[aarch64-port-dev ] RFR(S): 8239914: AArch64: Combine add/sub with comparison against zero

[Nick Gasson]

Hi Pengfei,

On 03/03/20 18:12 pm, Pengfei Li wrote:
> Thanks for reporting this. I just tested the program and found the
> exception also exists with AArch64 JDK master build (without my
> patch).

I couldn't reproduce this on the latest jdk/jdk, only with your patch. I
think the problem is with the cmp*_sub_zero match rules. (a - b) > 0 !==
a > b if a - b overflows because Java requires the result to wrap around
which changes the sign.

>
> Apologize that I will be on leave and unable to create patches in the following days. But I've reported this to my colleagues. I think someone else will reply you soon.

I think it's ok to update the patch when you come back.


Thanks,
Nick