Enables optimization on MIPS

runtime/vm/constants_mips.h

 // Copyright (c) 2013, 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.
 
 #ifndef VM_CONSTANTS_MIPS_H_
 #define VM_CONSTANTS_MIPS_H_
 
 #include "platform/assert.h"
 
 namespace dart {
@@ skipping 111 matching lines @@
   F26 = 26,
   F27 = 27,
   F28 = 28,
   F29 = 29,
   F30 = 30,
   F31 = 31,
   kNumberOfFRegisters = 32,
   kNoFRegister = -1,
 };
 
+// The double precision floating point registers are concatenated pairs of the
+// single precision registers, e.g. D0 is F1:F0, D1 is F3:F2, etc.. We only
+// tell the architecture generic code about the double precision registers, then
+// convert to the single precision registers when needed in the mips-specific
+// code.
+enum DRegister {
+  D0  =  0,
+  D1  =  1,
+  D2  =  2,
+  D3  =  3,
+  D4  =  4,
+  D5  =  5,
+  D6  =  6,
+  D7  =  7,
+  D8  =  8,
+  D9  =  9,
+  D10 = 10,
+  D11 = 11,
+  D12 = 12,
+  D13 = 13,
+  D14 = 14,
+  D15 = 15,
+  D16 = 16,
+  kNumberOfDRegisters = 16,
+  kNoDRegister = -1,
+};
 
 // Architecture independent aliases.
-typedef FRegister FpuRegister;
-const FpuRegister FpuTMP = F0;
-const int kNumberOfFpuRegisters = kNumberOfFRegisters;
-const FpuRegister kNoFpuRegister = kNoFRegister;
+typedef DRegister FpuRegister;
+const FpuRegister FpuTMP = D0;
+const int kNumberOfFpuRegisters = kNumberOfDRegisters;
+const FpuRegister kNoFpuRegister = kNoDRegister;
 
 
 // Register aliases.
 const Register TMP1 = AT;  // Used as scratch register by assembler.
 const Register TMP = TMP1;  // Arch independent flow graph compiler needs a
                             // Register called TMP.
 const Register CTX = S6;  // Caches current context in generated code.
 const Register PP = S7;  // Caches object pool pointer in generated code.
 const Register SPREG = SP;  // Stack pointer register.
 const Register FPREG = FP;  // Frame pointer register.
@@ skipping 417 matching lines @@
 #endif  // defined(DEBUG)
 
  private:
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Instr);
 };
 
 }  // namespace dart
 
 #endif  // VM_CONSTANTS_MIPS_H_