diff --git a/compiler/dex/quick/arm/utility_arm.cc b/compiler/dex/quick/arm/utility_arm.cc
index a1a5ad1..0d5aa90 100644
--- a/compiler/dex/quick/arm/utility_arm.cc
+++ b/compiler/dex/quick/arm/utility_arm.cc
@@ -959,7 +959,7 @@
 
   // TODO: in future may need to differentiate Dalvik accesses w/ spills
   if (mem_ref_type_ == ResourceMask::kDalvikReg) {
-    DCHECK(r_base == rs_rARM_SP);
+    DCHECK_EQ(r_base, rs_rARM_SP);
     AnnotateDalvikRegAccess(load, displacement >> 2, true /* is_load */, r_dest.Is64Bit());
   }
   return load;
@@ -1088,7 +1088,7 @@
 
   // TODO: In future, may need to differentiate Dalvik & spill accesses
   if (mem_ref_type_ == ResourceMask::kDalvikReg) {
-    DCHECK(r_base == rs_rARM_SP);
+    DCHECK_EQ(r_base, rs_rARM_SP);
     AnnotateDalvikRegAccess(store, displacement >> 2, false /* is_load */, r_src.Is64Bit());
   }
   return store;
diff --git a/compiler/dex/quick/arm64/int_arm64.cc b/compiler/dex/quick/arm64/int_arm64.cc
index fc72e02..e57f99c 100644
--- a/compiler/dex/quick/arm64/int_arm64.cc
+++ b/compiler/dex/quick/arm64/int_arm64.cc
@@ -1663,7 +1663,7 @@
 
 void Arm64Mir2Lir::UnspillRegs(RegStorage base, uint32_t core_reg_mask, uint32_t fp_reg_mask,
                                int frame_size) {
-  DCHECK(base == rs_sp);
+  DCHECK_EQ(base, rs_sp);
   // Restore saves and drop stack frame.
   // 2 versions:
   //
diff --git a/compiler/dex/quick/arm64/utility_arm64.cc b/compiler/dex/quick/arm64/utility_arm64.cc
index fcd69ec..78a6df8 100644
--- a/compiler/dex/quick/arm64/utility_arm64.cc
+++ b/compiler/dex/quick/arm64/utility_arm64.cc
@@ -1266,7 +1266,7 @@
 
   // TODO: in future may need to differentiate Dalvik accesses w/ spills
   if (mem_ref_type_ == ResourceMask::kDalvikReg) {
-    DCHECK(r_base == rs_sp);
+    DCHECK_EQ(r_base, rs_sp);
     AnnotateDalvikRegAccess(load, displacement >> 2, true /* is_load */, r_dest.Is64Bit());
   }
   return load;
@@ -1357,7 +1357,7 @@
 
   // TODO: In future, may need to differentiate Dalvik & spill accesses.
   if (mem_ref_type_ == ResourceMask::kDalvikReg) {
-    DCHECK(r_base == rs_sp);
+    DCHECK_EQ(r_base, rs_sp);
     AnnotateDalvikRegAccess(store, displacement >> 2, false /* is_load */, r_src.Is64Bit());
   }
   return store;
diff --git a/compiler/dex/quick/mips/utility_mips.cc b/compiler/dex/quick/mips/utility_mips.cc
index 044972c..a7dc84f 100644
--- a/compiler/dex/quick/mips/utility_mips.cc
+++ b/compiler/dex/quick/mips/utility_mips.cc
@@ -544,7 +544,7 @@
   }
 
   if (mem_ref_type_ == ResourceMask::kDalvikReg) {
-    DCHECK(r_base == rs_rMIPS_SP);
+    DCHECK_EQ(r_base, rs_rMIPS_SP);
     AnnotateDalvikRegAccess(load, (displacement + (pair ? LOWORD_OFFSET : 0)) >> 2,
                             true /* is_load */, pair /* is64bit */);
     if (pair) {
@@ -646,7 +646,7 @@
   }
 
