Enable LRA for MIPS

Enable LRA for MIPS

gcc/

	* config/mips/constraints.md ("d"): BASE_REG_CLASS replaced by
	"TARGET_MIPS16 ? M16_REGS : GR_REGS".
	* config/mips/mips.c (mips_regno_to_class): Update for M16_SP_REGS.
	(mips_regno_mode_ok_for_base_p): Remove use of !strict_p for MIPS16.
	(mips_register_priority): New function that implements the target
	hook TARGET_REGISTER_PRIORITY.
	(mips_spill_class): Likewise for TARGET_SPILL_CLASS.
	(mips_lra_p): Likewise for TARGET_LRA_P.
	(TARGET_REGISTER_PRIORITY): Define macro.
	(TARGET_SPILL_CLASS): Likewise.
	(TARGET_LRA_P): Likewise.
	* config/mips/mips.h (reg_class): Add M16_SP_REGS and SPILL_REGS
	classes.
	(REG_CLASS_NAMES): Likewise.
	(REG_CLASS_CONTENTS): Likewise.
	(BASE_REG_CLASS): Use M16_SP_REGS.
	* config/mips/mips.md (*mul_acc_si): Add alternative tuned for LRA.
	New set attribute to enable alternatives depending on the register
	allocator used.
	(*mul_acc_si_r3900, *mul_sub_si): Likewise.
	(*lea64): Disable pattern for MIPS16.
	* config/mips/mips.opt (mlra): New option.

From-SVN: r211805