Fuse Comparison->BooleanNegate->Branch.

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 524 matching lines @@
                                         left,
                                         right);
   compiler->LoadDoubleOrSmiToXmm(XMM0, left, temp, deopt);
   compiler->LoadDoubleOrSmiToXmm(XMM1, right, temp, deopt);
 
   Condition true_condition = TokenKindToDoubleCondition(comp->kind());
   __ comisd(XMM0, XMM1);
 
   if (comp->is_fused_with_branch()) {
     BranchInstr* branch = comp->fused_with_branch();
-    __ j(PARITY_EVEN, compiler->GetBlockLabel(branch->false_successor()));
+    BlockEntryInstr* nan_result = branch->is_negated() ?
+        branch->true_successor() : branch->false_successor();
+    __ j(PARITY_EVEN, compiler->GetBlockLabel(nan_result));
     branch->EmitBranchOnCondition(compiler, true_condition);
   } else {
     Register result = comp->locs()->out().reg();
     Label is_false, is_true, done;
     __ j(PARITY_EVEN, &is_false, Assembler::kNearJump);
     __ j(true_condition, &is_true, Assembler::kNearJump);
     __ Bind(&is_false);
     __ LoadObject(result, compiler->bool_false());
     __ jmp(&done);
     __ Bind(&is_true);
@@ skipping 1259 matching lines @@
                                  instance_call()->argument_names());
   }
   __ Bind(&done);
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64