Index: lib/CodeGen/CGExpr.cpp
===================================================================
--- lib/CodeGen/CGExpr.cpp
+++ lib/CodeGen/CGExpr.cpp
@@ -2975,6 +2975,7 @@
   bool WithDiag = !CGM.getCodeGenOpts().SanitizeTrap.has(Kind);
 
   llvm::CallInst *CheckCall;
+  llvm::Constant *SlowPathFn;
   if (WithDiag) {
     llvm::Constant *Info = llvm::ConstantStruct::getAnon(StaticArgs);
     auto *InfoPtr =
@@ -2983,20 +2984,20 @@
     InfoPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
     CGM.getSanitizerMetadata()->disableSanitizerForGlobal(InfoPtr);
 
-    llvm::Constant *SlowPathDiagFn = CGM.getModule().getOrInsertFunction(
+    SlowPathFn = CGM.getModule().getOrInsertFunction(
         "__cfi_slowpath_diag",
         llvm::FunctionType::get(VoidTy, {Int64Ty, Int8PtrTy, Int8PtrTy},
                                 false));
     CheckCall = Builder.CreateCall(
-        SlowPathDiagFn,
-        {TypeId, Ptr, Builder.CreateBitCast(InfoPtr, Int8PtrTy)});
+        SlowPathFn, {TypeId, Ptr, Builder.CreateBitCast(InfoPtr, Int8PtrTy)});
   } else {
-    llvm::Constant *SlowPathFn = CGM.getModule().getOrInsertFunction(
+    SlowPathFn = CGM.getModule().getOrInsertFunction(
         "__cfi_slowpath",
         llvm::FunctionType::get(VoidTy, {Int64Ty, Int8PtrTy}, false));
     CheckCall = Builder.CreateCall(SlowPathFn, {TypeId, Ptr});
   }
 
+  CGM.setDSOLocal(cast<llvm::GlobalValue>(SlowPathFn->stripPointerCasts()));
   CheckCall->setDoesNotThrow();
 
   EmitBlock(Cont);
Index: test/CodeGen/cfi-icall-cross-dso.c
===================================================================
--- test/CodeGen/cfi-icall-cross-dso.c
+++ test/CodeGen/cfi-icall-cross-dso.c
@@ -39,6 +39,11 @@
 // MS-DIAG: call void @__cfi_slowpath_diag(i64 4195979634929632483, i8* %{{.*}}, {{.*}}@[[DATA]]{{.*}}) {{.*}}, !nosanitize
 // MS-TRAP: call void @__cfi_slowpath(i64 4195979634929632483, i8* %{{.*}}) {{.*}}, !nosanitize
 
+// ITANIUM-DIAG: declare void @__cfi_slowpath_diag(
+// ITANIUM-TRAP: declare void @__cfi_slowpath(
+// MS-DIAG: declare dso_local void @__cfi_slowpath_diag(
+// MS-TRAP: declare dso_local void @__cfi_slowpath(
+
 void caller(void (*f)()) {
   f();
 }