[SubZero] Fix floating-point comparison for MIPS

src/IceTargetLoweringMIPS32.cpp

 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
 /// \brief Implements the TargetLoweringMIPS32 class, which consists almost
@@ skipping 3319 matching lines @@
 // Turn an i64 Phi instruction into a pair of i32 Phi instructions, to preserve
 // integrity of liveness analysis. Undef values are also turned into zeroes,
 // since loOperand() and hiOperand() don't expect Undef input.
 void TargetMIPS32::prelowerPhis() {
   PhiLowering::prelowerPhis32Bit<TargetMIPS32>(this, Context.getNode(), Func);
 }
 
 void TargetMIPS32::postLower() {
   if (Func->getOptLevel() == Opt_m1)
     return;
-  // TODO(rkotler): Find two-address non-SSA instructions where Dest==Src0,
-  // and set the IsDestRedefined flag to keep liveness analysis consistent.
-  UnimplementedError(getFlags());
+  markRedefinitions();
+  Context.availabilityUpdate();
 }
 
 void TargetMIPS32::makeRandomRegisterPermutation(
     llvm::SmallVectorImpl<RegNumT> &Permutation,
     const SmallBitVector &ExcludeRegisters, uint64_t Salt) const {
   (void)Permutation;
   (void)ExcludeRegisters;
   (void)Salt;
   UnimplementedError(getFlags());
 }
@@ skipping 377 matching lines @@
   Str << "\t.set\t"
       << "nomips16\n";
 }
 
 SmallBitVector TargetMIPS32::TypeToRegisterSet[RCMIPS32_NUM];
 SmallBitVector TargetMIPS32::TypeToRegisterSetUnfiltered[RCMIPS32_NUM];
 SmallBitVector TargetMIPS32::RegisterAliases[RegMIPS32::Reg_NUM];
 
 } // end of namespace MIPS32
 } // end of namespace Ice