diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
--- a/llvm/include/llvm/IR/DebugInfoMetadata.h
+++ b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -1818,6 +1818,7 @@
   DISubprogram *getDeclaration() const {
     return cast_or_null<DISubprogram>(getRawDeclaration());
   }
+  void replaceDeclaration(DISubprogram *Decl) { replaceOperandWith(6, Decl); }
   DINodeArray getRetainedNodes() const {
     return cast_or_null<MDTuple>(getRawRetainedNodes());
   }
diff --git a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
--- a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
@@ -937,9 +937,22 @@
     // abstract specification, since the DWARF backend expects the
     // abstract specification to contain the linkage name and asserts
     // that they are identical.
-    if (!SP->getDeclaration() && SP->getUnit() &&
-        SP->getUnit()->getSourceLanguage() == dwarf::DW_LANG_Swift)
+    if (SP->getUnit() &&
+        SP->getUnit()->getSourceLanguage() == dwarf::DW_LANG_Swift) {
       SP->replaceLinkageName(MDString::get(Context, NewF->getName()));
+      if (auto *Decl = SP->getDeclaration()) {
+        auto *NewDecl = DISubprogram::get(
+            Decl->getContext(), Decl->getScope(), Decl->getName(),
+            NewF->getName(), Decl->getFile(), Decl->getLine(), Decl->getType(),
+            Decl->getScopeLine(), Decl->getContainingType(),
+            Decl->getVirtualIndex(), Decl->getThisAdjustment(),
+            Decl->getFlags(), Decl->getSPFlags(), Decl->getUnit(),
+            Decl->getTemplateParams(), nullptr, Decl->getRetainedNodes(),
+            Decl->getThrownTypes(), Decl->getAnnotations(),
+            Decl->getTargetFuncName());
+        SP->replaceDeclaration(NewDecl);
+      }
+    }
   }
 
   NewF->setLinkage(savedLinkage);
diff --git a/llvm/test/Transforms/Coroutines/coro-async-declaration.ll b/llvm/test/Transforms/Coroutines/coro-async-declaration.ll
--- a/llvm/test/Transforms/Coroutines/coro-async-declaration.ll
+++ b/llvm/test/Transforms/Coroutines/coro-async-declaration.ll
@@ -305,9 +305,11 @@
 !43 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "$s4main5entryOXMtD", file: !44, size: 8, flags: DIFlagArtificial, runtimeLang: DW_LANG_Swift, identifier: "$s4main5entryOXMtD")
 !44 = !DIFile(filename: "<compiler-generated>", directory: "")
 ; CHECK-DAG: ![[DECL:[0-9]+]] = !DISubprogram({{.*}}, linkageName: "$s4main5entryOAAyyYaFZ"
+; CHECK-DAG: ![[DECL_Q0:[0-9]+]] = !DISubprogram({{.*}}, linkageName: "$s4main5entryOAAyyYaFZTQ0_"
+; CHECK-DAG: ![[DECL_Y1:[0-9]+]] = !DISubprogram({{.*}}, linkageName: "$s4main5entryOAAyyYaFZTY1_"
 ; CHECK-DAG: distinct !DISubprogram({{.*}}, linkageName: "$s4main5entryOAAyyYaFZ"{{.*}}, declaration: ![[DECL]]
-; CHECK-DAG: distinct !DISubprogram({{.*}}, linkageName: "$s4main5entryOAAyyYaFZ"{{.*}}, declaration: ![[DECL]]
-; CHECK-DAG: distinct !DISubprogram({{.*}}, linkageName: "$s4main5entryOAAyyYaFZ"{{.*}}, declaration: ![[DECL]]
+; CHECK-DAG: distinct !DISubprogram({{.*}}, linkageName: "$s4main5entryOAAyyYaFZTQ0_"{{.*}}, declaration: ![[DECL_Q0]]
+; CHECK-DAG: distinct !DISubprogram({{.*}}, linkageName: "$s4main5entryOAAyyYaFZTY1_"{{.*}}, declaration: ![[DECL_Y1]]
 !45 = !DISubprogram(name: "main", linkageName: "$s4main5entryOAAyyYaFZ", scope: !39, file: !1, line: 2, type: !40, scopeLine: 2, spFlags: 0)
 !46 = !{!47, !49}
 !47 = !DILocalVariable(name: "self", arg: 1, scope: !38, file: !1, line: 2, type: !48, flags: DIFlagArtificial)