Index: tools/llvm-project/llvm/lib/Transforms/IPO/GlobalOpt.cpp
===================================================================
--- tools/llvm-project/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ tools/llvm-project/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -28,6 +28,7 @@
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/DIBuilder.h"
 #include "llvm/IR/GetElementPtrTypeIterator.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
@@ -86,6 +87,7 @@
                                const GlobalStatus &GS);
     bool OptimizeEmptyGlobalCXXDtors(Function *CXAAtExitFn);
 
+    std::unique_ptr<DIBuilder> DIB;
     TargetLibraryInfo *TLI;
     SmallSet<const Comdat *, 8> NotDiscardableComdats;
   };
@@ -1749,6 +1751,16 @@
   }
 }
 
+static DIGlobalVariable *FindDebugInfo(GlobalVariable *GV) {
+  DebugInfoFinder F;
+  F.processModule(*GV->getParent());
+  for (DICompileUnit *DIC : F.compile_units())
+    for (DIGlobalVariable *DIG : DIC->getGlobalVariables())
+      if (DIG->getVariable() == GV)
+          return DIG;
+  return nullptr;
+}
+
 /// Analyze the specified global variable and optimize
 /// it if possible.  If we make a change, return true.
 bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV,
@@ -1776,11 +1788,26 @@
     // FIXME: Pass Global's alignment when globals have alignment
     AllocaInst *Alloca = new AllocaInst(ElemTy, nullptr,
                                         GV->getName(), &FirstI);
+    StoreInst *Store = nullptr;
     if (!isa<UndefValue>(GV->getInitializer()))
-      new StoreInst(GV->getInitializer(), Alloca, &FirstI);
+      Store = new StoreInst(GV->getInitializer(), Alloca, &FirstI);
+
+    if (DIGlobalVariable *D = FindDebugInfo(GV)) {
+      if (DIType *T = dyn_cast<DIType>(D->getRawType())) {
+        DEBUG(dbgs() << "                   ... and transferring its DebugInfo\n");
+        auto *Scope = D->getScope();
+        auto *Variable = DIB->createAutoVariable(Scope,
+                                                 D->getLinkageName(),
+                                                 D->getFile(), D->getLine(),
+                                                 T);
+        auto *E = DIB->createExpression();
+        auto *DL = DILocation::get(GV->getContext(), D->getLine(), 0,
+                                   Scope);
+        DIB->insertDeclare(Alloca, Variable, E, DL, Store);
+      }
 
     makeAllConstantUsesInstructions(GV);
-    
+
     GV->replaceAllUsesWith(Alloca);
     GV->eraseFromParent();
     ++NumLocalized;
@@ -3062,6 +3089,7 @@
 }
 
 bool GlobalOpt::runOnModule(Module &M) {
+  DIB = llvm::make_unique<DIBuilder>(M, /*AllowUnresolved=*/ false);
   bool Changed = false;
 
   auto &DL = M.getDataLayout();