[PING] RE: RFR(S): 8210152: Optimize integer divisible by power-of-2 check

[Pengfei Li (Arm Technology China)]

Hi,

I've updated the patch based on Vladimir's comment. I added checks for SubI on both branches of the diamond phi.
Also thanks Roland for the suggestion that supporting a Phi with 3 or more inputs. But I think the matching rule will be much more complex if we add this. And I'm not sure if there are any real case scenario which can benefit from this support. So I didn't add it in.

New webrev: http://cr.openjdk.java.net/~njian/8210152/webrev.01/
I've run jtreg full test with the new patch and no new issues found.

Please let me know if you have other comments or suggestions. If no further issues, I need your help to sponsor and push the patch.

--
Thanks,
Pengfei


> -----Original Message-----
> From: Roland Westrelin <rwestrel at redhat.com>
> Sent: Tuesday, September 11, 2018 16:24
> To: Vladimir Kozlov <vladimir.kozlov at oracle.com>; Pengfei Li (Arm
> Technology China) <Pengfei.Li at arm.com>; dean.long at oracle.com; hotspot-
> compiler-dev at openjdk.java.net; hotspot-dev at openjdk.java.net
> Cc: nd <nd at arm.com>
> Subject: Re: [PING] RE: RFR(S): 8210152: Optimize integer divisible by power-
> of-2 check
> 
> 
> > The only comment I have is to add check for SubI on other branch (not
> > only on True branch). Negation may occur on either branch since you
> > accept all conditions for negation.
> 
> Can't we make this more general and support a phi with any number of
> inputs (not only 2 data inputs) as long as it's a mix of X and -X?
> 
> Roland.