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

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

Index: src/compiler/mips64/code-generator-mips64.cc
diff --git a/src/compiler/mips64/code-generator-mips64.cc b/src/compiler/mips64/code-generator-mips64.cc
index debca20ca31bfe83b69c33237f5ccd9b1f99caf3..053434eec9a916f4e9eb287ffbb712002d70fc85 100644
--- a/src/compiler/mips64/code-generator-mips64.cc
+++ b/src/compiler/mips64/code-generator-mips64.cc
@@ -799,6 +799,12 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ 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;