Index: lib/Driver/ToolChains/MinGW.cpp
===================================================================
--- lib/Driver/ToolChains/MinGW.cpp
+++ lib/Driver/ToolChains/MinGW.cpp
@@ -201,6 +201,14 @@
       CmdArgs.push_back("-Bdynamic");
   }
 
+  bool HasWindowsApp = false;
+  for (auto Lib : Args.getAllArgValues(options::OPT_l)) {
+    if (Lib == "windowsapp") {
+      HasWindowsApp = true;
+      break;
+    }
+  }
+
   if (!Args.hasArg(options::OPT_nostdlib)) {
     if (!Args.hasArg(options::OPT_nodefaultlibs)) {
       if (Args.hasArg(options::OPT_static))
@@ -223,15 +231,19 @@
       if (Args.hasArg(options::OPT_pthread))
         CmdArgs.push_back("-lpthread");
 
-      // add system libraries
-      if (Args.hasArg(options::OPT_mwindows)) {
-        CmdArgs.push_back("-lgdi32");
-        CmdArgs.push_back("-lcomdlg32");
+      if (!HasWindowsApp) {
+        // Add system libraries. If linking to libwindowsapp.a, that import
+        // library replaces all these and we shouldn't accidentally try to
+        // link to the normal desktop mode dlls.
+        if (Args.hasArg(options::OPT_mwindows)) {
+          CmdArgs.push_back("-lgdi32");
+          CmdArgs.push_back("-lcomdlg32");
+        }
+        CmdArgs.push_back("-ladvapi32");
+        CmdArgs.push_back("-lshell32");
+        CmdArgs.push_back("-luser32");
+        CmdArgs.push_back("-lkernel32");
       }
-      CmdArgs.push_back("-ladvapi32");
-      CmdArgs.push_back("-lshell32");
-      CmdArgs.push_back("-luser32");
-      CmdArgs.push_back("-lkernel32");
 
       if (Args.hasArg(options::OPT_static))
         CmdArgs.push_back("--end-group");
Index: test/Driver/mingw-windowsapp.c
===================================================================
--- test/Driver/mingw-windowsapp.c
+++ test/Driver/mingw-windowsapp.c
@@ -0,0 +1,6 @@
+// RUN: %clang -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_DEFAULT %s
+// RUN: %clang -v -target i686-pc-windows-gnu -### %s -lwindowsapp 2>&1 | FileCheck -check-prefix=CHECK_WINDOWSAPP %s
+
+// CHECK_DEFAULT: "-lmsvcrt" "-ladvapi32" "-lshell32" "-luser32" "-lkernel32" "-lmingw32"
+// CHECK_WINDOWSAPP: "-lwindowsapp" "-lmingw32"
+// CHECK_WINDOWSAPP-SAME: "-lmsvcrt" "-lmingw32"