Re: [Qemu-devel] [PATCH v3 1/1] target-arm: Use Neon for zero checking

[Peter Maydell]

On 5 July 2016 at 13:24, Vijay Kilari <address@hidden> wrote:
> On Sat, Jul 2, 2016 at 3:37 AM, Richard Henderson <address@hidden> wrote:
>> Consider
>>
>> #define VECTYPE        uint32x4_t
>> #define ALL_EQ(v1, v2) (vmaxvq_u32((v1) ^ (v2)) == 0)
>>
>>
>> which compiles down to
>>
>>   1c:   6e211c00        eor     v0.16b, v0.16b, v1.16b
>>   20:   6eb0a800        umaxv   s0, v0.4s
>>   24:   1e260000        fmov    w0, s0
>>   28:   6b1f001f        cmp     w0, wzr
>>   2c:   1a9f17e0        cset    w0, eq
>>   30:   d65f03c0        ret
>
> For me this code compiles as below and migration time is ~100ms more.

Thanks for benchmarking this. I'll take your original patch into
target-arm.next.

-- PMM