tree-object-size: Dynamic sizes for ADDR_EXPR

tree-object-size: Dynamic sizes for ADDR_EXPR

Allow returning dynamic expressions from ADDR_EXPR for
__builtin_dynamic_object_size and also allow offsets to be dynamic.

gcc/ChangeLog:

	PR middle-end/70090
	* tree-object-size.c (size_valid_p): New function.
	(size_for_offset): Remove OFFSET constness assertion.
	(addr_object_size): Build dynamic expressions for object
	sizes and use size_valid_p to decide if it is valid for the
	given OBJECT_SIZE_TYPE.
	(compute_builtin_object_size): Allow dynamic offsets when
	computing size at O0.
	(call_object_size): Call size_valid_p.
	(plus_stmt_object_size): Allow non-constant offset and use
	size_valid_p to decide if it is valid for the given
	OBJECT_SIZE_TYPE.

gcc/testsuite/ChangeLog:

	PR middle-end/70090
	* gcc.dg/builtin-dynamic-object-size-0.c: Add new tests.
	* gcc.dg/builtin-object-size-1.c (test1)
	[__builtin_object_size]: Adjust expected output for dynamic
	object sizes.
	* gcc.dg/builtin-object-size-2.c (test1)
	[__builtin_object_size]: Likewise.
	* gcc.dg/builtin-object-size-3.c (test1)
	[__builtin_object_size]: Likewise.
	* gcc.dg/builtin-object-size-4.c (test1)
	[__builtin_object_size]: Likewise.

Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org>