hg: jdk9/hs-comp/hotspot: 8080293: AARCH64: Remove unnecessary dmbs from generated CAS code

[edward.nevill at gmail.com]

Changeset: 95e96bd4b70b
Author:    adinn
Date:      2015-09-16 09:52 -0400
URL:       http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/95e96bd4b70b

8080293: AARCH64: Remove unnecessary dmbs from generated CAS code
Summary: The current encoding for CAS generates unnecessary leading and trailing dmbs for the MemBarAcquire and MemBarRelease which ought to be elided
Reviewed-by: kvn

! src/cpu/aarch64/vm/aarch64.ad