--- avr-gcc-6.3.0/gcc-6.3.0/gcc/ubsan.c 2016-12-07 23:39:29.000000000 +0100
+++ avr-gcc-6.3.0/gcc-6.3.0/gcc/ubsan.c 2017-03-08 18:35:56.000000000 +0100
@@ -1471,7 +1486,7 @@ ubsan_use_new_style_p (location_t loc)
expanded_location xloc = expand_location (loc);
if (xloc.file == NULL || strncmp (xloc.file, "\1", 2) == 0
- || xloc.file == '\0' || xloc.file[0] == '\xff'
+ || xloc.file[0] == '\0' || xloc.file[0] == '\xff'
|| xloc.file[1] == '\xff')
return false;