   if (mem_ref_type_ == ResourceMask::kDalvikReg) {
-    DCHECK(r_base == rs_rMIPS_SP);
+    DCHECK_EQ(r_base, rs_rMIPS_SP);
     AnnotateDalvikRegAccess(store, (displacement + (pair ? LOWORD_OFFSET : 0)) >> 2,
                             false /* is_load */, pair /* is64bit */);
     if (pair) {
diff --git a/compiler/dex/quick/x86/assemble_x86.cc b/compiler/dex/quick/x86/assemble_x86.cc
index ef55054..3933b21 100644
--- a/compiler/dex/quick/x86/assemble_x86.cc
+++ b/compiler/dex/quick/x86/assemble_x86.cc
@@ -677,7 +677,7 @@
     ++size;  // modrm
   }
   if (!modrm_is_reg_reg) {
-    if (has_sib || LowRegisterBits(raw_base) == rs_rX86_SP.GetRegNum()
+    if (has_sib || (LowRegisterBits(raw_base) == rs_rX86_SP_32.GetRegNum())
         || (cu_->target64 && entry->skeleton.prefix1 == THREAD_PREFIX)) {
       // SP requires a SIB byte.
       // GS access also needs a SIB byte for absolute adressing in 64-bit mode.
@@ -1010,9 +1010,9 @@
 void X86Mir2Lir::EmitModrmThread(uint8_t reg_or_opcode) {
   if (cu_->target64) {
     // Absolute adressing for GS access.
-    uint8_t modrm = (0 << 6) | (reg_or_opcode << 3) | rs_rX86_SP.GetRegNum();
+    uint8_t modrm = (0 << 6) | (reg_or_opcode << 3) | rs_rX86_SP_32.GetRegNum();
     code_buffer_.push_back(modrm);
-    uint8_t sib = (0/*TIMES_1*/ << 6) | (rs_rX86_SP.GetRegNum() << 3) | rs_rBP.GetRegNum();
+    uint8_t sib = (0/*TIMES_1*/ << 6) | (rs_rX86_SP_32.GetRegNum() << 3) | rs_rBP.GetRegNum();
     code_buffer_.push_back(sib);
   } else {
     uint8_t modrm = (0 << 6) | (reg_or_opcode << 3) | rs_rBP.GetRegNum();
@@ -1025,9 +1025,9 @@
   DCHECK_LT(base, 8);
   uint8_t modrm = (ModrmForDisp(base, disp) << 6) | (reg_or_opcode << 3) | base;
   code_buffer_.push_back(modrm);
-  if (base == rs_rX86_SP.GetRegNum()) {
+  if (base == rs_rX86_SP_32.GetRegNum()) {
     // Special SIB for SP base
-    code_buffer_.push_back(0 << 6 | rs_rX86_SP.GetRegNum() << 3 | rs_rX86_SP.GetRegNum());
+    code_buffer_.push_back(0 << 6 | rs_rX86_SP_32.GetRegNum() << 3 | rs_rX86_SP_32.GetRegNum());
   }
   EmitDisp(base, disp);
 }
@@ -1036,7 +1036,7 @@
                                   int scale, int32_t disp) {
   DCHECK_LT(RegStorage::RegNum(reg_or_opcode), 8);
   uint8_t modrm = (ModrmForDisp(base, disp) << 6) | RegStorage::RegNum(reg_or_opcode) << 3 |
-      rs_rX86_SP.GetRegNum();
+      rs_rX86_SP_32.GetRegNum();
   code_buffer_.push_back(modrm);
   DCHECK_LT(scale, 4);
   DCHECK_LT(RegStorage::RegNum(index), 8);
@@ -1584,7 +1584,7 @@
     DCHECK_EQ(0, entry->skeleton.extra_opcode1);
     DCHECK_EQ(0, entry->skeleton.extra_opcode2);
     uint8_t low_reg = LowRegisterBits(raw_reg);
-    uint8_t modrm = (2 << 6) | (low_reg << 3) | rs_rX86_SP.GetRegNum();
+    uint8_t modrm = (2 << 6) | (low_reg << 3) | rs_rX86_SP_32.GetRegNum();
     code_buffer_.push_back(modrm);
     DCHECK_LT(scale, 4);
     uint8_t low_base_or_table = LowRegisterBits(raw_base_or_table);
diff --git a/compiler/dex/quick/x86/call_x86.cc b/compiler/dex/quick/x86/call_x86.cc
index 497ef94..61dcc28 100644
--- a/compiler/dex/quick/x86/call_x86.cc
+++ b/compiler/dex/quick/x86/call_x86.cc
@@ -164,16 +164,20 @@
    * expanding the frame or flushing.  This leaves the utility
    * code with no spare temps.
    */
-  LockTemp(rs_rX86_ARG0);
-  LockTemp(rs_rX86_ARG1);
-  LockTemp(rs_rX86_ARG2);
+  const RegStorage arg0 = TargetReg32(kArg0);
+  const RegStorage arg1 = TargetReg32(kArg1);
+  const RegStorage arg2 = TargetReg32(kArg2);
+  LockTemp(arg0);
+  LockTemp(arg1);
+  LockTemp(arg2);
 
