Use type propagation to eliminate store barriers.

runtime/vm/intermediate_language_x64.cc

 // Copyright (c) 2012, 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_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
@@ skipping 902 matching lines @@
   __ testq(index, Immediate(kSmiTagMask));
   __ j(NOT_ZERO, deopt);
 
   switch (receiver_type()) {
     case kArrayCid:
     case kImmutableArrayCid:
       __ cmpq(index, FieldAddress(receiver, Array::length_offset()));
       __ j(ABOVE_EQUAL, deopt);
       // Note that index is Smi, i.e, times 4.
       ASSERT(kSmiTagShift == 1);
-      if (this->value()->BindsToConstant()) {
-        // Compile time constants are Smi or allocated in the old space.
-        __ movq(FieldAddress(receiver, index, TIMES_4, sizeof(RawArray)),
-            value);
-      } else {
+      if (this->value()->NeedsStoreBuffer()) {
         __ StoreIntoObject(receiver,
             FieldAddress(receiver, index, TIMES_4, sizeof(RawArray)),
             value);
+      } else {
+        __ StoreIntoObjectNoBarrier(receiver,
+            FieldAddress(receiver, index, TIMES_4, sizeof(RawArray)),
+            value);
       }
       break;
 
     case kGrowableObjectArrayCid: {
       Register temp = locs()->temp(0).reg();
       __ cmpq(index,
               FieldAddress(receiver, GrowableObjectArray::length_offset()));
       __ j(ABOVE_EQUAL, deopt);
       __ movq(temp, FieldAddress(receiver, GrowableObjectArray::data_offset()));
       // Note that index is Smi, i.e, times 4.
       ASSERT(kSmiTagShift == 1);
-      if (this->value()->BindsToConstant()) {
-        // Compile time constants are Smi or allocated in the old space.
-        __ movq(FieldAddress(temp, index, TIMES_4, sizeof(RawArray)),
-            value);
-      } else {
+      if (this->value()->NeedsStoreBuffer()) {
         __ StoreIntoObject(temp,
             FieldAddress(temp, index, TIMES_4, sizeof(RawArray)),
             value);
+      } else {
+        __ StoreIntoObjectNoBarrier(temp,
+            FieldAddress(temp, index, TIMES_4, sizeof(RawArray)),
+            value);
       }
       break;
     }
 
     default:
       UNREACHABLE();
       break;
   }
 }
 
@@ skipping 51 matching lines @@
     Label* deopt = compiler->AddDeoptStub(original()->deopt_id(),
                                           original()->try_index(),
                                           kDeoptInstanceGetterSameTarget);
     // Smis do not have instance fields (Smi class is always first).
     Register temp_reg = locs()->temp(0).reg();
     ASSERT(temp_reg != instance_reg);
     ASSERT(temp_reg != value_reg);
     ASSERT(ic_data() != NULL);
     compiler->EmitClassChecksNoSmi(*ic_data(), instance_reg, temp_reg, deopt);
   }
-  if (this->value()->BindsToConstant()) {
-    // Compile time constants are Smi or allocated in the old space.
-    __ movq(FieldAddress(instance_reg, field().Offset()), value_reg);
+  if (this->value()->NeedsStoreBuffer()) {
+    __ StoreIntoObject(instance_reg,
+        FieldAddress(instance_reg, field().Offset()), value_reg);
   } else {
-    __ StoreIntoObject(instance_reg,
+    __ StoreIntoObjectNoBarrier(instance_reg,
         FieldAddress(instance_reg, field().Offset()), value_reg);
   }
 }
 
 
 LocationSummary* LoadStaticFieldComp::MakeLocationSummary() const {
   return LocationSummary::Make(0,
                                Location::RequiresRegister(),
                                LocationSummary::kNoCall);
 }
@@ skipping 14 matching lines @@
   return locs;
 }
 
 
 void StoreStaticFieldComp::EmitNativeCode(FlowGraphCompiler* compiler) {
   Register value = locs()->in(0).reg();
   Register temp = locs()->temp(0).reg();
   ASSERT(locs()->out().reg() == value);
 
   __ LoadObject(temp, field());
-  if (this->value()->BindsToConstant()) {
-    // Compile time constants are Smi or allocated in the old space.
-    __ movq(FieldAddress(temp, Field::value_offset()), value);
+  if (this->value()->NeedsStoreBuffer()) {
+    __ StoreIntoObject(temp, FieldAddress(temp, Field::value_offset()), value);
   } else {
-    __ StoreIntoObject(temp, FieldAddress(temp, Field::value_offset()), value);
+    __ StoreIntoObjectNoBarrier(
+        temp, FieldAddress(temp, Field::value_offset()), value);
   }
 }
 
 
 LocationSummary* InstanceOfComp::MakeLocationSummary() const {
   const intptr_t kNumInputs = 3;
   const intptr_t kNumTemps = 0;
   LocationSummary* summary =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kCall);
   summary->set_in(0, Location::RegisterLocation(RAX));
@@ skipping 1367 matching lines @@
   __ testq(value, Immediate(kSmiTagMask));
   __ j(NOT_ZERO, deopt);
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64