[AArch64] Rewrite aarch64_simd_valid_immediate

[AArch64] Rewrite aarch64_simd_valid_immediate

This patch reworks aarch64_simd_valid_immediate so that
it's easier to add SVE support.  The main changes are:

- make simd_immediate_info easier to construct
- replace the while (1) { ... break; } blocks with checks that use
  the full 64-bit value of the constant
- treat floating-point modes as integers if they aren't valid
  as floating-point values

2018-01-03  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* config/aarch64/aarch64-protos.h (aarch64_output_simd_mov_immediate):
	Remove the mode argument.
	(aarch64_simd_valid_immediate): Remove the mode and inverse
	arguments.
	* config/aarch64/iterators.md (bitsize): New iterator.
	* config/aarch64/aarch64-simd.md (*aarch64_simd_mov<mode>, and<mode>3)
	(ior<mode>3): Update calls to aarch64_output_simd_mov_immediate.
	* config/aarch64/constraints.md (Do, Db, Dn): Update calls to
	aarch64_simd_valid_immediate.
	* config/aarch64/predicates.md (aarch64_reg_or_orr_imm): Likewise.
	(aarch64_reg_or_bic_imm): Likewise.
	* config/aarch64/aarch64.c (simd_immediate_info): Replace mvn
	with an insn_type enum and msl with a modifier_type enum.
	Replace element_width with a scalar_mode.  Change the shift
	to unsigned int.  Add constructors for scalar_float_mode and
	scalar_int_mode elements.
	(aarch64_vect_float_const_representable_p): Delete.
	(aarch64_can_const_movi_rtx_p)
	(aarch64_simd_scalar_immediate_valid_for_move)
	(aarch64_simd_make_constant): Update call to
	aarch64_simd_valid_immediate.
	(aarch64_advsimd_valid_immediate_hs): New function.
	(aarch64_advsimd_valid_immediate): Likewise.
	(aarch64_simd_valid_immediate): Remove mode and inverse
	arguments.  Rewrite to use the above.  Use const_vec_duplicate_p
	to detect duplicated constants and use aarch64_float_const_zero_rtx_p
	and aarch64_float_const_representable_p on the result.
	(aarch64_output_simd_mov_immediate): Remove mode argument.
	Update call to aarch64_simd_valid_immediate and use of
	simd_immediate_info.
	(aarch64_output_scalar_simd_mov_immediate): Update call
	accordingly.

gcc/testsuite/
	* gcc.target/aarch64/vect-movi.c (movi_float_lsl24): New function.
	(main): Call it.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r256205