Index: llvm/trunk/lib/IR/Globals.cpp
===================================================================
--- llvm/trunk/lib/IR/Globals.cpp
+++ llvm/trunk/lib/IR/Globals.cpp
@@ -96,7 +96,6 @@
   if (const auto *GV = dyn_cast<GlobalObject>(Src)) {
     setAlignment(GV->getAlignment());
     setSection(GV->getSection());
-    setComdat(const_cast<GlobalObject *>(GV)->getComdat());
   }
 }
 
Index: llvm/trunk/lib/Linker/IRMover.cpp
===================================================================
--- llvm/trunk/lib/Linker/IRMover.cpp
+++ llvm/trunk/lib/Linker/IRMover.cpp
@@ -637,11 +637,6 @@
 
   NewGV->copyAttributesFrom(SGV);
 
-  // Don't copy the comdat, it's from the original module. We'll handle it
-  // later.
-  if (auto *NewGO = dyn_cast<GlobalObject>(NewGV))
-    NewGO->setComdat(nullptr);
-
   // Remove these copied constants in case this stays a declaration, since
   // they point to the source module. If the def is linked the values will
   // be mapped in during linkFunctionBody.
Index: llvm/trunk/lib/Transforms/IPO/DeadArgumentElimination.cpp
===================================================================
--- llvm/trunk/lib/Transforms/IPO/DeadArgumentElimination.cpp
+++ llvm/trunk/lib/Transforms/IPO/DeadArgumentElimination.cpp
@@ -147,6 +147,7 @@
   // Create the new function body and insert it into the module...
   Function *NF = Function::Create(NFTy, Fn.getLinkage());
   NF->copyAttributesFrom(&Fn);
+  NF->setComdat(Fn.getComdat());
   Fn.getParent()->getFunctionList().insert(Fn.getIterator(), NF);
   NF->takeName(&Fn);
 
@@ -813,6 +814,7 @@
   // Create the new function body and insert it into the module...
   Function *NF = Function::Create(NFTy, F->getLinkage());
   NF->copyAttributesFrom(F);
+  NF->setComdat(F->getComdat());
   NF->setAttributes(NewPAL);
   // Insert the new function before the old function, so we won't be processing
   // it again.