PR middle-end/38343
	* builtins.c (expand_builtin_mempcpy_args): Handle COMPOUND_EXPRs
	potentially returned from folding memcpy.
	(expand_builtin_stpcpy_args): Similarly for folding strcpy.
	(fold_builtin_2): Handle BUILT_IN_STPCPY if result is ignored.

	* gcc.c-torture/compile/pr38343.c: New test.

From-SVN: r142348