RFR(M): 8220376: C2: Int >0 not recognized as !=0 for div by 0 check

[Doerr, Martin]

Hi Patric,

thanks for addressing this issue.

There seems to be a small issue with the webrev:
-  if (bol->is_Bool()) {
+  if (!bol->is_Bool()) {

I guess you have tested it already this way and just something with the webrev went wrong.

You recognize and transform a specific pattern you have described in the comment. It is appropriate for fixing this example and it looks good to me. But I'm curious how often this matches. Maybe we can see a performance improvement.

Thanks and best regards,
Martin


> -----Original Message-----
> From: hotspot-compiler-dev <hotspot-compiler-dev-
> bounces at openjdk.java.net> On Behalf Of Nils Eliasson
> Sent: Mittwoch, 13. November 2019 17:13
> To: hotspot-compiler-dev at openjdk.java.net
> Subject: Re: RFR(M): 8220376: C2: Int >0 not recognized as !=0 for div by 0
> check
> 
> Hi Patric,
> 
> Looks good!
> 
> (I have pre-reviewed this patch offline)
> 
> Regards,
> 
> Nils
> 
> On 2019-11-12 15:16, Patric Hedlin wrote:
> > Dear all,
> >
> > I would like to ask for help to review the following change/update:
> >
> > Issue:  https://bugs.openjdk.java.net/browse/JDK-8220376
> > Webrev: http://cr.openjdk.java.net/~phedlin/tr8220376/
> >
> > 8220376: C2: Int >0 not recognized as !=0 for div by 0 check
> >
> >     Adding a simple subsumption test to IfNode::Ideal to enable a local
> >     short-circuit for (obviously) redundant if-nodes.
> >
> > Testing: hs-tier1-4, hs-precheckin-comp
> >
> >
> > Best regards,
> > Patric
> >