constraints.md ("S"): Match r0rel_constant_p too.

constraints.md ("S"): Match r0rel_constant_p too.

2017-10-26  Sandra Loosemore  <sandra@codesourcery.com>

	gcc/
	* config/nios2/constraints.md ("S"): Match r0rel_constant_p too.
	* config/nios2/nios2-protos.h (r0rel_constant_p): Declare.
	* config/nios2/nios2.c: (nios2_r0rel_sec_regex): New.
	(nios2_option_overide): Initialize it.  Don't allow R0-relative
	addressing with PIC.
	(nios2_rtx_costs): Handle r0rel_constant_p like gprel_constant_p.
	(nios2_symbolic_constant_p): Likewise.
	(nios2_legitimate_address_p): Likewise.
	(nios2_r0rel_section_name_p): New.
	(nios2_symbol_ref_in_r0rel_data_p): New.
	(nios2_emit_move_sequence): Handle r0rel_constant_p.
	(r0rel_constant_p): New.
	(nios2_print_operand_address): Handle r0rel_constant_p.
	(nios2_cdx_narrow_form_p): Likewise.
	* config/nios2/nios2.opt (mr0rel-sec=): New option.
	* doc/invoke.texi (Option Summary): Add -mr0rel-sec.
	(Nios II Options): Document -mr0rel-sec.

	gcc/testsuite/
	* gcc.target/nios2/gpopt-r0rel-sec.c: New.

From-SVN: r254124