diff --git a/llvm/test/DebugInfo/Generic/double-declare.ll b/llvm/test/DebugInfo/Generic/double-declare.ll
new file mode 100644
index 0000000..6111d0b
--- /dev/null
+++ b/llvm/test/DebugInfo/Generic/double-declare.ll
@@ -0,0 +1,44 @@
+; RUN: %llc_dwarf -O0 -filetype=obj -o - < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
+; PR33157. Don't crash on duplicate dbg.declare.
+; CHECK: DW_TAG_formal_parameter
+; CHECK: DW_AT_location [DW_FORM_exprloc]
+; CHECK-NOT: DW_AT_location
+@g = external global i32
+@h = external global i32
+
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+
+define void @f(i32* byval %p, i1 %c) !dbg !5 {
+  br i1 %c, label %x, label %y
+
+x:
+  call void @llvm.dbg.declare(metadata i32* %p, metadata !10, metadata !DIExpression()), !dbg !12
+  store i32 42, i32* @g, !dbg !12
+  br label %done
+
+y:
+  call void @llvm.dbg.declare(metadata i32* %p, metadata !10, metadata !DIExpression()), !dbg !12
+  store i32 42, i32* @h, !dbg !12
+  br label %done
+
+done:
+  ret void
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!22, !23}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_ObjC, file: !1, producer: "clang version 5.0.0 ", isOptimized: true, runtimeVersion: 2, emissionKind: FullDebug)
+!1 = !DIFile(filename: "<stdin>", directory: "C:\5Csrc\5Cllvm-project\5Cbuild")
+!5 = distinct !DISubprogram(name: "f", isLocal: true, isDefinition: true, scopeLine: 37, flags: DIFlagPrototyped, isOptimized: true, unit: !0, type: !99, scope: !1)
+!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!10 = !DILocalVariable(name: "aRect", arg: 1, scope: !11, file: !1, line: 38, type: !6)
+!11 = distinct !DILexicalBlock(scope: !98, file: !1, line: 38)
+!12 = !DILocation(line: 43, scope: !11, inlinedAt: !13)
+!13 = distinct !DILocation(line: 43, scope: !5)
+!22 = !{i32 2, !"Dwarf Version", i32 4}
+!23 = !{i32 2, !"Debug Info Version", i32 3}
+!62 = !{!10}
+!98 = distinct !DISubprogram(name: "NSMaxX", scope: !1, file: !1, line: 27, isLocal: true, isDefinition: true, scopeLine: 27, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !62, type: !99)
+!99 = !DISubroutineType(types: !100)
+!100 = !{null}