diff --git a/sim/testsuite/lib/sim-defs.exp b/sim/testsuite/lib/sim-defs.exp
index 2cf739b3e32..3586fa55076 100644
--- a/sim/testsuite/lib/sim-defs.exp
+++ b/sim/testsuite/lib/sim-defs.exp
@@ -142,6 +142,7 @@ proc sim_init_toolchain {} {
     } {
 	verbose -log "Can't execute C compiler"
 	set global_cc_works 0
+	set global_cc_os ""
     }
 
     file delete $objdir/compilercheck.x