diff --git a/libguile/vm-engine.h b/libguile/vm-engine.h
index 5a4bf40f3..0526f88c3 100644
--- a/libguile/vm-engine.h
+++ b/libguile/vm-engine.h
@@ -98,6 +98,18 @@
 #define JT_REG
 #endif
 
+
+/*
+ * As of "gcc version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build
+ * 2336.1.00)" it appears that llvm-gcc doesn't handle labels-as-values
+ * as efficiently as the basic switch statement, so we want to switch
+ * them off.
+ *
+ * (See also vm-expand.h.)
+ */
+#ifdef __llvm__
+# undef HAVE_LABELS_AS_VALUES
+#endif
 
 /*
  * Cache/Sync
diff --git a/libguile/vm-expand.h b/libguile/vm-expand.h
index a0427efc3..2e9fea2c9 100644
--- a/libguile/vm-expand.h
+++ b/libguile/vm-expand.h
@@ -16,6 +16,18 @@
  * 02110-1301 USA
  */
 
+/*
+ * As of "gcc version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build
+ * 2336.1.00)" it appears that llvm-gcc doesn't handle labels-as-values
+ * as efficiently as the basic switch statement, so we want to switch
+ * them off.
+ *
+ * (See also vm-engine.h.)
+ */
+#ifdef __llvm__
+# undef HAVE_LABELS_AS_VALUES
+#endif
+
 #ifndef VM_LABEL
 #define VM_LABEL(tag) l_##tag
 #define VM_OPCODE(tag) scm_op_##tag