--- a/hotspot/src/cpu/aarch64/vm/aarch64.ad	Tue Aug 22 08:37:17 2017 -0400
+++ b/hotspot/src/cpu/aarch64/vm/aarch64.ad	Tue Aug 22 17:24:40 2017 +0300
@@ -4415,6 +4415,22 @@
                /*weak*/ false, noreg);
   %}
 
+  enc_class aarch64_enc_cmpxchgs(memory mem, iRegINoSp oldval, iRegINoSp newval) %{
+    MacroAssembler _masm(&cbuf);
+    guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
+    __ cmpxchg($mem$$base$$Register, $oldval$$Register, $newval$$Register,
+               Assembler::halfword, /*acquire*/ false, /*release*/ true,
+               /*weak*/ false, noreg);
+  %}
+
+  enc_class aarch64_enc_cmpxchgb(memory mem, iRegINoSp oldval, iRegINoSp newval) %{
+    MacroAssembler _masm(&cbuf);
+    guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
+    __ cmpxchg($mem$$base$$Register, $oldval$$Register, $newval$$Register,
+               Assembler::byte, /*acquire*/ false, /*release*/ true,
+               /*weak*/ false, noreg);
+  %}  
+    
 
   // The only difference between aarch64_enc_cmpxchg and
   // aarch64_enc_cmpxchg_acq is that we use load-acquire in the
@@ -9637,6 +9653,42 @@
 // XXX No flag versions for CompareAndSwap{I,L,P,N} because matcher
 // can't match them
 
+instruct compareAndSwapB(iRegINoSp res, indirect mem, iRegINoSp oldval, iRegINoSp newval, rFlagsReg cr) %{
+
+  match(Set res (CompareAndSwapB mem (Binary oldval newval)));
+  ins_cost(2 * VOLATILE_REF_COST);
+
+  effect(KILL cr);
+
+  format %{
+    "cmpxchgb $mem, $oldval, $newval\t# (int) if $mem == $oldval then $mem <-- $newval"
+    "cset $res, EQ\t# $res <-- (EQ ? 1 : 0)"
+  %}
+
+  ins_encode(aarch64_enc_cmpxchgb(mem, oldval, newval),
+            aarch64_enc_cset_eq(res));
+
+  ins_pipe(pipe_slow);
+%}
+
+instruct compareAndSwapS(iRegINoSp res, indirect mem, iRegINoSp oldval, iRegINoSp newval, rFlagsReg cr) %{
+
+  match(Set res (CompareAndSwapS mem (Binary oldval newval)));
+  ins_cost(2 * VOLATILE_REF_COST);
+
+  effect(KILL cr);
+
+  format %{
+    "cmpxchgs $mem, $oldval, $newval\t# (int) if $mem == $oldval then $mem <-- $newval"
+    "cset $res, EQ\t# $res <-- (EQ ? 1 : 0)"
+  %}
+
+  ins_encode(aarch64_enc_cmpxchgs(mem, oldval, newval),
+            aarch64_enc_cset_eq(res));
+
+  ins_pipe(pipe_slow);
+%}
+
 instruct compareAndSwapI(iRegINoSp res, indirect mem, iRegINoSp oldval, iRegINoSp newval, rFlagsReg cr) %{
 
   match(Set res (CompareAndSwapI mem (Binary oldval newval)));