re PR middle-end/80423 (GC related -fcompare-debug failure)

re PR middle-end/80423 (GC related -fcompare-debug failure)

	PR middle-end/80423
	* tree.h (build_array_type): Add typeless_storage default argument.
	* tree.c (type_cache_hasher::equal): Also compare
	TYPE_TYPELESS_STORAGE flag for ARRAY_TYPEs.
	(build_array_type): Add typeless_storage argument, set
	TYPE_TYPELESS_STORAGE to it, if shared also hash it, and pass to
	recursive call.
	(build_nonshared_array_type): Adjust build_array_type_1 caller.
	(build_array_type): Likewise.  Add typeless_storage argument.
c-family/
	* c-common.c (complete_array_type): Preserve TYPE_TYPELESS_STORAGE.
cp/
	* tree.c (build_cplus_array_type): Call build_array_type
	with the intended TYPE_TYPELESS_STORAGE flag value, instead
	of calling build_array_type and modifying later TYPE_TYPELESS_STORAGE
	on the shared type.
testsuite/
	* g++.dg/other/pr80423.C: New test.

From-SVN: r247014