[CPU] Remove ATOMIC_EXCHANGE opcode (dead code)

src/xenia/cpu/hir/hir_builder.cc

@@ -2225,17 +2225,6 @@ Value* HIRBuilder::Unpack(Value* value, uint32_t pack_flags) {
   return i->dest;
 }
 
-Value* HIRBuilder::AtomicExchange(Value* address, Value* new_value) {
-  ASSERT_ADDRESS_TYPE(address);
-  ASSERT_INTEGER_TYPE(new_value);
-  Instr* i =
-      AppendInstr(OPCODE_ATOMIC_EXCHANGE_info, 0, AllocValue(new_value->type));
-  i->set_src1(address);
-  i->set_src2(new_value);
-  i->src3.value = NULL;
-  return i->dest;
-}
-
 Value* HIRBuilder::AtomicCompareExchange(Value* address, Value* old_value,
                                          Value* new_value) {
   ASSERT_ADDRESS_TYPE(address);

src/xenia/cpu/hir/hir_builder.h

@@ -297,7 +297,6 @@ class HIRBuilder {
   Value* Pack(Value* value1, Value* value2, uint32_t pack_flags = 0);
   Value* Unpack(Value* value, uint32_t pack_flags = 0);
 
-  Value* AtomicExchange(Value* address, Value* new_value);
   Value* AtomicCompareExchange(Value* address, Value* old_value,
                                Value* new_value);
   Value* AtomicAdd(Value* address, Value* value);

src/xenia/cpu/hir/opcodes.h

@@ -282,7 +282,6 @@ enum Opcode {
   OPCODE_PACK,  // break up into smaller operations and add a float16 convert
                 // opcode
   OPCODE_UNPACK,
-  OPCODE_ATOMIC_EXCHANGE,
   OPCODE_ATOMIC_COMPARE_EXCHANGE,
   OPCODE_SET_ROUNDING_MODE,
   OPCODE_VECTOR_DENORMFLUSH,  // converts denormals to signed zeros in a vector

src/xenia/cpu/hir/opcodes.inl

@@ -650,12 +650,6 @@ DEFINE_OPCODE(
     OPCODE_SIG_V_V,
     0)
 
-DEFINE_OPCODE(
-    OPCODE_ATOMIC_EXCHANGE,
-    "atomic_exchange",
-    OPCODE_SIG_V_V_V,
-    OPCODE_FLAG_VOLATILE)
-
 DEFINE_OPCODE(
     OPCODE_ATOMIC_COMPARE_EXCHANGE,
     "atomic_compare_exchange",