Subzero: Make the register allocator more robust with -reg-use and -reg-exclude.

src/IceTargetLoweringARM32.cpp

 //===- subzero/src/IceTargetLoweringARM32.cpp - ARM32 lowering ------------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 324 matching lines @@
   TypeToRegisterSet[IceType_f32] = Float32Registers;
   TypeToRegisterSet[IceType_f64] = Float64Registers;
   TypeToRegisterSet[IceType_v4i1] = VectorRegisters;
   TypeToRegisterSet[IceType_v8i1] = VectorRegisters;
   TypeToRegisterSet[IceType_v16i1] = VectorRegisters;
   TypeToRegisterSet[IceType_v16i8] = VectorRegisters;
   TypeToRegisterSet[IceType_v8i16] = VectorRegisters;
   TypeToRegisterSet[IceType_v4i32] = VectorRegisters;
   TypeToRegisterSet[IceType_v4f32] = VectorRegisters;
 
+  for (size_t i = 0; i < llvm::array_lengthof(TypeToRegisterSet); ++i)
+    TypeToRegisterSetUnfiltered[i] = TypeToRegisterSet[i];
+
   filterTypeToRegisterSet(
       Ctx, RegARM32::Reg_NUM, TypeToRegisterSet,
       llvm::array_lengthof(TypeToRegisterSet), [](int32_t RegNum) -> IceString {
         // This function simply removes ", " from the register name.
         IceString Name = RegARM32::getRegName(RegNum);
         constexpr const char RegSeparator[] = ", ";
         constexpr size_t RegSeparatorWidth =
             llvm::array_lengthof(RegSeparator) - 1;
         for (size_t Pos = Name.find(RegSeparator); Pos != std::string::npos;
              Pos = Name.find(RegSeparator)) {
@@ skipping 6140 matching lines @@
       << ".eabi_attribute 68, 1   @ Tag_Virtualization_use\n";
   if (CPUFeatures.hasFeature(TargetARM32Features::HWDivArm)) {
     Str << ".eabi_attribute 44, 2   @ Tag_DIV_use\n";
   }
   // Technically R9 is used for TLS with Sandboxing, and we reserve it.
   // However, for compatibility with current NaCl LLVM, don't claim that.
   Str << ".eabi_attribute 14, 3   @ Tag_ABI_PCS_R9_use: Not used\n";
 }
 
 llvm::SmallBitVector TargetARM32::TypeToRegisterSet[RegARM32::RCARM32_NUM];
+llvm::SmallBitVector
+    TargetARM32::TypeToRegisterSetUnfiltered[RegARM32::RCARM32_NUM];
 llvm::SmallBitVector TargetARM32::RegisterAliases[RegARM32::Reg_NUM];
 
 } // end of namespace ARM32
 } // end of namespace Ice