[turbofan] Add support for reinterpreting integers as floating point and vice versa.

src/compiler/mips64/code-generator-mips64.cc

 // Copyright 2014 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 "src/compiler/code-generator.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/osr.h"
 #include "src/mips/macro-assembler-mips.h"
@@ skipping 781 matching lines @@
       __ trunc_w_d(scratch, i.InputDoubleRegister(0));
       __ mfc1(i.OutputRegister(), scratch);
       break;
     }
     case kMips64TruncUwD: {
       FPURegister scratch = kScratchDoubleReg;
       // TODO(plind): Fix wrong param order of Trunc_uw_d() macro-asm function.
       __ Trunc_uw_d(i.InputDoubleRegister(0), i.OutputRegister(), scratch);
       break;
     }
+    case kMips64BitcastDL:
+      __ dmfc1(i.OutputRegister(), i.InputDoubleRegister(0));
+      break;
+    case kMips64BitcastLD:
+      __ dmtc1(i.InputRegister(0), i.OutputDoubleRegister());
+      break;
     case kMips64Float64ExtractLowWord32:
       __ FmoveLow(i.OutputRegister(), i.InputDoubleRegister(0));
       break;
     case kMips64Float64ExtractHighWord32:
       __ FmoveHigh(i.OutputRegister(), i.InputDoubleRegister(0));
       break;
     case kMips64Float64InsertLowWord32:
       __ FmoveLow(i.OutputDoubleRegister(), i.InputRegister(1));
       break;
     case kMips64Float64InsertHighWord32:
@@ skipping 703 matching lines @@
       padding_size -= v8::internal::Assembler::kInstrSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8