diff --git a/libavutil/x86_cpu.h b/libavutil/x86_cpu.h
index 8fd5f8600e..548fe42ec6 100644
--- a/libavutil/x86_cpu.h
+++ b/libavutil/x86_cpu.h
@@ -15,6 +15,7 @@
 #  define REGBP   rbp
 #  define REGa    rax
 #  define REGb    rbx
+#  define REGc    rcx
 #  define REGSP   rsp
 
 #else
@@ -32,6 +33,7 @@
 #  define REGBP   ebp
 #  define REGa    eax
 #  define REGb    ebx
+#  define REGc    ecx
 #  define REGSP   esp
 #endif