It is the setter that can have a result, but not the StoreInstanceFieldNode.

runtime/vm/opt_code_generator_ia32.cc

 // Copyright (c) 2011, 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_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/opt_code_generator.h"
 
 #include "vm/assembler_macros.h"
@@ skipping 547 matching lines @@
     const Class* cls = NULL;
     classes_for_locals_->GetLocalClass(node->local(), &cls);
     if (cls != NULL) {
       node->info()->set_is_class(cls);
     }
   }
 }
 
 
 void OptimizingCodeGenerator::HandleResult(AstNode* node, Register result_reg) {
-  if (CodeGenerator::IsResultNeeded(node)) {
+  if (IsResultNeeded(node)) {
     if (IsResultInEaxRequested(node)) {
       if (result_reg != EAX) {
         __ movl(EAX, result_reg);
       }
       node->info()->set_result_returned_in_eax(true);
     } else {
       __ pushl(result_reg);
     }
   }
 }
@@ skipping 287 matching lines @@
     __ movl(kResultRegister, kOperandRegister);
   } else {
     const Double& double_object =
         Double::ZoneHandle(Double::New(0.0, Heap::kOld));
     __ LoadObject(kResultRegister, double_object);
   }
   __ movsd(XMM0, FieldAddress(kOperandRegister, Double::value_offset()));
   ASSERT(node->kind() == Token::kSUB);
   __ DoubleNegate(XMM0);
   __ movsd(FieldAddress(kResultRegister, Double::value_offset()), XMM0);
-  if (CodeGenerator::IsResultNeeded(node)) {
+  if (IsResultNeeded(node)) {
     if (node->info() != NULL) {
       node->info()->set_is_temp(using_temp);
       node->info()->set_is_class(&double_class_);
     }
     HandleResult(node, kResultRegister);
   }
 }
 
 
 // Handles only Smi & Smi.
@@ skipping 352 matching lines @@
     }
 
     switch (kind) {
       case Token::kADD: __ addsd(XMM0, XMM1); break;
       case Token::kSUB: __ subsd(XMM0, XMM1); break;
       case Token::kMUL: __ mulsd(XMM0, XMM1); break;
       case Token::kDIV: __ divsd(XMM0, XMM1); break;
       default: UNREACHABLE();
     }
     __ movsd(FieldAddress(result_register, Double::value_offset()), XMM0);
-    if (CodeGenerator::IsResultNeeded(node)) {
+    if (IsResultNeeded(node)) {
       if (node->info() != NULL) {
         node->info()->set_is_temp(using_temp);
         node->info()->set_is_class(&double_class_);
       }
       HandleResult(node, result_register);
     }
     return;
   }
 
   TraceNotOpt(node, kOptMessage);
@@ skipping 739 matching lines @@
 // Right operand can be Smi or null, otherwise call operator on Smi (e.g,
 // when compared with double).
 // This code will be more optimized once we collect types for two arguments.
 void OptimizingCodeGenerator::GenerateSmiEquality(ComparisonNode* node) {
   const Bool& bool_true = Bool::ZoneHandle(Bool::True());
   const Bool& bool_false = Bool::ZoneHandle(Bool::False());
   ASSERT((node->kind() == Token::kEQ) || (node->kind() == Token::kNE));
   CodeGenInfo left_info(node->left());
   CodeGenInfo right_info(node->right());
   VisitLoadTwo(node->left(), node->right(), EAX, EDX);
-  if (!CodeGenerator::IsResultNeeded(node)) {
+  if (!IsResultNeeded(node)) {
     return;
   }
   const Immediate raw_null =
       Immediate(reinterpret_cast<intptr_t>(Object::null()));
   Label evaluate_comparison;
   if (!left_info.IsClass(smi_class_)) {
     DeoptimizationBlob* deopt_blob =
         AddDeoptimizationBlob(node, EAX, EDX, kDeoptSmiEquality);
     Label left_not_null;
     __ cmpl(EAX, raw_null);
@@ skipping 72 matching lines @@
   }
   Condition condition;
   if (!SupportedTokenKindToSmiCondition(node->kind(), &condition)) {
     return false;
   }
   const Bool& bool_true = Bool::ZoneHandle(Bool::True());
   const Bool& bool_false = Bool::ZoneHandle(Bool::False());
   CodeGenInfo left_info(node->left());
   CodeGenInfo right_info(node->right());
   VisitLoadTwo(node->left(), node->right(), EAX, EDX);
-  if (!CodeGenerator::IsResultNeeded(node)) {
+  if (!IsResultNeeded(node)) {
     return true;
   }
   if (left_info.IsClass(smi_class_) && right_info.IsClass(smi_class_)) {
     __ cmpl(EAX, EDX);
   } else if (left_info.IsClass(smi_class_) || right_info.IsClass(smi_class_)) {
     // One is Smi.
     DeoptimizationBlob* deopt_blob =
         AddDeoptimizationBlob(node, EAX, EDX, kDeoptSmiCompareSmis);
     Register reg_to_test = left_info.IsClass(smi_class_) ? EDX : EAX;
     __ testl(reg_to_test, Immediate(kSmiTagMask));
@@ skipping 85 matching lines @@
     if (cls.raw() == smi_class_.raw()) {
       // TODO(srdjan): implement mixed smi/non-smi comparison, for the moment
       // bail out.
       TraceNotOpt(node, "Equality comparison, mixed with Smi");
       return false;
     }
   }
 
