Further x86 progress and image creation.

Change-Id: Idafadfc55228541536f25d2c92d40d9e0510b602
diff --git a/src/compiler/codegen/x86/X86LIR.h b/src/compiler/codegen/x86/X86LIR.h
index 9b9fc6b..378c24d 100644
--- a/src/compiler/codegen/x86/X86LIR.h
+++ b/src/compiler/codegen/x86/X86LIR.h
@@ -436,6 +436,7 @@
     Binary0fOpCode(kX86Movdxr),     // move into xmm from gpr
     Binary0fOpCode(kX86Movdrx),     // move into reg from xmm
     kX86Set8R, kX86Set8M, kX86Set8A,// set byte depending on condition operand
+    kX86Mfence,                     // memory barrier
     Binary0fOpCode(kX86Imul16),     // 16bit multiply
     Binary0fOpCode(kX86Imul32),     // 32bit multiply
     Binary0fOpCode(kX86Movzx8),     // zero-extend 8-bit value