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
194
195
196
197
198
199
200
201
202
203
204
205
|
; RUN: opt < %s -gvn -o /dev/null -pass-remarks-output=%t -S
; RUN: cat %t | FileCheck %s
; ModuleID = 'bugpoint-reduced-simplified.bc'
source_filename = "gvn-test.c"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; CHECK: --- !Missed
; CHECK-NEXT: Pass: gvn
; CHECK-NEXT: Name: LoadClobbered
; CHECK-NEXT: Function: nonDominating1
; CHECK-NEXT: Args:
; CHECK-NEXT: - String: 'load of type '
; CHECK-NEXT: - Type: i32
; CHECK-NEXT: - String: ' not eliminated'
; CHECK-NEXT: - String: ' in favor of '
; CHECK-NEXT: - OtherAccess: store
; CHECK-NEXT: - String: ' because it is clobbered by '
; CHECK-NEXT: - ClobberedBy: call
; CHECK-NEXT: ...
; Confirm that the partial redundancy being clobbered by the call to
; clobberingFunc() between store and load is identified.
define dso_local void @nonDominating1(i32* %a, i1 %cond, i32 %b) local_unnamed_addr #0 {
entry:
br i1 %cond, label %if.then, label %if.end
if.then: ; preds = %entry
store i32 %b, i32* %a, align 4
br label %if.end
if.end: ; preds = %if.then, %entry
tail call void @clobberingFunc() #1
%0 = load i32, i32* %a, align 4
%mul2 = shl nsw i32 %0, 1
store i32 %mul2, i32* %a, align 4
ret void
}
declare dso_local void @clobberingFunc() local_unnamed_addr #0
; CHECK: --- !Missed
; CHECK-NEXT: Pass: gvn
; CHECK-NEXT: Name: LoadClobbered
; CHECK-NEXT: DebugLoc: { File: '/tmp/s.c', Line: 3, Column: 3 }
; CHECK-NEXT: Function: nonDominating2
; CHECK-NEXT: Args:
; CHECK-NEXT: - String: 'load of type '
; CHECK-NEXT: - Type: i32
; CHECK-NEXT: - String: ' not eliminated'
; CHECK-NEXT: - String: ' in favor of '
; CHECK-NEXT: - OtherAccess: load
; CHECK-NEXT: DebugLoc: { File: '/tmp/s.c', Line: 1, Column: 1 }
; CHECK-NEXT: - String: ' because it is clobbered by '
; CHECK-NEXT: - ClobberedBy: call
; CHECK-NEXT: DebugLoc: { File: '/tmp/s.c', Line: 2, Column: 2 }
; CHECK-NEXT: ...
; CHECK: --- !Missed
; CHECK-NEXT: Pass: gvn
; CHECK-NEXT: Name: LoadClobbered
; CHECK-NEXT: DebugLoc: { File: '/tmp/s.c', Line: 5, Column: 5 }
; CHECK-NEXT: Function: nonDominating2
; CHECK-NEXT: Args:
; CHECK-NEXT: - String: 'load of type '
; CHECK-NEXT: - Type: i32
; CHECK-NEXT: - String: ' not eliminated'
; CHECK-NEXT: - String: ' in favor of '
; CHECK-NEXT: - OtherAccess: load
; CHECK-NEXT: DebugLoc: { File: '/tmp/s.c', Line: 3, Column: 3 }
; CHECK-NEXT: - String: ' because it is clobbered by '
; CHECK-NEXT: - ClobberedBy: call
; CHECK-NEXT: DebugLoc: { File: '/tmp/s.c', Line: 4, Column: 4 }
; CHECK-NEXT: ...
; More complex version of nonDominating1(), this time with loads. The values
; already loaded into %0 and %1 cannot replace %2 due to clobbering calls.
; %1 is not clobbered by the first call however, and %0 is irrelevant for the
; second one since %1 is more recently available.
define dso_local void @nonDominating2(i32* %a, i1 %cond) local_unnamed_addr #0 {
entry:
br i1 %cond, label %if.then, label %if.end5
if.then: ; preds = %entry
%0 = load i32, i32* %a, align 4, !dbg !14
%mul = mul nsw i32 %0, 10
tail call void @clobberingFunc() #1, !dbg !15
%1 = load i32, i32* %a, align 4, !dbg !16
%mul3 = mul nsw i32 %1, 5
tail call void @clobberingFunc() #1, !dbg !17
br label %if.end5
if.end5: ; preds = %if.then, %entry
%2 = load i32, i32* %a, align 4, !dbg !18
%mul9 = shl nsw i32 %2, 1
store i32 %mul9, i32* %a, align 4
ret void
}
; CHECK: --- !Missed
; CHECK-NEXT: Pass: gvn
; CHECK-NEXT: Name: LoadClobbered
; CHECK-NEXT: Function: nonDominating3
; CHECK-NEXT: Args:
; CHECK-NEXT: - String: 'load of type '
; CHECK-NEXT: - Type: i32
; CHECK-NEXT: - String: ' not eliminated'
; CHECK-NEXT: - String: ' because it is clobbered by '
; CHECK-NEXT: - ClobberedBy: call
; CHECK-NEXT: ...
