diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 3ac4899f544..d58e47eaf03 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -762,8 +762,13 @@ void DwarfDebug::beginModule() {
     for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
       SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
     DIArray EnumTypes = CUNode.getEnumTypes();
-    for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i)
-      CU.getOrCreateTypeDIE(EnumTypes.getElement(i));
+    for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
+      DIType Ty(EnumTypes.getElement(i));
+      // The enum types array by design contains pointers to
+      // MDNodes rather than DIRefs. Unique them here.
+      DIType UniqueTy(resolve(Ty.getRef()));
+      CU.getOrCreateTypeDIE(UniqueTy);
+    }
     DIArray RetainedTypes = CUNode.getRetainedTypes();
     for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
       DIType Ty(RetainedTypes.getElement(i));
diff --git a/test/DebugInfo/enum-types.ll b/test/DebugInfo/enum-types.ll
new file mode 100644
index 00000000000..bcdba37f197
--- /dev/null
+++ b/test/DebugInfo/enum-types.ll
@@ -0,0 +1,78 @@
+; REQUIRES: object-emission
+;
+; RUN: %llc_dwarf -filetype=obj -O0 < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
+
+; Make sure we can handle enums with the same identifier but in enum types of
+; different compile units.
+; rdar://17628609
+
+; CHECK: DW_TAG_compile_unit
+; CHECK: 0x[[ENUM:.*]]: DW_TAG_enumeration_type
+; CHECK-NEXT:   DW_AT_name {{.*}} "EA"
+; CHECK: DW_TAG_subprogram
+; CHECK: DW_AT_MIPS_linkage_name {{.*}} "_Z4topA2EA"
+; CHECK: DW_TAG_formal_parameter
+; CHECK: DW_AT_type [DW_FORM_ref4] (cu + 0x{{.*}} => {0x[[ENUM]]})
+
+; CHECK: DW_TAG_compile_unit
+; CHECK: DW_TAG_subprogram
+; CHECK:   DW_AT_MIPS_linkage_name {{.*}} "_Z4topB2EA"
+; CHECK: DW_TAG_formal_parameter
+; CHECK: DW_AT_type [DW_FORM_ref_addr] {{.*}}[[ENUM]]
+
+; Function Attrs: nounwind ssp uwtable
+define void @_Z4topA2EA(i32 %sa) #0 {
+entry:
+  %sa.addr = alloca i32, align 4
+  store i32 %sa, i32* %sa.addr, align 4
+  call void @llvm.dbg.declare(metadata !{i32* %sa.addr}, metadata !22), !dbg !23
+  ret void, !dbg !24
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata) #1
+
+; Function Attrs: nounwind ssp uwtable
+define void @_Z4topB2EA(i32 %sa) #0 {
+entry:
+  %sa.addr = alloca i32, align 4
+  store i32 %sa, i32* %sa.addr, align 4
+  call void @llvm.dbg.declare(metadata !{i32* %sa.addr}, metadata !25), !dbg !26
+  ret void, !dbg !27
+}
+
+attributes #0 = { nounwind ssp uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!0, !12}
+!llvm.module.flags = !{!19, !20}
+!llvm.ident = !{!21, !21}
+
+!0 = metadata !{i32 786449, metadata !1, i32 4, metadata !"clang version 3.5.0 (trunk 214102:214133) (llvm/trunk 214102:214132)", i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !6, metadata !11, metadata !11, metadata !"", i32 1} ; [ DW_TAG_compile_unit ] [<unknown>] [DW_LANG_C_plus_plus]
+!1 = metadata !{metadata !"a.cpp", metadata !""}
+!2 = metadata !{metadata !3}
+!3 = metadata !{i32 786436, metadata !1, null, metadata !"EA", i32 1, i64 32, i64 32, i32 0, i32 0, null, metadata !4, i32 0, null, null, metadata !"_ZTS2EA"} ; [ DW_TAG_enumeration_type ] [EA] [line 1, size 32, align 32, offset 0] [def] [from ]
+!4 = metadata !{metadata !5}
+!5 = metadata !{i32 786472, metadata !"EA_0", i64 0} ; [ DW_TAG_enumerator ] [EA_0 :: 0]
+!6 = metadata !{metadata !7}
+!7 = metadata !{i32 786478, metadata !1, metadata !8, metadata !"topA", metadata !"topA", metadata !"_Z4topA2EA", i32 5, metadata !9, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, void (i32)* @_Z4topA2EA, null, null, metadata !11, i32 5} ; [ DW_TAG_subprogram ] [line 5] [def] [topA]
+!8 = metadata !{i32 786473, metadata !1}          ; [ DW_TAG_file_type ] [a.cpp]
+!9 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !10, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!10 = metadata !{null, metadata !"_ZTS2EA"}
+!11 = metadata !{}
+!12 = metadata !{i32 786449, metadata !13, i32 4, metadata !"clang version 3.5.0 (trunk 214102:214133) (llvm/trunk 214102:214132)", i1 false, metadata !"", i32 0, metadata !14, metadata !14, metadata !16, metadata !11, metadata !11, metadata !"", i32 1} ; [ DW_TAG_compile_unit ] [b.cpp] [DW_LANG_C_plus_plus]
+!13 = metadata !{metadata !"b.cpp", metadata !""}
+!14 = metadata !{metadata !15}
+!15 = metadata !{i32 786436, metadata !13, null, metadata !"EA", i32 1, i64 32, i64 32, i32 0, i32 0, null, metadata !4, i32 0, null, null, metadata !"_ZTS2EA"} ; [ DW_TAG_enumeration_type ] [EA] [line 1, size 32, align 32, offset 0] [def] [from ]
+!16 = metadata !{metadata !17}
+!17 = metadata !{i32 786478, metadata !13, metadata !18, metadata !"topB", metadata !"topB", metadata !"_Z4topB2EA", i32 5, metadata !9, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, void (i32)* @_Z4topB2EA, null, null, metadata !11, i32 5} ; [ DW_TAG_subprogram ] [line 5] [def] [topB]
+!18 = metadata !{i32 786473, metadata !13}        ; [ DW_TAG_file_type ] [b.cpp]
+!19 = metadata !{i32 2, metadata !"Dwarf Version", i32 2}
+!20 = metadata !{i32 2, metadata !"Debug Info Version", i32 1}
+!21 = metadata !{metadata !"clang version 3.5.0 (trunk 214102:214133) (llvm/trunk 214102:214132)"}
+!22 = metadata !{i32 786689, metadata !7, metadata !"sa", metadata !8, i32 16777221, metadata !"_ZTS2EA", i32 0, i32 0} ; [ DW_TAG_arg_variable ] [sa] [line 5]
+!23 = metadata !{i32 5, i32 14, metadata !7, null}
+!24 = metadata !{i32 6, i32 1, metadata !7, null}
+!25 = metadata !{i32 786689, metadata !17, metadata !"sa", metadata !18, i32 16777221, metadata !"_ZTS2EA", i32 0, i32 0} ; [ DW_TAG_arg_variable ] [sa] [line 5]
+!26 = metadata !{i32 5, i32 14, metadata !17, null}
+!27 = metadata !{i32 6, i32 1, metadata !17, null}