diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -567,6 +567,11 @@
 
   auto *SP = cast<DISubprogram>(Scope->getScopeNode());
 
+  // Handling a case with LTO where function is inlined from CU which doesn't
+  // have SplitDebugInlining enabled into one that does.
+  if (SrcCU.getCUNode()->getSplitDebugInlining())
+    SP->getUnit()->setSplitDebugInlining(true);
+
   // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
   // was inlined from another compile unit.
   if (useSplitDwarf() && !shareAcrossDWOCUs() && !SP->getUnit()->getSplitDebugInlining())
diff --git a/llvm/test/DebugInfo/X86/mixDebugInliing.test b/llvm/test/DebugInfo/X86/mixDebugInliing.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/DebugInfo/X86/mixDebugInliing.test
@@ -0,0 +1,107 @@
+; RUN: llc -mtriple=x86_64-linux -split-dwarf-file=foo.dwo -filetype=obj -o %t < %s
+; RUN: llvm-dwarfdump --debug-info --show-form --verbose %t | FileCheck -check-prefix=CHECK %s
+
+; CHECK:        DW_TAG_compile_unit
+; CHECK-NEXT:       DW_AT_stmt_list
+; CHECK-NEXT:       DW_AT_comp_dir
+; CHECK-NEXT:       DW_AT_GNU_pubnames
+; CHECK-NEXT:       DW_AT_GNU_dwo_name
+; CHECK-NEXT:       DW_AT_GNU_dwo_id
+; CHECK-NEXT:       DW_AT_low_pc
+; CHECK-NEXT:       DW_AT_high_pc
+; CHECK-NEXT:       DW_AT_GNU_addr_base
+; CHECK-EMPTY:
+; CHECK-NEXT:   DW_TAG_subprogram
+; CHECK-NEXT:       DW_AT_low_pc
+; CHECK-NEXT:       DW_AT_high_pc
+; CHECK-NEXT:       DW_AT_name
+; CHECK-EMPTY:
+; CHECK-NEXT:   DW_TAG_inlined_subroutine
+; CHECK-NEXT:       DW_AT_abstract_origin
+; CHECK-NEXT:       DW_AT_low_pc
+; CHECK-NEXT:       DW_AT_high_pc
+; CHECK-NEXT:       DW_AT_call_file
+; CHECK-NEXT:       DW_AT_call_line
+; CHECK-NEXT:       DW_AT_call_column
+
+; ModuleID = 'mainhelper.ll'
+source_filename = "llvm-link"
+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"
+
+; Function Attrs: noinline norecurse optnone uwtable mustprogress
+define dso_local i32 @main(i32 %argc, i8** %argv) #0 !dbg !9 {
+entry:
+  %x.addr.i = alloca i32, align 4
+  %retval = alloca i32, align 4
+  %argc.addr = alloca i32, align 4
+  %argv.addr = alloca i8**, align 8
+  store i32 0, i32* %retval, align 4
+  store i32 %argc, i32* %argc.addr, align 4
+  call void @llvm.dbg.declare(metadata i32* %argc.addr, metadata !16, metadata !DIExpression()), !dbg !17
+  store i8** %argv, i8*** %argv.addr, align 8
+  call void @llvm.dbg.declare(metadata i8*** %argv.addr, metadata !18, metadata !DIExpression()), !dbg !19
+  %0 = load i32, i32* %argc.addr, align 4, !dbg !20
+  store i32 %0, i32* %x.addr.i, align 4
+  call void @llvm.dbg.declare(metadata i32* %x.addr.i, metadata !21, metadata !DIExpression()), !dbg !25
+  %1 = load i32, i32* %x.addr.i, align 4, !dbg !27
+  %mul.i = mul nsw i32 %1, 2, !dbg !28
+  ret i32 %mul.i, !dbg !29
+}
+
+; Function Attrs: nofree nosync nounwind readnone speculatable willreturn
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+; Function Attrs: alwaysinline nounwind uwtable mustprogress
+define dso_local i32 @_Z4funci(i32 %x) #2 !dbg !22 {
+entry:
+  %x.addr = alloca i32, align 4
+  store i32 %x, i32* %x.addr, align 4
+  call void @llvm.dbg.declare(metadata i32* %x.addr, metadata !21, metadata !DIExpression()), !dbg !30
+  %0 = load i32, i32* %x.addr, align 4, !dbg !31
+  %mul = mul nsw i32 %0, 2, !dbg !32
+  ret i32 %mul, !dbg !33
+}
+
+attributes #0 = { noinline norecurse optnone uwtable mustprogress "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nofree nosync nounwind readnone speculatable willreturn }
+attributes #2 = { alwaysinline nounwind uwtable mustprogress "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0, !3}
+!llvm.ident = !{!5, !5}
+!llvm.module.flags = !{!6, !7, !8}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 12.0.1", isOptimized: false, runtimeVersion: 0, splitDebugFilename: "main.dwo", emissionKind: FullDebug, enums: !2, nameTableKind: GNU)
+!1 = !DIFile(filename: "main.cpp", directory: "bug2")
+!2 = !{}
+!3 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !4, producer: "clang version 12.0.1", isOptimized: false, runtimeVersion: 0, splitDebugFilename: "helper.dwo", emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: GNU)
+!4 = !DIFile(filename: "helper.cpp", directory: "bug2")
+!5 = !{!"clang version 12.0.1"}
+!6 = !{i32 7, !"Dwarf Version", i32 4}
+!7 = !{i32 2, !"Debug Info Version", i32 3}
+!8 = !{i32 1, !"wchar_size", i32 4}
+!9 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 2, type: !10, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!10 = !DISubroutineType(types: !11)
+!11 = !{!12, !12, !13}
+!12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!13 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !14, size: 64)
+!14 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !15, size: 64)
+!15 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
+!16 = !DILocalVariable(name: "argc", arg: 1, scope: !9, file: !1, line: 2, type: !12)
+!17 = !DILocation(line: 2, column: 14, scope: !9)
+!18 = !DILocalVariable(name: "argv", arg: 2, scope: !9, file: !1, line: 2, type: !13)
+!19 = !DILocation(line: 2, column: 26, scope: !9)
+!20 = !DILocation(line: 3, column: 15, scope: !9)
+!21 = !DILocalVariable(name: "x", arg: 1, scope: !22, file: !4, line: 1, type: !12)
+!22 = distinct !DISubprogram(name: "func", linkageName: "_Z4funci", scope: !4, file: !4, line: 1, type: !23, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !3, retainedNodes: !2)
+!23 = !DISubroutineType(types: !24)
+!24 = !{!12, !12}
+!25 = !DILocation(line: 1, column: 45, scope: !22, inlinedAt: !26)
+!26 = distinct !DILocation(line: 3, column: 10, scope: !9)
+!27 = !DILocation(line: 2, column: 11, scope: !22, inlinedAt: !26)
+!28 = !DILocation(line: 2, column: 13, scope: !22, inlinedAt: !26)
+!29 = !DILocation(line: 3, column: 3, scope: !9)
+!30 = !DILocation(line: 1, column: 45, scope: !22)
+!31 = !DILocation(line: 2, column: 11, scope: !22)
+!32 = !DILocation(line: 2, column: 13, scope: !22)
+!33 = !DILocation(line: 2, column: 4, scope: !22)