Merge ConstantInstr -> UnboxDouble to UnboxedConstant. Reduces register usage and allows for variou…

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 21 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.
+    if (*reinterpret_cast<int64_t*>(&value) ==
+        *reinterpret_cast<const int64_t*>(&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 {
  public:
   FlowGraphBuilder* owner() const { return owner_; }
   const SourceLabel* label() const { return label_; }
   NestedStatement* outer() const { return outer_; }
   JoinEntryInstr* break_target() const { return break_target_; }
 
   virtual intptr_t ContextLevel() const;
@@ skipping 3847 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