* fold-const.c (c_getstr): Clamp STRING_LENGTH to STRING_SIZE.

From-SVN: r264293

gcc/ChangeLog

 2018-09-13  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
+	* fold-const.c (c_getstr): Clamp STRING_LENGTH to STRING_SIZE.
+
 	* varasm.c (compare_constant): Compare type size of STRING_CSTs.
 	(get_constant_size): Don't make STRING_CSTs larger than they are.
 	(check_string_literal): New check function for STRING_CSTs.

gcc/fold-const.c

@@ -14611,6 +14611,10 @@ c_getstr (tree src, unsigned HOST_WIDE_INT *strlen /* = NULL */,
 
   const char *string = TREE_STRING_POINTER (src);
 
+  /* Ideally this would turn into a gcc_checking_assert over time.  */
+  if (string_length > string_size)
+    string_length = string_size;
+
   if (string_length == 0
       || offset >= string_size)
     return NULL;