diff --git a/gcc/lto/ChangeLog b/gcc/lto/ChangeLog
index 62fec498380..55013a81bb2 100644
--- a/gcc/lto/ChangeLog
+++ b/gcc/lto/ChangeLog
@@ -1,3 +1,7 @@
+2018-02-08  Jan Hubicka  <hubicka@ucw.cz>
+
+	* lto-partition.c (lto_balanced_map): Watch overflow.
+
 2018-02-08  Jan Hubicka  <hubicka@ucw.cz>
 
 	PR ipa/81360
diff --git a/gcc/lto/lto-partition.c b/gcc/lto/lto-partition.c
index 6055dad99b5..60daafdf375 100644
--- a/gcc/lto/lto-partition.c
+++ b/gcc/lto/lto-partition.c
@@ -757,7 +757,8 @@ lto_balanced_map (int n_lto_partitions, int max_partition_size)
 	  if (npartitions < n_lto_partitions)
 	    partition_size = total_size / (n_lto_partitions - npartitions);
 	  else
-	    partition_size = INT_MAX;
+	    /* Watch for overflow.  */
+	    partition_size = INT_MAX / 16;
 
 	  if (partition_size < PARAM_VALUE (MIN_PARTITION_SIZE))
 	    partition_size = PARAM_VALUE (MIN_PARTITION_SIZE);