diff --git a/src/x86/regname-x86.c b/src/x86/regname-x86.c
index 8e7f5ca9..fbbcd55c 100644
--- a/src/x86/regname-x86.c
+++ b/src/x86/regname-x86.c
@@ -8,7 +8,7 @@ static const char *regname[] =
 const char *
 unw_regname (unw_regnum_t reg)
 {
-  if (reg < NELEMS (regname))
+  if (reg < (unw_regnum_t) NELEMS (regname))
     return regname[reg];
   else
     return "???";