Use xorps xmm1, xmm1 to creat a 0.0 cconstant. Add to utils a bitwise double test.

runtime/vm/flow_graph_builder.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/flow_graph_builder.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/class_finalizer.h"
@@ skipping 22 matching lines @@
 
 DEFINE_FLAG(bool, eliminate_type_checks, true,
             "Eliminate type checks when allowed by static type analysis.");
 DEFINE_FLAG(bool, print_ast, false, "Print abstract syntax tree.");
 DEFINE_FLAG(bool, print_scopes, false, "Print scopes of local variables.");
 DEFINE_FLAG(bool, trace_type_check_elimination, false,
             "Trace type check elimination at compile time.");
 DECLARE_FLAG(bool, enable_type_checks);
 
 
-
 // TODO(srdjan): Allow compiler to add constants as they are encountered in
 // the compilation.
 const double kCommonDoubleConstants[] =
     {-1.0, -0.5, -0.1, 0.0, 0.1, 0.5, 1.0, 2.0, 4.0, 5.0,
      10.0, 20.0, 30.0, 64.0, 255.0, NAN,
      // From dart:math
      2.718281828459045, 2.302585092994046, 0.6931471805599453,
      1.4426950408889634, 0.4342944819032518, 3.1415926535897932,
      0.7071067811865476, 1.4142135623730951};
 
 uword FlowGraphBuilder::FindDoubleConstant(double value) {
   intptr_t len = sizeof(kCommonDoubleConstants) / sizeof(double);  // NOLINT
   for (intptr_t i = 0; i < len; i++) {
-    // Bitwise compare.
-    const int64_t* a = reinterpret_cast<const int64_t*>(&value);
-    const int64_t* b =
-        reinterpret_cast<const int64_t*>(&kCommonDoubleConstants[i]);
-    if (*a == *b) {
+    if (Utils::DoublesBitEqual(value, kCommonDoubleConstants[i])) {
       return reinterpret_cast<uword>(&kCommonDoubleConstants[i]);
     }
   }
   return 0;
 }
 
 
 // Base class for a stack of enclosing statements of interest (e.g.,
 // blocks (breakable) and loops (continuable)).
 class NestedStatement : public ValueObject {
@@ skipping 3857 matching lines @@
                                   function.token_pos(),
                                   LanguageError::kError,
                                   Heap::kNew,
                                   "FlowGraphBuilder Bailout: %s %s",
                                   String::Handle(function.name()).ToCString(),
                                   reason));
   Isolate::Current()->long_jump_base()->Jump(1, error);
 }
 
 }  // namespace dart