Index: include/llvm/IR/Constant.h
===================================================================
--- include/llvm/IR/Constant.h
+++ include/llvm/IR/Constant.h
@@ -148,7 +148,7 @@
   /// them. This method is useful for clients that want to check to see if a
   /// global is unused, but don't want to deal with potentially dead constants
   /// hanging off of the globals.
-  void removeDeadConstantUsers() const;
+  void removeDeadConstantUsers(bool SkipMetadataUses = true) const;
 
   Constant *stripPointerCasts() {
     return cast<Constant>(Value::stripPointerCasts());
Index: lib/IR/Constants.cpp
===================================================================
--- lib/IR/Constants.cpp
+++ lib/IR/Constants.cpp
@@ -466,16 +466,19 @@
 /// removeDeadUsersOfConstant - If the specified constantexpr is dead, remove
 /// it.  This involves recursively eliminating any dead users of the
 /// constantexpr.
-static bool removeDeadUsersOfConstant(const Constant *C) {
+static bool removeDeadUsersOfConstant(const Constant *C, bool SkipMetadataUses) {
   if (isa<GlobalValue>(C)) return false; // Cannot remove this
 
   while (!C->use_empty()) {
     const Constant *User = dyn_cast<Constant>(C->user_back());
     if (!User) return false; // Non-constant usage;
-    if (!removeDeadUsersOfConstant(User))
+    if (!removeDeadUsersOfConstant(User, SkipMetadataUses))
       return false; // Constant wasn't dead
   }
 
+  if (!SkipMetadataUses && C->isUsedByMetadata())
+    return false;
+
   const_cast<Constant*>(C)->destroyConstant();
   return true;
 }
@@ -485,7 +488,7 @@
 /// off of this constant, remove them.  This method is useful for clients
 /// that want to check to see if a global is unused, but don't want to deal
 /// with potentially dead constants hanging off of the globals.
-void Constant::removeDeadConstantUsers() const {
+void Constant::removeDeadConstantUsers(bool SkipMetadataUses) const {
   Value::const_user_iterator I = user_begin(), E = user_end();
   Value::const_user_iterator LastNonDeadUser = E;
   while (I != E) {
@@ -496,7 +499,7 @@
       continue;
     }
 
-    if (!removeDeadUsersOfConstant(User)) {
+    if (!removeDeadUsersOfConstant(User, SkipMetadataUses)) {
       // If the constant wasn't dead, remember that this was the last live use
       // and move on to the next constant.
       LastNonDeadUser = I;
Index: lib/Transforms/IPO/GlobalOpt.cpp
===================================================================
--- lib/Transforms/IPO/GlobalOpt.cpp
+++ lib/Transforms/IPO/GlobalOpt.cpp
@@ -1683,8 +1683,19 @@
   return true;
 }
 
+/// Return true if GV is only used by constants which are only used by metadata.
+static bool onlyUsedByMetadata(GlobalValue &GV) {
+  for (auto *U : GV.users())
+    if (auto *C = dyn_cast<Constant>(U)) {
+      if (!(C->use_empty() && C->isUsedByMetadata()))
+        return false;
+    } else
+      return false;
+  return true;
+}
+
 bool GlobalOpt::deleteIfDead(GlobalValue &GV) {
-  GV.removeDeadConstantUsers();
+  GV.removeDeadConstantUsers(/* skip metadata uses */false);
 
   if (!GV.isDiscardableIfUnused())
     return false;
@@ -1697,7 +1708,7 @@
   if (auto *F = dyn_cast<Function>(&GV))
     Dead = F->isDefTriviallyDead();
   else
-    Dead = GV.use_empty();
+    Dead = GV.use_empty() || onlyUsedByMetadata(GV);
   if (!Dead)
     return false;
 
Index: test/Transforms/GlobalOpt/debug-info-global-vars.ll
===================================================================
--- /dev/null
+++ test/Transforms/GlobalOpt/debug-info-global-vars.ll
@@ -0,0 +1,34 @@
+; RUN: opt %s -globalopt -S -o - | FileCheck %s
+; Built and reduced from 'const char version[] = "test";' with -fsanitize=address.
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx"
+
+; CHECK: @version = constant
+@version = constant { [5 x i8], [59 x i8] } { [5 x i8] c"test\00", [59 x i8] zeroinitializer }, align 32
+@unused = internal global { [5 x i8], [59 x i8] } { [5 x i8] c"test\00", [59 x i8] zeroinitializer }, align 32
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!10, !11, !12}
+!llvm.ident = !{!13}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: 1, enums: !2, globals: !3)
+!1 = !DIFile(filename: "version.c", directory: "/Volumes/Data/radar/24899262")
+!2 = !{}
+!3 = !{!4, !14}
+; Check that we don't drop the debug info for this global variable.
+; CHECK: !DIGlobalVariable(name: "version", {{.*}}, variable: [5 x i8]*
+!4 = !DIGlobalVariable(name: "version", scope: !0, file: !1, line: 2, type: !5, isLocal: false, isDefinition: true, variable: [5 x i8]* getelementptr inbounds ({ [5 x i8], [59 x i8] }, { [5 x i8], [59 x i8] }* @version, i32 0, i32 0))
+!5 = !DICompositeType(tag: DW_TAG_array_type, baseType: !6, size: 40, align: 8, elements: !8)
+!6 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !7)
+!7 = !DIBasicType(name: "char", size: 8, align: 8, encoding: DW_ATE_signed_char)
+!8 = !{!9}
+!9 = !DISubrange(count: 5)
+!10 = !{i32 2, !"Dwarf Version", i32 2}
+!11 = !{i32 2, !"Debug Info Version", i32 3}
+!12 = !{i32 1, !"PIC Level", i32 2}
+!13 = !{!"clang version 3.9.0 "}
+; Check that we do drop the debug info for this global variable.
+; CHECK: !DIGlobalVariable(name: "unused",
+; CHECK-NOT: variable: [5 x i8]*
+!14 = !DIGlobalVariable(name: "unused", scope: !0, file: !1, line: 2, type: !5, isLocal: false, isDefinition: true, variable: [5 x i8]* getelementptr inbounds ({ [5 x i8], [59 x i8] }, { [5 x i8], [59 x i8] }* @unused, i32 0, i32 0))