[Subzero][MIPS32] Implement bitcast operation for both 32-bit and 64-bit operands

src/IceInstMIPS32.cpp

 //===- subzero/src/IceInstMips32.cpp - Mips32 instruction implementation --===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 /// \file
@@ skipping 265 matching lines @@
   auto *Asm = Func->getAssembler<MIPS32::AssemblerMIPS32>();
   Asm->bindLocalLabel(this, Number);
 }
 
 InstMIPS32Call::InstMIPS32Call(Cfg *Func, Variable *Dest, Operand *CallTarget)
     : InstMIPS32(Func, InstMIPS32::Call, 1, Dest) {
   HasSideEffects = true;
   addSource(CallTarget);
 }
 
-InstMIPS32Mov::InstMIPS32Mov(Cfg *Func, Variable *Dest, Operand *Src)
+InstMIPS32Mov::InstMIPS32Mov(Cfg *Func, Variable *Dest, Operand *Src,
+                             Operand *Src2)
     : InstMIPS32(Func, InstMIPS32::Mov, 2, Dest) {
   auto *Dest64 = llvm::dyn_cast<Variable64On32>(Dest);
   auto *Src64 = llvm::dyn_cast<Variable64On32>(Src);
 
   assert(Dest64 == nullptr || Src64 == nullptr);
 
+  if (Dest->getType() == IceType_f64 && Src2 != nullptr) {
+    addSource(Src);
+    addSource(Src2);
+    return;
+  }
+
   if (Dest64 != nullptr) {
     // this-> is needed below because there is a parameter named Dest.
     this->Dest = Dest64->getLo();
     DestHi = Dest64->getHi();
   }
 
   if (Src64 == nullptr) {
     addSource(Src);
   } else {
     addSource(Src64->getLo());
@@ skipping 904 matching lines @@
   Asm->xor_(getDest(), getSrc(0), getSrc(1));
 }
 
 template <> void InstMIPS32Xori::emitIAS(const Cfg *Func) const {
   auto *Asm = Func->getAssembler<MIPS32::AssemblerMIPS32>();
   Asm->xori(getDest(), getSrc(0), Imm);
 }
 
 } // end of namespace MIPS32
 } // end of namespace Ice