DBC: UnboxedConstantInstr

runtime/vm/intermediate_language_dbc.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_DBC.
 #if defined(TARGET_ARCH_DBC)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/cpu.h"
@@ skipping 22 matching lines @@
   M(LoadCodeUnits)                                                             \
   M(LoadUntagged)                                                              \
   M(AllocateUninitializedContext)                                              \
   M(BinaryInt32Op)                                                             \
   M(Int32ToDouble)                                                             \
   M(DoubleToInteger)                                                           \
   M(DoubleToSmi)                                                               \
   M(DoubleToDouble)                                                            \
   M(DoubleToFloat)                                                             \
   M(FloatToDouble)                                                             \
-  M(UnboxedConstant)                                                           \
   M(MathUnary)                                                                 \
   M(MathMinMax)                                                                \
   M(BoxInt64)                                                                  \
   M(InvokeMathCFunction)                                                       \
   M(MergedMath)                                                                \
   M(GuardFieldClass)                                                           \
   M(GuardFieldLength)                                                          \
   M(IfThenElse)                                                                \
   M(ExtractNthOutput)                                                          \
   M(BinaryUint32Op)                                                            \
@@ skipping 247 matching lines @@
 
 EMIT_NATIVE_CODE(Constant, 0, Location::RequiresRegister()) {
   if (compiler->is_optimizing()) {
     __ LoadConstant(locs()->out(0).reg(), value());
   } else {
     __ PushConstant(value());
   }
 }
 
 
+EMIT_NATIVE_CODE(UnboxedConstant, 0, Location::RequiresRegister()) {
+  // The register allocator drops constant definitions that have no uses.
+  if (locs()->out(0).IsInvalid()) {
+    return;
+  }
+  if (representation_ != kUnboxedDouble) {
+    Unsupported(compiler);
+    UNREACHABLE();
+  }
+  const Register result = locs()->out(0).reg();
+  if (Utils::DoublesBitEqual(Double::Cast(value()).value(), 0.0)) {
+    __ BitXor(result, result, result);
+  } else {
+    __ LoadConstant(result, value());
+    __ UnboxDouble(result, result);
+  }
+}
+
+
 EMIT_NATIVE_CODE(Return, 1) {
   if (compiler->is_optimizing()) {
     __ Return(locs()->in(0).reg());
   } else {
     __ ReturnTOS();
   }
 }
 
 
 LocationSummary* StoreStaticFieldInstr::MakeLocationSummary(
@@ skipping 1117 matching lines @@
   __ IfULe(length, index);
   compiler->EmitDeopt(deopt_id(),
                       ICData::kDeoptCheckArrayBound,
                       (generalized_ ? ICData::kGeneralized : 0) |
                       (licm_hoisted_ ? ICData::kHoisted : 0));
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_DBC