diff --git a/libswscale/x86/yuv2rgb_template.c b/libswscale/x86/yuv2rgb_template.c
index b3225a4a53..2ff97e22e1 100644
--- a/libswscale/x86/yuv2rgb_template.c
+++ b/libswscale/x86/yuv2rgb_template.c
@@ -140,8 +140,10 @@
     "js   1b\n\t"                                \
 
 #if COMPILE_TEMPLATE_MMXEXT
+#undef RGB_PACK24_B_OPERANDS
 #define RGB_PACK24_B_OPERANDS NAMED_CONSTRAINTS_ADD(mask1101,mask0110,mask0100,mask0010,mask1001)
 #else
+#undef RGB_PACK24_B_OPERANDS
 #define RGB_PACK24_B_OPERANDS
 #endif