MSP430: Simplify and extend shift instruction patterns

MSP430: Simplify and extend shift instruction patterns

The implementation of define_expand and define_insn patterns to handle
shifts in the MSP430 backend is inconsistent, resulting in missed
opportunities to make best use of the architecture's features.

There's now a single define_expand used as the entry point for all valid
shifts, and the decision to either use a helper function to perform the
shift (often required for the 430 ISA), or fall through to the
define_insn patterns can be made from that expander function.

Shifts by a constant amount have been grouped into one define_insn for
each type of shift, instead of having different define_insn patterns for
shifts by different amounts.

A new target option "-mmax-inline-shift=" has been added to allow tuning
of the number of shift instructions to emit inline, instead of using
a library helper function.

gcc/ChangeLog:

	* config/msp430/constraints.md (K): Change unused constraint to
	constraint to a const_int between 1 and 19.
	(P): New constraint.
	* config/msp430/msp430-protos.h (msp430x_logical_shift_right): Remove.
	(msp430_expand_shift): New.
	(msp430_output_asm_shift_insns): New.
	* config/msp430/msp430.c (msp430_rtx_costs): Remove shift costs.
	(CSH): Remove.
	(msp430_expand_helper): Remove hard-coded generation of some inline
	shift insns.
	(use_helper_for_const_shift): New.
	(msp430_expand_shift): New.
	(msp430_output_asm_shift_insns): New.
	(msp430_print_operand): Add new 'W' operand selector.
	(msp430x_logical_shift_right): Remove.
	* config/msp430/msp430.md (HPSI): New define_mode_iterator.
	(HDI): Likewise.
	(any_shift): New define_code_iterator.
	(shift_insn): New define_code_attr.
	Adjust unnamed insn patterns searched for by combine.
	(ashlhi3): Remove.
	(slli_1): Remove.
	(430x_shift_left): Remove.
	(slll_1): Remove.
	(slll_2): Remove.
	(ashlsi3): Remove.
	(ashldi3): Remove.
	(ashrhi3): Remove.
	(srai_1): Remove.
	(430x_arithmetic_shift_right): Remove.
	(srap_1): Remove.
	(srap_2): Remove.
	(sral_1): Remove.
	(sral_2): Remove.
	(ashrsi3): Remove.
	(ashrdi3): Remove.
	(lshrhi3): Remove.
	(srli_1): Remove.
	(430x_logical_shift_right): Remove.
	(srlp_1): Remove.
	(srll_1): Remove.
	(srll_2x): Remove.
	(lshrsi3): Remove.
	(lshrdi3): Remove.
	(<shift_insn><mode>3): New define_expand.
	(<shift_insn>hi3_430): New define_insn.
	(<shift_insn>si3_const): Likewise.
	(ashl<mode>3_430x): Likewise.
	(ashr<mode>3_430x): Likewise.
	(lshr<mode>3_430x): Likewise.
	(*bitbranch<mode>4_z): Replace renamed predicate msp430_bitpos with
	const_0_to_15_operand.
	* config/msp430/msp430.opt: New option -mmax-inline-shift=.
	* config/msp430/predicates.md (const_1_to_8_operand): New predicate.
	(const_0_to_15_operand): Rename msp430_bitpos predicate.
	(const_1_to_19_operand): New predicate.
	* doc/invoke.texi: Document -mmax-inline-shift=.

libgcc/ChangeLog:

	* config/msp430/slli.S (__gnu_mspabi_sllp): New.
	* config/msp430/srai.S (__gnu_mspabi_srap): New.
	* config/msp430/srli.S (__gnu_mspabi_srlp): New.

gcc/testsuite/ChangeLog:

	* gcc.target/msp430/emulate-srli.c: Fix expected assembler text.
	* gcc.target/msp430/max-inline-shift-430-no-opt.c: New test.
	* gcc.target/msp430/max-inline-shift-430.c: New test.
	* gcc.target/msp430/max-inline-shift-430x.c: New test.