; The two stores are both partially available at %0 (were it not for the
; clobbering call), however neither is strictly more recent than the other, so
; no attempt is made to identify what value could have potentially been reused
; otherwise. Just report that the load cannot be eliminated.
define dso_local void @nonDominating3(i32* %a, i32 %b, i32 %c, i1 %cond) local_unnamed_addr #0 {
entry:
br i1 %cond, label %if.end5.sink.split, label %if.else
if.else: ; preds = %entry
store i32 %b, i32* %a, align 4
br label %if.end5
if.end5.sink.split: ; preds = %entry
store i32 %c, i32* %a, align 4
br label %if.end5
if.end5: ; preds = %if.end5.sink.split, %if.else
tail call void @clobberingFunc() #1
%0 = load i32, i32* %a, align 4
%mul7 = shl nsw i32 %0, 1
ret void
}
; CHECK: --- !Missed
; CHECK-NEXT: Pass: gvn
; CHECK-NEXT: Name: LoadClobbered
; CHECK-NEXT: Function: nonDominating4
; CHECK-NEXT: Args:
; CHECK-NEXT: - String: 'load of type '
; CHECK-NEXT: - Type: i32
; CHECK-NEXT: - String: ' not eliminated'
; CHECK-NEXT: - String: ' in favor of '
; CHECK-NEXT: - OtherAccess: store
; CHECK-NEXT: - String: ' because it is clobbered by '
; CHECK-NEXT: - ClobberedBy: call
; CHECK-NEXT: ...
; Make sure isPotentiallyReachable() is not called for an instruction
; outside the current function, as it will cause a crash.
define dso_local void @nonDominating4(i1 %cond, i32 %b) local_unnamed_addr #0 {
entry:
br i1 %cond, label %if.then, label %if.end
if.then: ; preds = %entry
store i32 %b, i32* @g, align 4
br label %if.end
if.end: ; preds = %if.then, %entry
tail call void @clobberingFunc() #1
%0 = load i32, i32* @g, align 4
%mul2 = shl nsw i32 %0, 1
store i32 %mul2, i32* @g, align 4
ret void
}
@g = external global i32
define dso_local void @globalUser(i32 %b) local_unnamed_addr #0 {
entry:
store i32 %b, i32* @g, align 4
ret void
}
attributes #0 = { "use-soft-float"="false" }
attributes #1 = { nounwind }
!llvm.ident = !{!0}
!llvm.dbg.cu = !{!1}
!llvm.module.flags = !{!4, !5, !6}
!0 = !{!"clang version 10.0.0 (git@github.com:llvm/llvm-project.git a2f6ae9abffcba260c22bb235879f0576bf3b783)"}
!1 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, producer: "clang version 4.0.0 (trunk 282540) (llvm/trunk 282542)", isOptimized: true, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !3)
!2 = !DIFile(filename: "/tmp/s.c", directory: "/tmp")
!3 = !{}
!4 = !{i32 2, !"Dwarf Version", i32 4}
!5 = !{i32 2, !"Debug Info Version", i32 3}
!6 = !{i32 1, !"PIC Level", i32 2}
!8 = distinct !DISubprogram(name: "nonDominating2", scope: !2, file: !2, line: 1, type: !9, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !1, retainedNodes: !3)
!9 = !DISubroutineType(types: !10)
!10 = !{null, !11, !12, !12, !13}
!11 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !12, size: 64)
!12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!13 = !DIBasicType(name: "_Bool", size: 8, encoding: DW_ATE_boolean)
!14 = !DILocation(line: 1, column: 1, scope: !8)
!15 = !DILocation(line: 2, column: 2, scope: !8)
!16 = !DILocation(line: 3, column: 3, scope: !8)
!17 = !DILocation(line: 4, column: 4, scope: !8)
!18 = !DILocation(line: 5, column: 5, scope: !8)
|
