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
| ; RUN: opt -S -o - -basicaa -domtree -gvn %s | FileCheck %s
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
%struct.S1 = type { i32, i32 }
@a2 = common global i32* null, align 8
@a = common global i32* null, align 8
@s1 = common global %struct.S1 zeroinitializer, align 8
; Check that GVN doesn't determine %2 is partially redundant.
; CHECK-LABEL: define i32 @volatile_load
; CHECK: for.body:
; CHECK: %2 = load i32, i32*
; CHECK: %3 = load volatile i32, i32*
; CHECK: for.cond.for.end_crit_edge:
define i32 @volatile_load(i32 %n) {
entry:
%cmp6 = icmp sgt i32 %n, 0
br i1 %cmp6, label %for.body.lr.ph, label %for.end
for.body.lr.ph:
%0 = load i32*, i32** @a2, align 8, !tbaa !1
%1 = load i32*, i32** @a, align 8, !tbaa !1
br label %for.body
for.body:
%indvars.iv = phi i64 [ 0, %for.body.lr.ph ], [ %indvars.iv.next, %for.body ]
%s.09 = phi i32 [ 0, %for.body.lr.ph ], [ %add, %for.body ]
%p.08 = phi i32* [ %0, %for.body.lr.ph ], [ %incdec.ptr, %for.body ]
%2 = load i32, i32* %p.08, align 4, !tbaa !5
%arrayidx = getelementptr inbounds i32, i32* %1, i64 %indvars.iv
store i32 %2, i32* %arrayidx, align 4, !tbaa !5
%3 = load volatile i32, i32* %p.08, align 4, !tbaa !5
%add = add nsw i32 %3, %s.09
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%incdec.ptr = getelementptr inbounds i32, i32* %p.08, i64 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp ne i32 %lftr.wideiv, %n
br i1 %exitcond, label %for.body, label %for.cond.for.end_crit_edge
for.cond.for.end_crit_edge:
%add.lcssa = phi i32 [ %add, %for.body ]
br label %for.end
for.end:
%s.0.lcssa = phi i32 [ %add.lcssa, %for.cond.for.end_crit_edge ], [ 0, %entry ]
ret i32 %s.0.lcssa
}
; %1 is partially redundant if %0 can be widened to a 64-bit load.
; But we should not widen %0 to 64-bit load.
; CHECK-LABEL: define i32 @overaligned_load
; CHECK: if.then:
; CHECK-NOT: %0 = load i64
; CHECK-NOT: [[LSHR:%[0-9]+]] = lshr i64 %0, 32, !dbg [[LSHR_LOC:![0-9]+]]
; CHECK-NOT: trunc i64 [[LSHR]] to i32
; CHECK: if.end:
; CHECK: %1 = load i32, i32*
; CHECK-NOT: [[LSHR_LOC]] = !DILocation(line: 101, column: 1, scope: !{{.*}})
define i32 @overaligned_load(i32 %a, i32* nocapture %b) !dbg !13 {
entry:
%cmp = icmp sgt i32 %a, 0, !dbg !14
br i1 %cmp, label %if.then, label %if.else, !dbg !14
if.then:
%0 = load i32, i32* getelementptr inbounds (%struct.S1, %struct.S1* @s1, i64 0, i32 0), align 8, !tbaa !5, !dbg !15
br label %if.end, !dbg !15
if.else:
%arrayidx = getelementptr inbounds i32, i32* %b, i64 2, !dbg !16
store i32 10, i32* %arrayidx, align 4, !tbaa !5, !dbg !16
br label %if.end, !dbg !16
if.end:
%i.0 = phi i32 [ %0, %if.then ], [ 0, %if.else ]
%p.0 = phi i32* [ getelementptr inbounds (%struct.S1, %struct.S1* @s1, i64 0, i32 0), %if.then ], [ %b, %if.else ]
%add.ptr = getelementptr inbounds i32, i32* %p.0, i64 1, !dbg !17
%1 = load i32, i32* %add.ptr, align 4, !tbaa !5, !dbg !17
%add1 = add nsw i32 %1, %i.0, !dbg !17
ret i32 %add1, !dbg !17
}
!1 = !{!2, !2, i64 0}
!2 = !{!"any pointer", !3, i64 0}
!3 = !{!"omnipotent char", !4, i64 0}
!4 = !{!"Simple C/C++ TBAA"}
!5 = !{!6, !6, i64 0}
!6 = !{!"int", !3, i64 0}
!llvm.module.flags = !{!7, !8, !9}
!llvm.dbg.cu = !{!18}
!7 = !{i32 2, !"Dwarf Version", i32 4}
!8 = !{i32 2, !"Debug Info Version", i32 3}
!9 = !{i32 1, !"PIC Level", i32 2}
!10 = !{}
!11 = !DISubroutineType(types: !10)
!12 = !DIFile(filename: "test.cpp", directory: "/tmp")
!13 = distinct !DISubprogram(name: "test", scope: !12, file: !12, line: 99, type: !11, isLocal: false, isDefinition: true, scopeLine: 100, flags: DIFlagPrototyped, isOptimized: false, unit: !18, retainedNodes: !10)
!14 = !DILocation(line: 100, column: 1, scope: !13)
!15 = !DILocation(line: 101, column: 1, scope: !13)
!16 = !DILocation(line: 102, column: 1, scope: !13)
!17 = !DILocation(line: 103, column: 1, scope: !13)
!18 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang",
file: !12,
isOptimized: true, flags: "-O2",
splitDebugFilename: "abc.debug", emissionKind: 2)
|