Emit landing pads for SEH even if nounwind is present

Disabling exceptions applies nounwind to lots of functions. SEH catches
asynch exceptions, so emit the landing pad anyway.

llvm-svn: 228769
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index f6e2bae..998e067 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -1122,6 +1122,11 @@
     return getInvokeDestImpl();
   }
 
+  bool currentFunctionUsesSEHTry() const {
+    const auto *FD = dyn_cast_or_null<FunctionDecl>(CurCodeDecl);
+    return FD && FD->usesSEHTry();
+  }
+
   const TargetInfo &getTarget() const { return Target; }
   llvm::LLVMContext &getLLVMContext() { return CGM.getLLVMContext(); }