8152910: Get performance improvement with Stable annotation

[Remi Forax]

Hi Brian,
can you move the [] to the right place at the same time, to use the java syntax not the C one.
i.e.
   @Stable
   private static final BigInteger[] posConst = new BigInteger[MAX_CONSTANT+1];
instead of
   @Stable
   private static final BigInteger posConst[] = new BigInteger[MAX_CONSTANT+1];

cheers,
Rémi

----- Mail original -----
> De: "Brian Burkhalter" <brian.burkhalter at oracle.com>
> À: "core-libs-dev" <core-libs-dev at openjdk.java.net>
> Envoyé: Lundi 1 Octobre 2018 23:31:22
> Objet: 8152910: Get performance improvement with Stable annotation

> Please review at your convenience:
> 
> https://bugs.openjdk.java.net/browse/JDK-8152910
> 
> JMH benchmarks do show a slight but measurable performance improvement with the
> below patch applied.
> 
> Thanks,
> 
> Brian
> 
> --- a/src/java.base/share/classes/java/math/BigInteger.java
> +++ b/src/java.base/share/classes/java/math/BigInteger.java
> @@ -41,6 +41,7 @@
> import jdk.internal.math.DoubleConsts;
> import jdk.internal.math.FloatConsts;
> import jdk.internal.HotSpotIntrinsicCandidate;
> +import jdk.internal.vm.annotation.Stable;
> 
> /**
>  * Immutable arbitrary-precision integers.  All operations behave as if
> @@ -1219,8 +1220,10 @@
>      * Initialize static constant array when class is loaded.
>      */
>     private static final int MAX_CONSTANT = 16;
> -    private static BigInteger posConst[] = new BigInteger[MAX_CONSTANT+1];
> -    private static BigInteger negConst[] = new BigInteger[MAX_CONSTANT+1];
> +    @Stable
> +    private static final BigInteger posConst[] = new
> BigInteger[MAX_CONSTANT+1];
> +    @Stable
> +    private static final BigInteger negConst[] = new
> BigInteger[MAX_CONSTANT+1];