--- old/src/hotspot/cpu/x86/x86_64.ad	2018-11-26 21:29:44.336273630 +0100
+++ new/src/hotspot/cpu/x86/x86_64.ad	2018-11-26 21:29:44.183274979 +0100
@@ -530,6 +530,9 @@
 #if INCLUDE_ZGC
 #include "gc/z/zBarrierSetAssembler.hpp"
 #endif
+#if INCLUDE_SHENANDOAHGC
+#include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
+#endif
 %}
 
 //----------SOURCE BLOCK-------------------------------------------------------
@@ -6692,6 +6695,59 @@
   ins_pipe(ialu_reg_reg); // XXX
 %}
 
+instruct shenandoahRB(rRegP dst, rRegP src, rFlagsReg cr) %{
+  match(Set dst (ShenandoahReadBarrier src));
+  effect(DEF dst, USE src);
+  ins_cost(125); // XXX
+  format %{ "shenandoah_rb $dst, $src" %}
+  ins_encode %{
+#if INCLUDE_SHENANDOAHGC
+    Register d = $dst$$Register;
+    Register s = $src$$Register;
+    __ movptr(d, Address(s, ShenandoahBrooksPointer::byte_offset()));
+#else
+    ShouldNotReachHere();
+#endif
+  %}
+  ins_pipe(ialu_reg_mem);
+%}
+
+instruct shenandoahRBNarrow(rRegP dst, rRegN src) %{
+  predicate(UseCompressedOops && (Universe::narrow_oop_shift() == 0));
+  match(Set dst (ShenandoahReadBarrier (DecodeN src)));
+  effect(DEF dst, USE src);
+  ins_cost(125); // XXX
+  format %{ "shenandoah_rb $dst, $src" %}
+  ins_encode %{
+#if INCLUDE_SHENANDOAHGC
+    Register d = $dst$$Register;
+    Register s = $src$$Register;
+    __ movptr(d, Address(r12, s, Address::times_1, ShenandoahBrooksPointer::byte_offset()));
+#else
+    ShouldNotReachHere();
+#endif
+  %}
+  ins_pipe(ialu_reg_mem);
+%}
+
+instruct shenandoahRBNarrowShift(rRegP dst, rRegN src) %{
+  predicate(UseCompressedOops && (Universe::narrow_oop_shift() == Address::times_8));
+  match(Set dst (ShenandoahReadBarrier (DecodeN src)));
+  effect(DEF dst, USE src);
+  ins_cost(125); // XXX
+  format %{ "shenandoah_rb $dst, $src" %}
+  ins_encode %{
+#if INCLUDE_SHENANDOAHGC
+    Register d = $dst$$Register;
+    Register s = $src$$Register;
+    __ movptr(d, Address(r12, s, Address::times_8, ShenandoahBrooksPointer::byte_offset()));
+#else
+    ShouldNotReachHere();
+#endif
+  %}
+  ins_pipe(ialu_reg_mem);
+%}
+
 // Convert oop pointer into compressed form
 instruct encodeHeapOop(rRegN dst, rRegP src, rFlagsReg cr) %{
   predicate(n->bottom_type()->make_ptr()->ptr() != TypePtr::NotNull);
@@ -7561,6 +7617,33 @@
   ins_pipe( pipe_cmpxchg );
 %}
 
+instruct compareAndSwapP_shenandoah(rRegI res,
+                                    memory mem_ptr,
+                                    rRegP tmp1, rRegP tmp2,
+                                    rax_RegP oldval, rRegP newval,
+                                    rFlagsReg cr)
+%{
+  predicate(VM_Version::supports_cx8());
+  match(Set res (ShenandoahCompareAndSwapP mem_ptr (Binary oldval newval)));
+  match(Set res (ShenandoahWeakCompareAndSwapP mem_ptr (Binary oldval newval)));
+  effect(TEMP tmp1, TEMP tmp2, KILL cr, KILL oldval);
+
+  format %{ "shenandoah_cas_oop $mem_ptr,$newval" %}
+
+  ins_encode %{
+#if INCLUDE_SHENANDOAHGC
+    ShenandoahBarrierSet::assembler()->cmpxchg_oop(&_masm,
+                                                   $res$$Register, $mem_ptr$$Address, $oldval$$Register, $newval$$Register,
+                                                   false, // swap
+                                                   false, $tmp1$$Register, $tmp2$$Register
+                                                   );
+#else
+    ShouldNotReachHere();
+#endif
+  %}
+  ins_pipe( pipe_cmpxchg );
+%}
+
 instruct compareAndSwapL(rRegI res,
                          memory mem_ptr,
                          rax_RegL oldval, rRegL newval,
@@ -7682,6 +7765,31 @@
   ins_pipe( pipe_cmpxchg );
 %}
 
