diff --git a/av1/common/enums.h b/av1/common/enums.h
index 0cce8f0ee46191de2cd1182bc8ba05caa9cb3e36..3f905deaa435a35dc98c1a0b574f11a117df6001 100644
--- a/av1/common/enums.h
+++ b/av1/common/enums.h
@@ -318,6 +318,8 @@ typedef enum {
 } PALETTE_COLOR;
 #endif  // CONFIG_PALETTE
 
+// Note: All directional predictors must be between V_PRED and D63_PRED (both
+// inclusive).
 typedef enum ATTRIBUTE_PACKED {
   DC_PRED,    // Average of above and left pixels
   V_PRED,     // Vertical
diff --git a/av1/common/reconintra.h b/av1/common/reconintra.h
index fbcb7f9b47b95adf66fa2366b56a4f5b8074a930..8ad3bae8d0dd3094d7e70cbec994a7bbe6525919 100644
--- a/av1/common/reconintra.h
+++ b/av1/common/reconintra.h
@@ -76,14 +76,7 @@ static const INTERINTRA_MODE intra_to_interintra_mode[INTRA_MODES] = {
 #if CONFIG_EXT_INTRA
 static INLINE int av1_is_directional_mode(PREDICTION_MODE mode,
                                           BLOCK_SIZE bsize) {
-  return mode != DC_PRED && mode != TM_PRED &&
-#if CONFIG_ALT_INTRA
-         mode != SMOOTH_PRED &&
-#if CONFIG_SMOOTH_HV
-         mode != SMOOTH_V_PRED && mode != SMOOTH_H_PRED &&
-#endif  // CONFIG_SMOOTH_HV
-#endif  // CONFIG_ALT_INTRA
-         bsize >= BLOCK_8X8;
+  return mode >= V_PRED && mode <= D63_PRED && bsize >= BLOCK_8X8;
 }
 #endif  // CONFIG_EXT_INTRA