[PATCH] arm: Fix MVE vmlas encoding

[Richard Earnshaw (foss)]

On 13/01/2026 11:43, richard.ball@arm.com wrote:
> From: Richard Ball <Richard.Ball@arm.com>
> 
> Continuation of fix to VMLA
> 
> Bit 12 of the first halfword in the VMLAS instruction is listed as (0)
> in the ARMARM (document DDI0553B.w, version ID07072023).
> This means that the instruction does not discriminate between signed
> and unsigned types and processing elements do not use the bit.
> The encoding used by gas was based on an older version
> of the document that made the sign important.
> This change makes it possible to use vmlas.i8 (16,32) in addition to
> vmlas.u8 and vmlas.s8 mnemonics, with the i8, i16 and i32 aliases becoming
> the default when disassembling.
> The generated encoding sets bit 12 to 0, compatibly with other
> assembler implementations.
> ---
>  gas/config/tc-arm.c               |    4 +-
>  gas/testsuite/gas/arm/mve-vmlas.d | 3383 +++++++++++++++++------------
>  gas/testsuite/gas/arm/mve-vmlas.s |    8 +-
>  opcodes/arm-dis.c                 |    2 +-
>  4 files changed, 2041 insertions(+), 1356 deletions(-)

OK

R.