[Patch, ARM] Relax the restrictions on REG_SP under Thumb mode on ARMv8-A

[Nick Clifton]

Hi Jiong,

> gas/
> 2017-05-25  Jiong Wang  <jiong.wang@arm.com>
> 
>          * config/tc-arm.c (reject_bad_reg): Allow REG_SP on ARMv8-A.
>          (parse_operands): Allow REG_SP for OP_oRRnpcsp and OP_RRnpcsp on
>          ARMv8-A.
>          (do_co_reg): Allow REG_SP for Rd on ARMv8-A.
>          (do_t_add_sub): Likewise.
>          (do_t_mov_cmp): Likewise.
>          (do_t_tb): Likewise.
>          * testsuite/gas/arm/ld-sp-warn.l: Delete the warning on REG_SP as Rt for
>          ldrsb.
>          * testsuite/gas/arm/sp-pc-validations-bad-t-v8a.d: New test.
>          * testsuite/gas/arm/sp-pc-validations-bad-t-v8a.l: New test.
>          * testsuite/gas/arm/sp-pc-validations-bad-t.d: Specifies -march=armv7-a.
>          * testsuite/gas/arm/sp-pc-validations-bad-t.s: Remove ".arch armv7-a".
>          * testsuite/gas/arm/sp-usage-thumb2-relax-on-v7.d: New test.
>          * testsuite/gas/arm/sp-usage-thumb2-relax-on-v7.l: New test.
>          * testsuite/gas/arm/sp-usage-thumb2-relax-on-v8.d: New test.
>          * testsuite/gas/arm/sp-usage-thumb2-relax.s: New test.
>          * testsuite/gas/arm/strex-bad-t.d: Specifies -march=armv7-a.

Approved - please apply.

Cheers
  Nick