Fix a perfrormance degradation in Mandelbrot: double comparison may have

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 2259 matching lines @@
 // Return false if the code cannot be generated.
 bool OptimizingCodeGenerator::GenerateDoubleComparison(ComparisonNode* node) {
   Condition true_condition;
   if (!SupportedTokenKindToDoubleCondition(node->kind(), &true_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());
+  left_info.set_allow_temp(true);
+  right_info.set_allow_temp(true);
   VisitLoadTwo(node->left(), node->right(), EAX, EDX);
   DeoptimizationBlob* deopt_blob = NULL;
   if (!left_info.IsClass(double_class_) || !right_info.IsClass(double_class_)) {
     deopt_blob = AddDeoptimizationBlob(node, EAX, EDX, kDeoptDoubleComparison);
   }
   if (!left_info.IsClass(double_class_)) {
     CheckIfDoubleOrSmi(EAX, EBX, deopt_blob->label(), deopt_blob->label());
     PropagateBackLocalClass(node->left(), double_class_);
   }
   if (!right_info.IsClass(double_class_)) {
@@ skipping 73 matching lines @@
     return;
   }
 
   if (AtIdNodeHasClassAt(node, node->id(), smi_class_, 0)) {
     if (GenerateSmiComparison(node)) {
       // The comparison was handled, code was emitted.
       return;
     }
     // Fall through if condition is not supported.
   } else if (AtIdNodeHasClassAt(node, node->id(), double_class_, 0)) {
-    // Double comparison
+    // Double comparison.
     if (GenerateDoubleComparison(node)) {
       return;
     }
   } else if ((node->kind() == Token::kEQ) || (node->kind() == Token::kNE)) {
     // Equality, not-equality comparison of any other type.
     if (GenerateEqualityComparison(node)) {
       return;
     }
   }
 
@@ skipping 744 matching lines @@
     }
   }
   // TODO(srdjan): Implement unary kSUB (negate) Mint.
   CodeGenerator::VisitUnaryOpNode(node);
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32