   // All targets are Object.==, i.e., '==='. Smi is not among the classes.
   VisitLoadTwo(node->left(), node->right(), EAX, EDX);
-  if (!CodeGenerator::IsResultNeeded(node)) {
+  if (!IsResultNeeded(node)) {
     return true;
   }
   Label compare;
   // Comparison with NULL is "===".
   const Immediate raw_null =
       Immediate(reinterpret_cast<intptr_t>(Object::null()));
   __ cmpl(EAX, raw_null);
   if (num_classes == 0) {
     DeoptimizationBlob* deopt_blob =
         AddDeoptimizationBlob(node, EAX, EDX, kDeoptEqualityNoFeedback);
@@ skipping 73 matching lines @@
   __ comisd(XMM0, XMM1);
   if (NodeInfoHasLabels(node)) {
     __ j(PARITY_EVEN, node->info()->false_label());  // NaN -> false;
     GenerateConditionalJumps(*(node->info()), true_condition);
     node->info()->set_labels_used(true);
   } else {
     Label is_false, is_true, done;
     __ j(PARITY_EVEN, &is_false, Assembler::kNearJump);  // NaN -> false;
     __ j(true_condition, &is_true, Assembler::kNearJump);
     __ Bind(&is_false);
-    if (CodeGenerator::IsResultNeeded(node)) {
+    if (IsResultNeeded(node)) {
       __ PushObject(bool_false);
     }
     __ jmp(&done);
     __ Bind(&is_true);
-    if (CodeGenerator::IsResultNeeded(node)) {
+    if (IsResultNeeded(node)) {
       __ PushObject(bool_true);
     }
     __ Bind(&done);
   }
   return true;
 }
 
 
 // IS, ISNOT are handled in class CodeGenerator.
 void OptimizingCodeGenerator::VisitComparisonNode(ComparisonNode* node) {
   if ((node->kind() == Token::kEQ_STRICT) ||
       (node->kind() == Token::kNE_STRICT)) {
     const Bool& bool_true = Bool::ZoneHandle(Bool::True());
     const Bool& bool_false = Bool::ZoneHandle(Bool::False());
     // Note that evaluation of right may cause deoptimization, therefore left
     // must be on stack when evaluating right.
     if (node->right()->IsLiteralNode()) {
       VisitLoadOne(node->left(), EAX);
       __ CompareObject(EAX, node->right()->AsLiteralNode()->literal());
     } else {
       VisitLoadTwo(node->left(), node->right(), EAX, EDX);
       __ cmpl(EAX, EDX);
     }
-    if (!CodeGenerator::IsResultNeeded(node)) {
+    if (!IsResultNeeded(node)) {
       return;
     }
     Condition condition = node->kind() == Token::kEQ_STRICT ? EQUAL : NOT_EQUAL;
     if (NodeInfoHasLabels(node)) {
       GenerateConditionalJumps(*(node->info()), condition);
       node->info()->set_labels_used(true);
     } else {
       Label done, is_true;
       __ j(condition, &is_true);
       __ PushObject(bool_false);
@@ skipping 748 matching lines @@
 
 
 void OptimizingCodeGenerator::VisitStoreInstanceFieldNode(
     StoreInstanceFieldNode* node) {
   if (FLAG_enable_type_checks) {
     CodeGenerator::VisitStoreInstanceFieldNode(node);
     return;
   }
   VisitLoadTwo(node->instance(), node->value(), EDX, EAX);
   __ StoreIntoObject(EDX, FieldAddress(EDX, node->field().Offset()), EAX);
-  // The result is the input value.
-  HandleResult(node, EAX);
+  ASSERT(!IsResultNeeded(node));
 }
 
 
 void OptimizingCodeGenerator::VisitCatchClauseNode(CatchClauseNode* node) {
   // TODO(srdjan): Set classes for locals.
   classes_for_locals_->Clear();
   CodeGenerator::VisitCatchClauseNode(node);
 }
 
 
@@ skipping 41 matching lines @@
     }
   }
   // TODO(srdjan): Implement unary kSUB (negate) Mint.
   CodeGenerator::VisitUnaryOpNode(node);
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32