aarch64: Improve register allocation for lane instructions

REG_ALLOC_ORDER is much less important than it used to be, but it
is still used as a tie-breaker when multiple registers in a class
are equally good.

Previously aarch64 used the default approach of allocating in order
of increasing register number.  But as the comment in the patch says,
it's better to allocate FP and predicate registers in the opposite
order, so that we don't eat into smaller register classes unnecessarily.

This fixes some existing FIXMEs and improves the register allocation
for some Arm ACLE code.

Doing this also showed that *vcond_mask_<mode><vpred> (predicated MOV/SEL)
unnecessarily required p0-p7 rather than p0-p15 for the unpredicated
movprfx alternatives.  Only the predicated movprfx alternative requires
p0-p7 (due to the movprfx itself, rather than due to the main instruction).

gcc/
	* config/aarch64/aarch64-protos.h (aarch64_adjust_reg_alloc_order):
	Declare.
	* config/aarch64/aarch64.h (REG_ALLOC_ORDER): Define.
	(ADJUST_REG_ALLOC_ORDER): Likewise.
	* config/aarch64/aarch64.cc (aarch64_adjust_reg_alloc_order): New
	function.
	* config/aarch64/aarch64-sve.md (*vcond_mask_<mode><vpred>): Use
	Upa rather than Upl for unpredicated movprfx alternatives.

gcc/testsuite/
	* gcc.target/aarch64/sve/acle/asm/abd_f16.c: Remove XFAILs.
	* gcc.target/aarch64/sve/acle/asm/abd_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/abd_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/abd_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/abd_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/abd_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/abd_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/abd_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/abd_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/abd_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/abd_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/add_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/add_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/add_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/add_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/add_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/add_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/add_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/add_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/and_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/and_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/and_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/and_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/and_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/and_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/and_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/and_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/asr_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/asr_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/bic_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/bic_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/bic_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/bic_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/bic_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/bic_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/bic_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/bic_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/div_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/div_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/div_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/div_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/div_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/div_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/div_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/divr_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/divr_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/divr_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/divr_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/divr_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/divr_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/divr_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/dot_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/dot_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/dot_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/dot_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/eor_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/eor_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/eor_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/eor_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/eor_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/eor_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/eor_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/eor_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_wide_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_wide_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_wide_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_wide_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_wide_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsl_wide_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsr_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/lsr_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mad_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mad_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mad_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mad_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mad_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mad_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mad_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mad_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mad_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mad_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mad_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/max_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/max_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/max_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/max_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/max_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/max_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/max_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/max_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/min_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/min_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/min_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/min_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/min_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/min_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/min_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/min_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mla_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mla_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mla_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mla_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mla_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mla_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mla_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mla_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mla_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mla_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mla_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mls_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mls_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mls_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mls_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mls_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mls_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mls_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mls_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mls_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mls_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mls_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/msb_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/msb_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/msb_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/msb_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/msb_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/msb_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/msb_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/msb_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/msb_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/msb_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/msb_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_f16_notrap.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_f32_notrap.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_f64_notrap.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mul_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mulh_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mulh_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mulh_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mulh_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mulh_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mulh_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mulh_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mulh_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mulx_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mulx_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/mulx_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/nmad_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/nmad_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/nmad_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/nmla_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/nmla_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/nmla_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/nmls_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/nmls_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/nmls_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/nmsb_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/nmsb_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/nmsb_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/orr_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/orr_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/orr_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/orr_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/orr_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/orr_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/orr_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/orr_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/scale_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/scale_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/scale_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/sub_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/sub_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/sub_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/sub_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/sub_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/sub_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/sub_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/sub_u8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_f16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_f16_notrap.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_f32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_f32_notrap.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_f64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_f64_notrap.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_s16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_s32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_s64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_s8.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_u16.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_u32.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_u64.c: Likewise.
	* gcc.target/aarch64/sve/acle/asm/subr_u8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/bcax_s16.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/bcax_s32.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/bcax_s64.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/bcax_s8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/bcax_u16.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/bcax_u32.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/bcax_u64.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/bcax_u8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qadd_s16.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qadd_s32.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qadd_s64.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qadd_s8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qadd_u16.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qadd_u32.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qadd_u64.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qadd_u8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qdmlalb_s16.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qdmlalb_s32.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qdmlalb_s64.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qdmlalbt_s16.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qdmlalbt_s32.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qdmlalbt_s64.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsub_s16.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsub_s32.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsub_s64.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsub_s8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsub_u16.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsub_u32.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsub_u64.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsub_u8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsubr_s16.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsubr_s32.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsubr_s64.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsubr_s8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsubr_u16.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsubr_u32.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsubr_u64.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/qsubr_u8.c: Likewise.