re PR target/48032 (PowerPC64 -mcmodel=medium invalid ld offset)

re PR target/48032 (PowerPC64 -mcmodel=medium invalid ld offset)

	PR target/48032
	* config/rs6000/rs6000.c (offsettable_ok_by_alignment): Do not
	presume symbol_refs without a symbol_ref_decl are suitably
	aligned, nor other trees we may see here.  Handle anchor symbols.
	(legitimate_constant_pool_address_p): Comment.  Add mode param.
	Check cmodel=medium addresses.  Adjust all calls.
	(rs6000_emit_move): Don't call offsettable_ok_by_alignment on
	creating cmodel=medium optimized access to locals.
	* config/rs6000/constraints.md (R): Pass QImode to
	legitimate_constant_pool_address_p.
	* config/rs6000/predicates.md (input_operand): Pass mode to
	legitimate_constant_pool_address_p.
	* config/rs6000/rs6000-protos.h (legitimate_constant_pool_address_p):
	Update prototype.

From-SVN: r170976