Use ATTRIBUTE_UNUSED more.

Use it in lieu of UNUSED(), which had some incorrect uses.

Change-Id: If247dce58b72056f6eea84968e7196f0b5bef4da
diff --git a/compiler/dex/quick/x86/utility_x86.cc b/compiler/dex/quick/x86/utility_x86.cc
index b16ae98..61354df 100644
--- a/compiler/dex/quick/x86/utility_x86.cc
+++ b/compiler/dex/quick/x86/utility_x86.cc
@@ -57,8 +57,7 @@
   return res;
 }
 
-bool X86Mir2Lir::InexpensiveConstantInt(int32_t value) {
-  UNUSED(value);
+bool X86Mir2Lir::InexpensiveConstantInt(int32_t value ATTRIBUTE_UNUSED) {
   return true;
 }
 
@@ -66,8 +65,7 @@
   return value == 0;
 }
 
-bool X86Mir2Lir::InexpensiveConstantLong(int64_t value) {
-  UNUSED(value);
+bool X86Mir2Lir::InexpensiveConstantLong(int64_t value ATTRIBUTE_UNUSED) {
   return true;
 }
 
@@ -942,9 +940,14 @@
   return store;
 }
 
-LIR* X86Mir2Lir::OpCmpMemImmBranch(ConditionCode cond, RegStorage temp_reg, RegStorage base_reg,
-                                   int offset, int check_value, LIR* target, LIR** compare) {
-  UNUSED(temp_reg);  // Comparison performed directly with memory.
+LIR* X86Mir2Lir::OpCmpMemImmBranch(ConditionCode cond,
+                                   // Comparison performed directly with memory.
+                                   RegStorage temp_reg ATTRIBUTE_UNUSED,
+                                   RegStorage base_reg,
+                                   int offset,
+                                   int check_value,
+                                   LIR* target,
+                                   LIR** compare) {
   LIR* inst = NewLIR3(IS_SIMM8(check_value) ? kX86Cmp32MI8 : kX86Cmp32MI, base_reg.GetReg(),
       offset, check_value);
   if (compare != nullptr) {
@@ -1114,8 +1117,11 @@
   return loc;
 }
 
-LIR* X86Mir2Lir::InvokeTrampoline(OpKind op, RegStorage r_tgt, QuickEntrypointEnum trampoline) {
-  UNUSED(r_tgt);  // Call to absolute memory location doesn't need a temporary target register.
+LIR* X86Mir2Lir::InvokeTrampoline(OpKind op,
+                                  // Call to absolute memory location doesn't
+                                  // need a temporary target register.
+                                  RegStorage r_tgt ATTRIBUTE_UNUSED,
+                                  QuickEntrypointEnum trampoline) {
   if (cu_->target64) {
     return OpThreadMem(op, GetThreadOffset<8>(trampoline));
   } else {