Index: llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -1439,15 +1439,14 @@
     }
   }
 
-  while (true) {
-    if (!T || T->isForwardDecl())
-      return false;
+  // Look through nested typedefs.
+  while (T->getTag() == dwarf::DW_TAG_typedef)
+    T = cast<DIDerivedType>(T)->getBaseType().resolve();
+
+  // Don't emit a UDT if we only have a forward declaration.
+  if (T && T->isForwardDecl())
+    return false;
 
-    const DIDerivedType *DT = dyn_cast<DIDerivedType>(T);
-    if (!DT)
-      return true;
-    T = DT->getBaseType().resolve();
-  }
   return true;
 }
 
Index: llvm/test/DebugInfo/COFF/udts-fwd.ll
===================================================================
--- /dev/null
+++ llvm/test/DebugInfo/COFF/udts-fwd.ll
@@ -0,0 +1,49 @@
+; RUN: llc -filetype=obj %s -o %t.obj
+; RUN: llvm-pdbutil dump -symbols %t.obj | FileCheck %s
+
+; Foo is forward declared here. Check that we emit the typedef for the pointer,
+; but not for the incomplete type. We adopted this behavior to make
+; /debug:fastlink more efficient, but it's not clear if it's still the right
+; behavior. This test just encodes it.
+
+; C++ source:
+; struct Foo;
+; typedef Foo TypedefFwd;
+; typedef TypedefFwd *TypedefFwdPtr;
+; TypedefFwdPtr global_ptr;
+
+; CHECK:                           Symbols
+; CHECK-NEXT: ============================================================
+; CHECK-NOT:   S_UDT {{.*}} `TypedefFwd`
+; CHECK:       S_UDT [size = {{.*}}] `TypedefFwdPtr`
+; CHECK-NOT:   S_UDT {{.*}} `TypedefFwd`
+
+
+; ModuleID = 't.cpp'
+source_filename = "t.cpp"
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc19.14.26433"
+
+%struct.Foo = type opaque
+
+@"?global_ptr@@3PEAUFoo@@EA" = dso_local global %struct.Foo* null, align 8, !dbg !0
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!10, !11, !12, !13}
+!llvm.ident = !{!14}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "global_ptr", linkageName: "?global_ptr@@3PEAUFoo@@EA", scope: !2, file: !3, line: 4, type: !6, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 8.0.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: None)
+!3 = !DIFile(filename: "t.cpp", directory: "C:\5Csrc\5Cllvm-project\5Cbuild", checksumkind: CSK_MD5, checksum: "eda0a32edcbd7e1d7b0220b9ef0192c7")
+!4 = !{}
+!5 = !{!0}
+!6 = !DIDerivedType(tag: DW_TAG_typedef, name: "TypedefFwdPtr", file: !3, line: 3, baseType: !7)
+!7 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !8, size: 64)
+!8 = !DIDerivedType(tag: DW_TAG_typedef, name: "TypedefFwd", file: !3, line: 2, baseType: !9)
+!9 = !DICompositeType(tag: DW_TAG_structure_type, name: "Foo", file: !3, line: 1, flags: DIFlagFwdDecl, identifier: ".?AUFoo@@")
+!10 = !{i32 2, !"CodeView", i32 1}
+!11 = !{i32 2, !"Debug Info Version", i32 3}
+!12 = !{i32 1, !"wchar_size", i32 2}
+!13 = !{i32 7, !"PIC Level", i32 2}
+!14 = !{!"clang version 8.0.0 "}