m, i64 %n, i32* %p, i64* %q) nounwind {
entry:
br label %for.body
for.body: ; preds = %entry, %for.inc
%i.02 = phi i64 [ %inc, %for.inc ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32, i32* %p, i64 %i.02
%0 = load i32, i32* %arrayidx, align 4
%tobool = icmp eq i32 %0, 0
br i1 %tobool, label %for.inc, label %if.then
if.then: ; preds = %for.body
%div = udiv i64 %x, %m
%arrayidx1 = getelementptr inbounds i64, i64* %q, i64 %i.02
store i64 %div, i64* %arrayidx1, align 8
br label %for.inc
for.inc: ; preds = %if.then, %for.body
%inc = add i64 %i.02, 1
%cmp = icmp slt i64 %inc, %n
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.inc, %entry
ret void
}
; SDiv is safe to speculate if the denominator is known non-zero and
; known to have at least one zero bit.
; CHECK-LABEL: @safe_sdiv(
; CHECK: %div = sdiv i64 %x, 2
; CHECK-NEXT: br label %for.body
define void @safe_sdiv(i64 %x, i64 %m, i64 %n, i32* %p, i64* %q) nounwind {
entry:
%and = and i64 %m, -3
br label %for.body
for.body: ; preds = %entry, %for.inc
%i.02 = phi i64 [ %inc, %for.inc ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32, i32* %p, i64 %i.02
%0 = load i32, i32* %arrayidx, align 4
%tobool = icmp eq i32 %0, 0
br i1 %tobool, label %for.inc, label %if.then
if.then: ; preds = %for.body
%div = sdiv i64 %x, 2
%arrayidx1 = getelementptr inbounds i64, i64* %q, i64 %i.02
store i64 %div, i64* %arrayidx1, align 8
br label %for.inc
for.inc: ; preds = %if.then, %for.body
%inc = add i64 %i.02, 1
%cmp = icmp slt i64 %inc, %n
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.inc, %entry
ret void
}
; SDiv is unsafe to speculate if the denominator is not known non-zero.
; CHECK-LABEL: @unsafe_sdiv_a(
; CHECK-NOT: sdiv
; CHECK: for.body:
define void @unsafe_sdiv_a(i64 %x, i64 %m, i64 %n, i32* %p, i64* %q) nounwind {
entry:
%or = or i64 %m, 1
br label %for.body
for.body: ; preds = %entry, %for.inc
%i.02 = phi i64 [ %inc, %for.inc ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32, i32* %p, i64 %i.02
%0 = load i32, i32* %arrayidx, align 4
%tobool = icmp eq i32 %0, 0
br i1 %tobool, label %for.inc, label %if.then
if.then: ; preds = %for.body
%div = sdiv i64 %x, %or
%arrayidx1 = getelementptr inbounds i64, i64* %q, i64 %i.02
store i64 %div, i64* %arrayidx1, align 8
br label %for.inc
for.inc: ; preds = %if.then, %for.body
%inc = add i64 %i.02, 1
%cmp = icmp slt i64 %inc, %n
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.inc, %entry
ret void
}
; SDiv is unsafe to speculate if the denominator is not known to have a zero bit.
; CHECK-LABEL: @unsafe_sdiv_b(
; CHECK-NOT: sdiv
; CHECK: for.body:
define void @unsafe_sdiv_b(i64 %x, i64 %m, i64 %n, i32* %p, i64* %q) nounwind {
entry:
%and = and i64 %m, -3
br label %for.body
for.body: ; preds = %entry, %for.inc
%i.02 = phi i64 [ %inc, %for.inc ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32, i32* %p, i64 %i.02
%0 = load i32, i32* %arrayidx, align 4
%tobool = icmp eq i32 %0, 0
br i1 %tobool, label %for.inc, label %if.then
if.then: ; preds = %for.body
%div = sdiv i64 %x, %and
%arrayidx1 = getelementptr inbounds i64, i64* %q, i64 %i.02
store i64 %div, i64* %arrayidx1, align 8
br label %for.inc
for.inc: ; preds = %if.then, %for.body
%inc = add i64 %i.02, 1
%cmp = icmp slt i64 %inc, %n
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.inc, %entry
ret void
}
; SDiv is unsafe to speculate inside an infinite loop.
define void @unsafe_sdiv_c(i64 %a, i64 %b, i64* %p) {
entry:
; CHECK: entry:
; CHECK-NOT: sdiv
; CHECK: br label %for.body
br label %for.body
for.body:
%c = icmp eq i64 %b, 0
br i1 %c, label %backedge, label %if.then
if.then:
%d = sdiv i64 %a, %b
store i64 %d, i64* %p
br label %backedge
backedge:
br label %for.body
}
|