gcc/

	* gimple-ssa-strength-reduction.c: Include tree-affine.h.
	(name_expansions): New static variable.
	(alt_base_map): Ditto.
	(get_alternative_base): New function.
	(find_basis_for_candidate): For CAND_REF, optionally call
	find_basis_for_base_expr with the returned value from
	get_alternative_base.
	(record_potential_basis): Add new parameter 'base' of type 'tree';
	add an assertion of non-NULL base; use base to set node->base_expr.
	(alloc_cand_and_find_basis): Update; call record_potential_basis
	for CAND_REF with the returned value from get_alternative_base.
	(replace_refs): Dump details on the replacing.
	(execute_strength_reduction): Call pointer_map_create for
	alt_base_map; call free_affine_expand_cache with &name_expansions.

gcc/testsuite/

	* gcc.dg/tree-ssa/slsr-39.c: Update.
	* gcc.dg/tree-ssa/slsr-41.c: New test.

From-SVN: r205655