diff --git a/clang/lib/Driver/ToolChains/Linux.cpp b/clang/lib/Driver/ToolChains/Linux.cpp
--- a/clang/lib/Driver/ToolChains/Linux.cpp
+++ b/clang/lib/Driver/ToolChains/Linux.cpp
@@ -229,9 +229,11 @@
   // used to target i386.
   // FIXME: This seems unlikely to be Linux-specific.
   ToolChain::path_list &PPaths = getProgramPaths();
-  PPaths.push_back(Twine(GCCInstallation.getParentLibPath() + "/../" +
-                         GCCInstallation.getTriple().str() + "/bin")
-                       .str());
+  if (GCCInstallation.isValid()) {
+    PPaths.push_back(Twine(GCCInstallation.getParentLibPath() + "/../" +
+                           GCCInstallation.getTriple().str() + "/bin")
+                         .str());
+  }
 
   Distro Distro(D.getVFS());