- Issue is reproducible with the following conditions:
    o -XX:+SafepointALot
    o non-product builds.
    o Test point: test/hotspot/jtreg/compiler/c2/cr6340864/TestIntVect.java

CPROMPT>sde64 -future -ptr_raise -- java -XX:TieredStopAtLevel=4 -XX:+SafepointALot -XX:+UnlockExperimentalVMOptions -cp . compiler.c2.cr6340864.TestIntVect
Testing Long vectors
Warmup
#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/home/jatinbha/sandboxes/apx/src/hotspot/cpu/x86/macroAssembler_x86.cpp:832), pid=1832904, tid=1832920
# fatal error: DEBUG MESSAGE: Attempting to adjust pc to skip safepoint poll but the return point is not what we expected

The problem occurs due to missing handling of REX2 prefixed safepoint polling instruction.