* rtl.h (STRING_POOL_ADDRESS_P): Rename to DEFERRED_CONSTANT_P.
	* varasm.c (struct varasm_status): Add deferred_constants field.
	(n_deferred_strings): Delete variable.
	(n_deferred_constants): New #define.
	(struct constant_descriptor_tree): Kill next and label fields.
	(const_hash_table, MAX_HASH_TABLE): Delete.
	(const_desc_htab): New static variable.
	(const_hash): Rename const_desc_hash, and make it fit the
	hashtab.h interface.
	(const_desc_eq): New.
	(const_hash_1, compare_constant): Const-ify arguments.
	(build_constant_desc): Set DEFERRED_CONSTANT_P on all new
	SYMBOL_REFs.  Clarify comments.  Don't set desc->label.
	(output_constant_def): Do the lookup/insert using the
	hashtab.h interface.  Don't muck with n_deferred_constants or
	DEFERRED_CONSTANT_P here.
	Always call maybe_output_constant_def_contents.
	(maybe_output_constant_def_contents): Take a pointer to the
	descriptor, not the EXP and RTL separately.  Return
	immediately if this constant is not deferred.  Defer output of
	everything, except writable string constants.  Update
	n_deferred_constants here.
	(output_constant_def_contents): Now takes just one argument,
	an rtx.  Clear DEFERRED_CONSTANT_P here.
	(mark_constant_pool): Update for rename of n_deferred_strings.
	(mark_constant): Don't clear DEFERRED_CONSTANT_P here.

	(init_varasm_status): Clear p->deferred_constants.
	(init_varasm_once): Call htab_create_ggc for const_desc_htab.

	* gcc.dg/const-elim-1.c, gcc.dg/const-elim-2.c: New testcases.

From-SVN: r66505