PR tree-optimization/82596 - missing -Warray-bounds on an out-of-bounds
  index into string literal

gcc/ChangeLog:
	* tree.c (array_at_struct_end_p): Handle STRING_CST.

gcc/testsuite/ChangeLog:
	* gcc/testsuite/gcc.dg/pr82596.c: New test.

From-SVN: r253902