hg: jdk9/hs/hotspot: 8167987: change merge context to clear for mask register usage model

[vladimir.kozlov at oracle.com]

Changeset: d5c67c13e5f9
Author:    mcberg
Date:      2016-10-18 19:08 -0700
URL:       http://hg.openjdk.java.net/jdk9/hs/hotspot/rev/d5c67c13e5f9

8167987: change merge context to clear for mask register usage model
Reviewed-by: kvn

! src/cpu/x86/vm/assembler_x86.cpp
! src/cpu/x86/vm/assembler_x86.hpp