MIPS: Fix compile error for unitialized variable in simulator.

src/mips64/simulator-mips64.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <limits.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <cmath>
 
 #include "src/v8.h"
@@ skipping 2976 matching lines @@
 }
 
 
 void Simulator::DecodeTypeRegisterDRsType(Instruction* instr,
                                           const int32_t& fs_reg,
                                           const int32_t& ft_reg,
                                           const int32_t& fd_reg) {
   double ft, fs, fd;
   uint32_t cc, fcsr_cc;
   fs = get_fpu_register_double(fs_reg);
-  if (instr->FunctionFieldRaw() != MOVF) {
-    ft = get_fpu_register_double(ft_reg);
-  }
+  ft = (instr->FunctionFieldRaw() != MOVF) ? get_fpu_register_double(ft_reg)
+                                           : 0.0;
   fd = get_fpu_register_double(fd_reg);
   cc = instr->FCccValue();
   fcsr_cc = get_fcsr_condition_bit(cc);
   int64_t ft_int = bit_cast<int64_t>(ft);
   int64_t fd_int = bit_cast<int64_t>(fd);
   switch (instr->FunctionFieldRaw()) {
     case RINT: {
       DCHECK(kArchVariant == kMips64r6);
       double result, temp, temp_result;
       double upper = std::ceil(fs);
@@ skipping 1569 matching lines @@
   return address;
 }
 
 
 #undef UNSUPPORTED
 } }  // namespace v8::internal
 
 #endif  // USE_SIMULATOR
 
 #endif  // V8_TARGET_ARCH_MIPS64