Index: lld/COFF/Driver.cpp
===================================================================
--- lld/COFF/Driver.cpp
+++ lld/COFF/Driver.cpp
@@ -843,6 +843,12 @@
     Config->Implib = Arg->getValue();
 
   // Handle /opt
+  // msvc linker uses /opt:noref by default in debug builds
+  if (Config->Debug) {
+    Config->DoGC = false;
+    Config->DoICF = false;
+  }
+
   for (auto *Arg : Args.filtered(OPT_opt)) {
     std::string Str = StringRef(Arg->getValue()).lower();
     SmallVector<StringRef, 1> Vec;