diff --git a/libavcodec/x86/constants.h b/libavcodec/x86/constants.h
index b82aef9a47..bbb0ef844a 100644
--- a/libavcodec/x86/constants.h
+++ b/libavcodec/x86/constants.h
@@ -43,6 +43,7 @@ extern const xmm_reg  ff_pw_64;
 extern const uint64_t ff_pw_96;
 extern const uint64_t ff_pw_128;
 extern const ymm_reg  ff_pw_255;
+extern const ymm_reg  ff_pw_256;
 extern const ymm_reg  ff_pw_512;
 extern const ymm_reg  ff_pw_1023;
 extern const ymm_reg  ff_pw_1024;