[aarch64-port-dev ] RFR(XS): 8247979: aarch64: missing side effect of killing flags for clearArray_reg_reg

[Yangfei (Felix)]

Hi Andrew,

> -----Original Message-----
> From: Andrew Dinn [mailto:adinn at redhat.com]
> Sent: Tuesday, June 23, 2020 5:37 PM
> To: Yangfei (Felix) <felix.yang at huawei.com>; hotspot-compiler-
> dev at openjdk.java.net
> Cc: aarch64-port-dev at openjdk.java.net
> Subject: Re: RFR(XS): 8247979: aarch64: missing side effect of killing flags for
> clearArray_reg_reg
> 
> On 23/06/2020 01:42, Yangfei (Felix) wrote:
> >     Bug: https://bugs.openjdk.java.net/browse/JDK-8247979
> >     Webrev: http://cr.openjdk.java.net/~fyang/8247979/webrev.00
> >
> >     For clearArray_reg_reg in aarch64.ad, we call function:
> MacroAssembler::zero words(Register ptr, Register cnt).
> >     This function modifies the flags register by doing a cmp instruction at
> entry.  But this is not reflected on the side effect of clearArray_reg_reg.
> >     We didn't see this is triggering problems.  But this may pose similar risk as
> bug: 8224828: aarch64: rflags is not correct after safepoint poll.
> >     Tier1-3 tested on aarch64-linux-gnu.  OK?
> Nice catch, Felix. The patch looks good to me.

Thanks for the fast review. 
Pushed as: http://hg.openjdk.java.net/jdk/jdk/rev/9fce19fdda7e

Felix