diff --git a/src/compiler/shader_enums.h b/src/compiler/shader_enums.h
index d3446ecc0da14eb8284381b350147fd4e5505dff..0a6ce35357349c2ec0633158cd8a710880e14a01 100644
--- a/src/compiler/shader_enums.h
+++ b/src/compiler/shader_enums.h
@@ -355,6 +355,7 @@ const char *gl_varying_slot_name(gl_varying_slot slot);
 #define SYSTEM_BIT_SAMPLE_POS ((uint64_t)1 << SYSTEM_VALUE_SAMPLE_POS)
 #define SYSTEM_BIT_SAMPLE_MASK_IN ((uint64_t)1 << SYSTEM_VALUE_SAMPLE_MASK_IN)
 #define SYSTEM_BIT_LOCAL_INVOCATION_ID ((uint64_t)1 << SYSTEM_VALUE_LOCAL_INVOCATION_ID)
+#define SYSTEM_BIT_FRONT_FACE ((uint64_t)1 << SYSTEM_VALUE_FRONT_FACE)
 
 /**
  * If the gl_register_file is PROGRAM_SYSTEM_VALUE, the register index will be