PR c++/67913 - new expression with negative size not diagnosed

PR c++/67913 - new expression with negative size not diagnosed
PR c++/67927 - array new expression with excessive number of elements
               not diagnosed

gcc/cp/
	* call.c (build_operator_new_call): Do not assume size_check
	is non-null, analogously to the top half of the function.
	* init.c (build_new_1): Detect and diagnose array sizes in
	excess of the maximum of roughly SIZE_MAX / 2.
	Insert a runtime check only for arrays with a non-constant size.
	(build_new): Detect and diagnose negative array sizes.

gcc/testsuite/
	* init/new45.C: New test to verify that operator new is invoked
	with or without overhead for a cookie.
	* init/new44.C: New test for placement new expressions for arrays
	with excessive number of elements.
	* init/new43.C: New test for placement new expressions for arrays
	with negative number of elements.
	* other/new-size-type.C: Expect array new expression with
	an excessive number of elements to be rejected.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@230081 138bc75d-0d04-0410-961f-82ee72b054a4