diff --git a/sha1_file.c b/sha1_file.c
index 423ec64e87..7b2612f733 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -3178,17 +3178,22 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st,
 	     enum object_type type, const char *path, unsigned flags)
 {
 	int ret;
-	size_t size = xsize_t(st->st_size);
 
+	/*
+	 * Call xsize_t() only when needed to avoid potentially unnecessary
+	 * die() for large files.
+	 */
 	if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
 		ret = index_stream_convert_blob(sha1, fd, path, flags);
 	else if (!S_ISREG(st->st_mode))
 		ret = index_pipe(sha1, fd, type, path, flags);
-	else if (size <= big_file_threshold || type != OBJ_BLOB ||
+	else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
 		 (path && would_convert_to_git(path)))
-		ret = index_core(sha1, fd, size, type, path, flags);
+		ret = index_core(sha1, fd, xsize_t(st->st_size), type, path,
+				 flags);
 	else
-		ret = index_stream(sha1, fd, size, type, path, flags);
+		ret = index_stream(sha1, fd, xsize_t(st->st_size), type, path,
+				   flags);
 	close(fd);
 	return ret;
 }