diff --git a/src/liboslexec/runtimeoptimize.cpp b/src/liboslexec/runtimeoptimize.cpp
index 7baf6ba34..ca8c8f6b2 100644
--- a/src/liboslexec/runtimeoptimize.cpp
+++ b/src/liboslexec/runtimeoptimize.cpp
@@ -3348,8 +3348,7 @@ RuntimeOptimizer::run()
                     m_unknown_closures_needed = true;
                 }
             } else if (op.opname() == u_backfacing) {
-                m_globals_needed.insert(u_N);
-                m_globals_needed.insert(u_I);
+                m_globals_needed.insert(u_backfacing);
             } else if (op.opname() == u_calculatenormal) {
                 m_globals_needed.insert(u_flipHandedness);
             } else if (op.opname() == u_getattribute) {
diff --git a/testsuite/globals-needed/ref/out.txt b/testsuite/globals-needed/ref/out.txt
index 344f7646b..234cbe3d8 100644
--- a/testsuite/globals-needed/ref/out.txt
+++ b/testsuite/globals-needed/ref/out.txt
@@ -1,2 +1,2 @@
-Need 2 globals:  I N
+Need 1 globals:  backfacing
 Need 2 globals:  P flipHandedness