1; RUN: opt -mem2reg %s -S -o - | FileCheck %s
2
3;; Check that mem2reg removes dbg.value(%local, DIExpression(DW_OP_deref...))
4;; that instcombine LowerDbgDeclare inserted before the call to 'esc' when
5;; promoting the alloca %local after 'esc' has been inlined. Without this we
6;; provide no location for 'local', even though it is provably constant
7;; throughout after inlining.
8;;
9;; $ clang reduce.c -O2 -g -emit-llvm -S -o tmp.ll -Xclang -disable-llvm-passes
10;; $ opt tmp.ll -o - -instcombine -inline -S
11;; $ cat reduce.c
12;; __attribute__((__always_inline__))
13;; static void esc(unsigned char **c) {
14;;   *c += 4;
15;; }
16;; void fun() {
17;;   unsigned char *local = 0;
18;;   esc(&local);
19;; }
20
21; CHECK: define dso_local void @fun()
22; CHECK-NEXT: entry:
23; CHECK-NEXT: call void @llvm.dbg.value(metadata i8* null, metadata ![[LOCAL:[0-9]+]], metadata !DIExpression())
24; CHECK-NOT: call void @llvm.dbg.value({{.*}}, metadata ![[LOCAL]]
25; CHECK: ![[LOCAL]] = !DILocalVariable(name: "local",
26
27define dso_local void @fun() !dbg !7 {
28entry:
29  %local = alloca i8*, align 8
30  %0 = bitcast i8** %local to i8*, !dbg !14
31  call void @llvm.lifetime.start.p0i8(i64 8, i8* nonnull %0) #3, !dbg !14
32  call void @llvm.dbg.value(metadata i8* null, metadata !11, metadata !DIExpression()), !dbg !15
33  store i8* null, i8** %local, align 8, !dbg !16
34  call void @llvm.dbg.value(metadata i8** %local, metadata !11, metadata !DIExpression(DW_OP_deref)), !dbg !15
35  call void @llvm.dbg.value(metadata i8** %local, metadata !21, metadata !DIExpression()), !dbg !27
36  call void @llvm.dbg.value(metadata i8** %local, metadata !21, metadata !DIExpression()), !dbg !27
37  %1 = load i8*, i8** %local, align 8, !dbg !29
38  %add.ptr.i = getelementptr inbounds i8, i8* %1, i64 4, !dbg !29
39  store i8* %add.ptr.i, i8** %local, align 8, !dbg !29
40  %2 = bitcast i8** %local to i8*, !dbg !30
41  call void @llvm.lifetime.end.p0i8(i64 8, i8* nonnull %2) #3, !dbg !30
42  ret void, !dbg !30
43}
44
45declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture)
46declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture)
47declare void @llvm.dbg.value(metadata, metadata, metadata)
48
49!llvm.dbg.cu = !{!0}
50!llvm.module.flags = !{!3, !4, !5}
51!llvm.ident = !{!6}
52
53!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 12.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
54!1 = !DIFile(filename: "reduce.c", directory: "/")
55!2 = !{}
56!3 = !{i32 7, !"Dwarf Version", i32 4}
57!4 = !{i32 2, !"Debug Info Version", i32 3}
58!5 = !{i32 1, !"wchar_size", i32 4}
59!6 = !{!"clang version 12.0.0"}
60!7 = distinct !DISubprogram(name: "fun", scope: !1, file: !1, line: 5, type: !8, scopeLine: 5, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !10)
61!8 = !DISubroutineType(types: !9)
62!9 = !{null}
63!10 = !{!11}
64!11 = !DILocalVariable(name: "local", scope: !7, file: !1, line: 6, type: !12)
65!12 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !13, size: 64)
66!13 = !DIBasicType(name: "unsigned char", size: 8, encoding: DW_ATE_unsigned_char)
67!14 = !DILocation(line: 6, column: 3, scope: !7)
68!15 = !DILocation(line: 0, scope: !7)
69!16 = !DILocation(line: 6, column: 18, scope: !7)
70!21 = !DILocalVariable(name: "c", arg: 1, scope: !22, file: !1, line: 2, type: !25)
71!22 = distinct !DISubprogram(name: "esc", scope: !1, file: !1, line: 2, type: !23, scopeLine: 2, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !26)
72!23 = !DISubroutineType(types: !24)
73!24 = !{null, !25}
74!25 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !12, size: 64)
75!26 = !{!21}
76!27 = !DILocation(line: 0, scope: !22, inlinedAt: !28)
77!28 = distinct !DILocation(line: 7, column: 3, scope: !7)
78!29 = !DILocation(line: 3, column: 6, scope: !22, inlinedAt: !28)
79!30 = !DILocation(line: 8, column: 1, scope: !7)
80