diff --git a/lib/libc/regex/grot/debug.c b/lib/libc/regex/grot/debug.c
index caa2ca39612..af8e4f5a1d7 100644
--- a/lib/libc/regex/grot/debug.c
+++ b/lib/libc/regex/grot/debug.c
@@ -186,7 +186,7 @@ FILE *d;
 			fprintf(d, ">");
 			break;
 		default:
-			fprintf(d, "!%d(%d)!", OP(*s), opnd);
+			fprintf(d, "!%ld(%ld)!", OP(*s), (long)opnd);
 			break;
 		}
 		if (!done)