diff --git a/lib/IDE/CompileInstance.cpp b/lib/IDE/CompileInstance.cpp
index 8e382d19852..3ad8a14bf44 100644
--- a/lib/IDE/CompileInstance.cpp
+++ b/lib/IDE/CompileInstance.cpp
@@ -263,6 +263,11 @@ bool CompileInstance::setupCI(
     return false;
   }
 
+  // Since LLVM arguments are parsed into a global state, LLVM can't handle
+  // multiple argument sets in a process simultaneously. So let's ignore them.
+  // FIXME: Remove this if possible.
+  invocation.getFrontendOptions().LLVMArgs.clear();
+
   /// Declare the frontend to be used for multiple compilations.
   invocation.getFrontendOptions().ReuseFrontendForMutipleCompilations = true;
 
diff --git a/test/SourceKit/Compile/basic.swift b/test/SourceKit/Compile/basic.swift
index f2f780b0a35..b087fdcb74b 100644
--- a/test/SourceKit/Compile/basic.swift
+++ b/test/SourceKit/Compile/basic.swift
@@ -1,5 +1,3 @@
-// REQUIRES: rdar86809003
-
 // RUN: %empty-directory(%t)
 // RUN: %empty-directory(%t/out)
 // RUN: split-file %s %t