RFR (S) 8150102: C1 should fold arraylength for constant/trusted arrays
Vladimir Ivanov
vladimir.x.ivanov at oracle.com
Thu Feb 18 08:08:39 UTC 2016
Looks good.
On 2/18/16 2:05 AM, Aleksey Shipilev wrote:
> Hi,
>
> Please review a small tuneup in C1 arraylength folding:
> https://bugs.openjdk.java.net/browse/JDK-8150102
> http://cr.openjdk.java.net/~shade/8150102/webrev.00
>
> After this patch, C1 successfully folds the general arraylength
> accesses. In the end, this lets to fold String.length() for constant
> Strings:
> http://cr.openjdk.java.net/~shade/8150102/FoldArrayLength.java
>
> I am actually wondering if as_LoadField path is ever hit in
> applications, because the targeted microbenchmark for static final array
> had improved with new as_Constant path.
I don't think it happens. GraphBuilder::access_field already folds loads
into constants.
Best regards,
Vladimir Ivanov
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