re PR tree-optimization/16688 (ICE in group_aliases, at tree-ssa-alias.c:1234)

re PR tree-optimization/16688 (ICE in group_aliases, at tree-ssa-alias.c:1234)

	PR tree-optimization/16688
	PR tree-optimization/16689
	* tree-ssa-alias.c (setup_pointers_and_addressables): Remove
	unnecessary initialization of 'tag'.
	(get_tmt_for): Check that the new type tag has the same alias
	set as the pointed-to type.
	(group_aliases): Only regular variables need to be removed
	from the alias set of a name tag.
	* tree-ssa-copy.c (may_propagate_copy): Do not allow copy
	propagation if the two types are not compatible.
	(merge_alias_info): Rename from replace_ssa_names_ann.
	Add more checking.
	(replace_exp_1): If both arguments are SSA_NAMEs, check that
	the propagation can be done.
	Only call merge_alias_info on pointers.
	(propagate_value): Likewise.
	* tree-ssa-copyrename.c: Include langhooks.h.
	(copy_rename_partition_coalesce): Call replace_ssa_name_symbol
	to do the merging.
	Do not coalesce variables with incompatible types.
	(rename_ssa_copies): Call replace_ssa_name_symbol.
	* tree-ssa.c (verify_ssa_name): Verify that the SSA_NAME has
	the same type as the underlying _DECL.
	* tree-ssanames.c (replace_ssa_name_symbol): New function.
	* tree.h (replace_ssa_name_symbol): Declare.

From-SVN: r85108