[aarch64-port-dev ] RFR: 8223020: aarch64: expand minI_rReg and maxI_rReg patterns into separate instructions

[Andrew Haley]

On 4/28/19 2:44 AM, Yangfei (Felix) wrote:

>     JBS: https://bugs.openjdk.java.net/browse/JDK-8223020
>     Webrev: http://cr.openjdk.java.net/~fyang/8223020/webrev.00
> 
>     Currently, two instructions will be emitted for minI_rReg/maxI_rReg patterns: cmpw + cselw. 
>     As these two instructions are always emitted together, the GCM (Global Code Motion) phase will 
>     not be able to schedule them independently.  Patch expands minI_rReg and maxI_rReg patterns
>     into separate instructions.  For the small test case on the JBS, GCM can do a better schedule with
>     this change.  

OK.

I imagine that there are other patterns which might benefit from doing
something similar.

I don't know if you are intending to do more of this kind of change,
but if you are please group them together. It might be worth also
producing a list beforehand and publishing that list here.

-- 
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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