PR tree-optimization/47679
	* tree-ssa-dom.c (enum expr_kind): Moved from here to
	tree-ssa-scopedtables.h.
	(struct hashable_expr, class expr_hash_elt): Likewise.
	(struct expr_elt_hasher, class avail_exprs_stack): Likewise.
	Move associated methods into tree-ssa-scopedtables.c.
	(avail_expr_hash, initialize_expr_from_cond): Similarly.
	(hashable_expr_equal_p, add_expr_commutative): Likewise.
	(add_hashable_expr): Likewise.
	(record_cond): Delete element directly.
	* tree-ssa-scopedtables.h (avail_expr_stack, const_and_copies): Add
	private copy ctor and assignment operator methods.
	(expr_elt_hasher): Inline trivial methods.
	(initialize_expr_from_cond): Prototype.
	* tree-ssa-scopedtables.c: Add necessary includes, functions and
	methods that were previously in tree-ssa-dom.c.  Improve various
	comments.

From-SVN: r227831