VM: Improve and fix double negation on MIPS.

runtime/vm/intermediate_language_mips.cc

 // 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.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
@@ skipping 4100 matching lines @@
       break;
     default:
       UNREACHABLE();
   }
 }
 
 
 LocationSummary* UnaryDoubleOpInstr::MakeLocationSummary(Zone* zone,
                                                          bool opt) const {
   const intptr_t kNumInputs = 1;
-  const intptr_t kNumTemps = 1;
+  const intptr_t kNumTemps = 0;
   LocationSummary* summary = new(zone) LocationSummary(
       zone, kNumInputs, kNumTemps, LocationSummary::kNoCall);
   summary->set_in(0, Location::RequiresFpuRegister());
   summary->set_out(0, Location::RequiresFpuRegister());
-  summary->set_temp(0, Location::RequiresFpuRegister());
   return summary;
 }
 
 
 void UnaryDoubleOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  // TODO(zra): Implement vneg.
-  const Double& minus_one = Double::ZoneHandle(Double::NewCanonical(-1));
-  __ LoadObject(TMP, minus_one);
   FpuRegister result = locs()->out(0).fpu_reg();
   FpuRegister value = locs()->in(0).fpu_reg();
-  FpuRegister temp_fp = locs()->temp(0).fpu_reg();
-  __ LoadDFromOffset(temp_fp, TMP, Double::value_offset() - kHeapObjectTag);
-  __ muld(result, value, temp_fp);
+  __ negd(result, value);
 }
 
 
 LocationSummary* Int32ToDoubleInstr::MakeLocationSummary(Zone* zone,
                                                        bool opt) const {
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 0;
   LocationSummary* result = new(zone) LocationSummary(
       zone, kNumInputs, kNumTemps, LocationSummary::kNoCall);
   result->set_in(0, Location::RequiresRegister());
@@ skipping 1453 matching lines @@
                                 1,
                                 locs());
   __ lw(result, Address(SP, 1 * kWordSize));
   __ addiu(SP, SP, Immediate(2 * kWordSize));
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS