[aarch64-port-dev ] Backports from jdk9 to aarch64-port/jdk8u

[Stuart Monteith]

Hi,
   I've been working on some aarch64 patches that should be backported
from jdk9 to aarch64-prot/jdk8u. I've backported the following stack
of patches, and I'm currently testing with them.

Do these look sensible? Are there other I should consider, that are
not specifically AArch64? I've put in 8175887 as it obviously affects
JCStress. I've excluded patches that  are obviously not applicable to
JDK8u - Graal, for example.


8175887: C1 value numbering handling of Unsafe.get*Volatile is incorrect
        https://bugs.openjdk.java.net/browse/JDK-8175887
        http://hg.openjdk.java.net/jdk9/dev/hotspot/rev/2ff05d967fb2

        This isn't strictly an aarch64 issue, but is causing JCStress to fail.

8173472: AArch64: C1 comparisons with null only use 32-bit instructions
        https://bugs.openjdk.java.net/browse/JDK-8173472
        http://hg.openjdk.java.net/jdk9/dev/hotspot/rev/b53b0251e250

        This is a fix for a serious bug that was causing spurious failures.

8172881: AArch64: assertion failure: the int pressure is incorrect
         https://bugs.openjdk.java.net/browse/JDK-8172881
         http://hg.openjdk.java.net/jdk9/dev/hotspot/rev/bfa8e4b0d4e2

        Was causing a SIGSEGV.

8171537: aarch64: compiler/c1/Test6849574.java generates guarantee failure in C1
        https://bugs.openjdk.java.net/browse/JDK-8171537
        http://hg.openjdk.java.net/jdk9/dev/hotspot/rev/a3bd5804b4be


8171410: aarch64: long multiplyExact shifts by 31 instead of 63
        https://bugs.openjdk.java.net/browse/JDK-8171410
        http://hg.openjdk.java.net/jdk9/dev/hotspot/rev/da52f1047024

        Fixes a bug that was causing a slow path to be executed by
mistake. Effectively a performance improvement.

8171129: [aarch64] hs_err logs do not print register mappings
        https://bugs.openjdk.java.net/browse/JDK-8171129
        http://hg.openjdk.java.net/jdk9/dev/hotspot/rev/f3a31c992164

        This is a nice-to-have and could be excluded.

8169177: AArch64: SIGSEGV when "-XX:+ZeroTLAB" is specified along with
GC options
        https://bugs.openjdk.java.net/browse/JDK-8169177
        http://hg.openjdk.java.net/jdk9/dev/hotspot/rev/9831cd4dd428

8170100: AArch64: Crash in C1-compiled code accessing References
        https://bugs.openjdk.java.net/browse/JDK-8170100
        http://hg.openjdk.java.net/jdk9/dev/hotspot/rev/52d18f20804b

8169901: AArch64: CompareAndExchange intrinsics clobber address register
        https://bugs.openjdk.java.net/browse/JDK-8169901
        http://hg.openjdk.java.net/jdk9/dev/hotspot/rev/f5689e544d44

8169497: Aarch64: Improve internal array handling
        https://bugs.openjdk.java.net/browse/JDK-8169497
        http://hg.openjdk.java.net/jdk9/dev/hotspot/rev/824a8dcba48b



I'm currently testing the stack of patches. Shall I post an email with
the patch series? It is 800 lines in length. There was a little fixup
required for some of the
patches.

BR,
    Stuart