diff --git a/src/keyboard.c b/src/keyboard.c
index 0cf7adae741..d2f0cb405f0 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -3647,7 +3647,8 @@ kbd_buffer_unget_event (struct selection_input_event *event)
 #define INPUT_EVENT_POS_MAX \
   ((ptrdiff_t) min (PTRDIFF_MAX, min (TYPE_MAXIMUM (Time) / 2, \
 				      MOST_POSITIVE_FIXNUM)))
-#define INPUT_EVENT_POS_MIN (-1 - INPUT_EVENT_POS_MAX)
+#define INPUT_EVENT_POS_MIN (PTRDIFF_MIN < -INPUT_EVENT_POS_MAX \
+			     ? -1 - INPUT_EVENT_POS_MAX : PTRDIFF_MIN)
 
 /* Return a Time that encodes position POS.  POS must be in range.  */