+instruct compareAndSwapN_shenandoah(rRegI res,
+                                    memory mem_ptr,
+                                    rRegP tmp1, rRegP tmp2,
+                                    rax_RegN oldval, rRegN newval,
+                                    rFlagsReg cr) %{
+  match(Set res (ShenandoahCompareAndSwapN mem_ptr (Binary oldval newval)));
+  match(Set res (ShenandoahWeakCompareAndSwapN mem_ptr (Binary oldval newval)));
+  effect(TEMP tmp1, TEMP tmp2, KILL cr, KILL oldval);
+
+  format %{ "shenandoah_cas_oop $mem_ptr,$newval" %}
+
+  ins_encode %{
+#if INCLUDE_SHENANDOAHGC
+    ShenandoahBarrierSet::assembler()->cmpxchg_oop(&_masm,
+                                                   $res$$Register, $mem_ptr$$Address, $oldval$$Register, $newval$$Register,
+                                                   false, // swap
+                                                   false, $tmp1$$Register, $tmp2$$Register
+                                                   );
+#else
+    ShouldNotReachHere();
+#endif
+  %}
+  ins_pipe( pipe_cmpxchg );
+%}
+
 instruct compareAndExchangeB(
                          memory mem_ptr,
                          rax_RegI oldval, rRegI newval,
@@ -7778,6 +7886,29 @@
   ins_pipe( pipe_cmpxchg );
 %}
 
+instruct compareAndExchangeN_shenandoah(memory mem_ptr,
+                                        rax_RegN oldval, rRegN newval,
+                                        rRegP tmp1, rRegP tmp2,
+                                        rFlagsReg cr) %{
+  match(Set oldval (ShenandoahCompareAndExchangeN mem_ptr (Binary oldval newval)));
+  effect(TEMP tmp1, TEMP tmp2, KILL cr);
+
+  format %{ "shenandoah_cas_oop $mem_ptr,$newval" %}
+
+  ins_encode %{
+#if INCLUDE_SHENANDOAHGC
+    ShenandoahBarrierSet::assembler()->cmpxchg_oop(&_masm,
+                                                   NULL, $mem_ptr$$Address, $oldval$$Register, $newval$$Register,
+                                                   true, // exchange
+                                                   false, $tmp1$$Register, $tmp2$$Register
+                                                   );
+#else
+    ShouldNotReachHere();
+#endif
+  %}
+  ins_pipe( pipe_cmpxchg );
+%}
+
 instruct compareAndExchangeP(
                          memory mem_ptr,
                          rax_RegP oldval, rRegP newval,
@@ -7798,6 +7929,32 @@
   ins_pipe( pipe_cmpxchg );
 %}
 
+instruct compareAndExchangeP_shenandoah(memory mem_ptr,
+                                        rax_RegP oldval, rRegP newval,
+                                        rRegP tmp1, rRegP tmp2,
+                                        rFlagsReg cr)
+%{
+  predicate(VM_Version::supports_cx8());
+  match(Set oldval (ShenandoahCompareAndExchangeP mem_ptr (Binary oldval newval)));
+  effect(KILL cr, TEMP tmp1, TEMP tmp2);
+  ins_cost(1000);
+
+  format %{ "shenandoah_cas_oop $mem_ptr,$newval" %}
+
+  ins_encode %{
+#if INCLUDE_SHENANDOAHGC
+    ShenandoahBarrierSet::assembler()->cmpxchg_oop(&_masm,
+                                                   NULL, $mem_ptr$$Address, $oldval$$Register, $newval$$Register,
+                                                   true,  // exchange
+                                                   false, $tmp1$$Register, $tmp2$$Register
+                                                   );
+#else
+    ShouldNotReachHere();
+#endif
+  %}
+  ins_pipe( pipe_cmpxchg );
+%}
+
 instruct xaddB_no_res( memory mem, Universe dummy, immI add, rFlagsReg cr) %{
   predicate(n->as_LoadStore()->result_not_used());
   match(Set dummy (GetAndAddB mem add));