[SubZero][MIPS32]: Add return registers for float/double types in lowerCall

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 1750 matching lines @@
     case IceType_i8:
     case IceType_i16:
     case IceType_i32:
       ReturnReg = makeReg(Dest->getType(), RegMIPS32::Reg_V0);
       break;
     case IceType_i64:
       ReturnReg = I32Reg(RegMIPS32::Reg_V0);
       ReturnRegHi = I32Reg(RegMIPS32::Reg_V1);
       break;
     case IceType_f32:
+      ReturnReg = makeReg(Dest->getType(), RegMIPS32::Reg_F0);
+      break;
     case IceType_f64:
-      UnimplementedLoweringError(this, Instr);
-      return;
+      ReturnReg = makeReg(IceType_f32, RegMIPS32::Reg_F0);
+      ReturnRegHi = makeReg(IceType_f32, RegMIPS32::Reg_F1);
+      break;
     case IceType_v4i1:
     case IceType_v8i1:
     case IceType_v16i1:
     case IceType_v16i8:
     case IceType_v8i16:
     case IceType_v4i32:
     case IceType_v4f32:
       UnimplementedLoweringError(this, Instr);
       return;
     }
@@ skipping 787 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