[ARM][GCC][2/x]: MVE ACLE intrinsics framework patch.

[ARM][GCC][2/x]: MVE ACLE intrinsics framework patch.

This patch is part of MVE ACLE intrinsics framework.
This patches add support to update (read/write) the APSR (Application Program Status Register)
register and FPSCR (Floating-point Status and Control Register) register for MVE.
This patch also enables thumb2 mov RTL patterns for MVE.

A new feature bit vfp_base is added. This bit is enabled for all VFP, MVE and MVE with floating point
extensions. This bit is used to enable the macro TARGET_VFP_BASE. For all the VFP instructions, RTL patterns,
status and control registers are guarded by TARGET_HAVE_FLOAT. But this patch modifies that and the
common instructions, RTL patterns, status and control registers bewteen MVE and VFP are guarded by
TARGET_VFP_BASE macro.

The RTL pattern set_fpscr and get_fpscr are updated to use VFPCC_REGNUM because few MVE intrinsics
set/get carry bit of FPSCR register.

Please refer to Arm reference manual [1] for more details.
[1] https://developer.arm.com/docs/ddi0553/latest

2020-03-16  Andre Vieira  <andre.simoesdiasvieira@arm.com>
	    Mihail Ionescu  <mihail.ionescu@arm.com>
	    Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

	* common/config/arm/arm-common.c (arm_asm_auto_mfpu): When vfp_base
	feature bit is on and -mfpu=auto is passed as compiler option, do not
	generate error on not finding any matching fpu. Because in this case
	fpu is not required.
	* config/arm/arm-cpus.in (vfp_base): Define feature bit, this bit is
	enabled for MVE and also for all VFP extensions.
	(VFPv2): Modify fgroup to enable vfp_base feature bit when ever VFPv2
	is enabled.
	(MVE): Define fgroup to enable feature bits mve, vfp_base and armv7em.
	(MVE_FP): Define fgroup to enable feature bits is fgroup MVE and FPv5
	along with feature bits mve_float.
	(mve): Modify add options in armv8.1-m.main arch for MVE.
	(mve.fp): Modify add options in armv8.1-m.main arch for MVE with
	floating point.
	* config/arm/arm.c (use_return_insn): Replace the
	check with TARGET_VFP_BASE.
	(thumb2_legitimate_index_p): Replace TARGET_HARD_FLOAT with
	TARGET_VFP_BASE.
	(arm_rtx_costs_internal): Replace "TARGET_HARD_FLOAT || TARGET_HAVE_MVE"
	with TARGET_VFP_BASE, to allow cost calculations for copies in MVE as
	well.
	(arm_get_vfp_saved_size): Replace TARGET_HARD_FLOAT with
	TARGET_VFP_BASE, to allow space calculation for VFP registers in MVE
	as well.
	(arm_compute_frame_layout): Likewise.
	(arm_save_coproc_regs): Likewise.
	(arm_fixed_condition_code_regs): Modify to enable using VFPCC_REGNUM
	in MVE as well.
	(arm_hard_regno_mode_ok): Replace "TARGET_HARD_FLOAT || TARGET_HAVE_MVE"
	with equivalent macro TARGET_VFP_BASE.
	(arm_expand_epilogue_apcs_frame): Likewise.
	(arm_expand_epilogue): Likewise.
	(arm_conditional_register_usage): Likewise.
	(arm_declare_function_name): Add check to skip printing .fpu directive
	in assembly file when TARGET_VFP_BASE is enabled and fpu_to_print is
	"softvfp".
	* config/arm/arm.h (TARGET_VFP_BASE): Define.
	* config/arm/arm.md (arch): Add "mve" to arch.
	(eq_attr "arch" "mve"): Enable on TARGET_HAVE_MVE is true.
	(vfp_pop_multiple_with_writeback): Replace "TARGET_HARD_FLOAT
	|| TARGET_HAVE_MVE" with equivalent macro TARGET_VFP_BASE.
	* config/arm/constraints.md (Uf): Define to allow modification to FPCCR
	in MVE.
	* config/arm/thumb2.md (thumb2_movsfcc_soft_insn): Modify target guard
	to not allow for MVE.
	* config/arm/unspecs.md (UNSPEC_GET_FPSCR): Move to volatile unspecs
	enum.
	(VUNSPEC_GET_FPSCR): Define.
	* config/arm/vfp.md (thumb2_movhi_vfp): Add support for VMSR and VMRS
	instructions which move to general-purpose Register from Floating-point
	Special register and vice-versa.
	(thumb2_movhi_fp16): Likewise.
	(thumb2_movsi_vfp): Add support for VMSR and VMRS instructions along
	with MCR and MRC instructions which set and get Floating-point Status
	and Control Register (FPSCR).
	(movdi_vfp): Modify pattern to enable Single-precision scalar float move
	in MVE.
	(thumb2_movdf_vfp): Modify pattern to enable Double-precision scalar
	float move patterns in MVE.
	(thumb2_movsfcc_vfp): Modify pattern to enable single float conditional
	code move patterns of VFP also in MVE by adding TARGET_VFP_BASE check.
	(thumb2_movdfcc_vfp): Modify pattern to enable double float conditional
	code move patterns of VFP also in MVE by adding TARGET_VFP_BASE check.
	(push_multi_vfp): Add support to use VFP VPUSH pattern for MVE by adding
	TARGET_VFP_BASE check.
	(set_fpscr): Add support to set FPSCR register for MVE. Modify pattern
	using VFPCC_REGNUM as few MVE intrinsics use carry bit of FPSCR
	register.
	(get_fpscr): Add support to get FPSCR register for MVE. Modify pattern
		using VFPCC_REGNUM as few MVE intrinsics use carry bit of FPSCR
	register.

2020-03-16  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

	* gcc.target/arm/mve/intrinsics/mve_fp_fpu1.c: New test.
	* gcc.target/arm/mve/intrinsics/mve_fp_fpu2.c: Likewise.
	* gcc.target/arm/mve/intrinsics/mve_fpu1.c: Likewise.
	* gcc.target/arm/mve/intrinsics/mve_fpu2.c: Likewise.
	* gcc.target/arm/mve/intrinsics/mve_fpu3.c: Likewise.