diff --git a/src/hb-aat-layout.h b/src/hb-aat-layout.h
index 760aaae40..b617e8b70 100644
--- a/src/hb-aat-layout.h
+++ b/src/hb-aat-layout.h
@@ -85,7 +85,7 @@ typedef enum
   HB_AAT_LAYOUT_FEATURE_TYPE_LANGUAGE_TAG_TYPE			= 39,
   HB_AAT_LAYOUT_FEATURE_TYPE_CJK_ROMAN_SPACING_TYPE		= 103,
 
-  _HB_AAT_LAYOUT_FEATURE_TYPE_MAX_VALUE= 0x7FFFFFFFu, /*< skip >*/
+  _HB_AAT_LAYOUT_FEATURE_TYPE_MAX_VALUE = HB_TAG_MAX_SIGNED /*< skip >*/
 } hb_aat_layout_feature_type_t;
 
 /**
@@ -424,7 +424,7 @@ typedef enum
   HB_AAT_LAYOUT_FEATURE_SELECTOR_DEFAULT_CJK_ROMAN		= 2,
   HB_AAT_LAYOUT_FEATURE_SELECTOR_FULL_WIDTH_CJK_ROMAN		= 3,
 
-  _HB_AAT_LAYOUT_FEATURE_SELECTOR_MAX_VALUE= 0x7FFFFFFFu, /*< skip >*/
+  _HB_AAT_LAYOUT_FEATURE_SELECTOR_MAX_VALUE = HB_TAG_MAX_SIGNED /*< skip >*/
 } hb_aat_layout_feature_selector_t;
 
 HB_EXTERN unsigned int
diff --git a/src/hb-ot-var.h b/src/hb-ot-var.h
index cf6f0c950..df89bc5a2 100644
--- a/src/hb-ot-var.h
+++ b/src/hb-ot-var.h
@@ -68,7 +68,7 @@ hb_ot_var_get_axis_count (hb_face_t *face);
 typedef enum { /*< flags >*/
   HB_OT_VAR_AXIS_FLAG_HIDDEN	= 0x00000001u,
 
-  _HB_OT_VAR_AXIS_FLAG_MAX_VALUE= 0x7FFFFFFFu /*< skip >*/
+  _HB_OT_VAR_AXIS_FLAG_MAX_VALUE= HB_TAG_MAX_SIGNED /*< skip >*/
 } hb_ot_var_axis_flags_t;
 
 /**