Added thin-lock fast path for monitor-enter/exit on x86.

Change-Id: Iba187ae1acde6e341ae510d4b47f59e6984fc354
diff --git a/src/compiler/codegen/x86/Assemble.cc b/src/compiler/codegen/x86/Assemble.cc
index a245660..0c5d3cf 100644
--- a/src/compiler/codegen/x86/Assemble.cc
+++ b/src/compiler/codegen/x86/Assemble.cc
@@ -298,6 +298,14 @@
 
   EXT_0F_ENCODING_MAP(Imul16,  0x66, 0xAF, REG_DEF0 | SETS_CCODES),
   EXT_0F_ENCODING_MAP(Imul32,  0x00, 0xAF, REG_DEF0 | SETS_CCODES),
+
+  { kX86CmpxchgRR, kRegRegStore, IS_BINARY_OP | REG_DEF0 | REG_USE01 | REG_DEFA_USEA | SETS_CCODES, { 0, 0, 0x0F, 0xB1, 0, 0, 0, 0 }, "Cmpxchg", "!0r,!1r" },
+  { kX86CmpxchgMR, kMemReg,   IS_STORE | IS_TERTIARY_OP | REG_USE02 | REG_DEFA_USEA | SETS_CCODES, { 0, 0, 0x0F, 0xB1, 0, 0, 0, 0 }, "Cmpxchg", "[!0r+!1d],!2r" },
+  { kX86CmpxchgAR, kArrayReg, IS_STORE | IS_QUIN_OP | REG_USE014 | REG_DEFA_USEA | SETS_CCODES, { 0, 0, 0x0F, 0xB1, 0, 0, 0, 0 }, "Cmpxchg", "[!0r+!1r<<!2d+!3d],!4r" },
+  { kX86LockCmpxchgRR, kRegRegStore, IS_BINARY_OP | REG_DEF0 | REG_USE01 | REG_DEFA_USEA | SETS_CCODES, { 0xF0, 0, 0x0F, 0xB1, 0, 0, 0, 0 }, "Lock Cmpxchg", "!0r,!1r" },
+  { kX86LockCmpxchgMR, kMemReg,   IS_STORE | IS_TERTIARY_OP | REG_USE02 | REG_DEFA_USEA | SETS_CCODES, { 0xF0, 0, 0x0F, 0xB1, 0, 0, 0, 0 }, "Lock Cmpxchg", "[!0r+!1d],!2r" },
+  { kX86LockCmpxchgAR, kArrayReg, IS_STORE | IS_QUIN_OP | REG_USE014 | REG_DEFA_USEA | SETS_CCODES, { 0xF0, 0, 0x0F, 0xB1, 0, 0, 0, 0 }, "Lock Cmpxchg", "[!0r+!1r<<!2d+!3d],!4r" },
+
   EXT_0F_ENCODING_MAP(Movzx8,  0x00, 0xB6, REG_DEF0),
   EXT_0F_ENCODING_MAP(Movzx16, 0x00, 0xB7, REG_DEF0),
   EXT_0F_ENCODING_MAP(Movsx8,  0x00, 0xBE, REG_DEF0),