   /*
    * We can safely skip the stack overflow check if we're
    * a leaf *and* our frame size < fudge factor.
    */
-  InstructionSet isa =  cu_->target64 ? kX86_64 : kX86;
+  const InstructionSet isa =  cu_->target64 ? kX86_64 : kX86;
   bool skip_overflow_check = mir_graph_->MethodIsLeaf() && !FrameNeedsStackCheck(frame_size_, isa);
+  const RegStorage rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
 
   // If we doing an implicit stack overflow check, perform the load immediately
   // before the stack pointer is decremented and anything is saved.
@@ -182,12 +186,12 @@
     // Implicit stack overflow check.
     // test eax,[esp + -overflow]
     int overflow = GetStackOverflowReservedBytes(isa);
-    NewLIR3(kX86Test32RM, rs_rAX.GetReg(), rs_rX86_SP.GetReg(), -overflow);
+    NewLIR3(kX86Test32RM, rs_rAX.GetReg(), rs_rSP.GetReg(), -overflow);
     MarkPossibleStackOverflowException();
   }
 
   /* Build frame, return address already on stack */
-  stack_decrement_ = OpRegImm(kOpSub, rs_rX86_SP, frame_size_ -
+  stack_decrement_ = OpRegImm(kOpSub, rs_rSP, frame_size_ -
                               GetInstructionSetPointerSize(cu_->instruction_set));
 
   NewLIR0(kPseudoMethodEntry);
@@ -204,7 +208,8 @@
         m2l_->ResetRegPool();
         m2l_->ResetDefTracking();
         GenerateTargetLabel(kPseudoThrowTarget);
-        m2l_->OpRegImm(kOpAdd, rs_rX86_SP, sp_displace_);
+        const RegStorage local_rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
+        m2l_->OpRegImm(kOpAdd, local_rs_rSP, sp_displace_);
         m2l_->ClobberCallerSave();
         // Assumes codegen and target are in thumb2 mode.
         m2l_->CallHelper(RegStorage::InvalidReg(), kQuickThrowStackOverflow,
@@ -225,9 +230,9 @@
       // may have moved us outside of the reserved area at the end of the stack.
       // cmp rs_rX86_SP, fs:[stack_end_]; jcc throw_slowpath
       if (cu_->target64) {
-        OpRegThreadMem(kOpCmp, rs_rX86_SP, Thread::StackEndOffset<8>());
+        OpRegThreadMem(kOpCmp, rs_rX86_SP_64, Thread::StackEndOffset<8>());
       } else {
-        OpRegThreadMem(kOpCmp, rs_rX86_SP, Thread::StackEndOffset<4>());
+        OpRegThreadMem(kOpCmp, rs_rX86_SP_32, Thread::StackEndOffset<4>());
       }
       LIR* branch = OpCondBranch(kCondUlt, nullptr);
       AddSlowPath(
@@ -245,13 +250,13 @@
     setup_method_address_[0] = NewLIR1(kX86StartOfMethod, method_start.GetReg());
     int displacement = SRegOffset(base_of_code_->s_reg_low);
     // Native pointer - must be natural word size.
-    setup_method_address_[1] = StoreBaseDisp(rs_rX86_SP, displacement, method_start,
+    setup_method_address_[1] = StoreBaseDisp(rs_rSP, displacement, method_start,
                                              cu_->target64 ? k64 : k32, kNotVolatile);
   }
 
-  FreeTemp(rs_rX86_ARG0);
-  FreeTemp(rs_rX86_ARG1);
-  FreeTemp(rs_rX86_ARG2);
+  FreeTemp(arg0);
+  FreeTemp(arg1);
+  FreeTemp(arg2);
 }
 
 void X86Mir2Lir::GenExitSequence() {
@@ -266,7 +271,9 @@
   UnSpillCoreRegs();
   UnSpillFPRegs();
   /* Remove frame except for return address */
-  stack_increment_ = OpRegImm(kOpAdd, rs_rX86_SP, frame_size_ - GetInstructionSetPointerSize(cu_->instruction_set));
+  const RegStorage rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
+  stack_increment_ = OpRegImm(kOpAdd, rs_rSP,
+                              frame_size_ - GetInstructionSetPointerSize(cu_->instruction_set));
   NewLIR0(kX86Ret);
 }
 
diff --git a/compiler/dex/quick/x86/codegen_x86.h b/compiler/dex/quick/x86/codegen_x86.h
index 4412a1e..d57dffb 100644
--- a/compiler/dex/quick/x86/codegen_x86.h
+++ b/compiler/dex/quick/x86/codegen_x86.h
@@ -389,7 +389,7 @@
   LIR* InvokeTrampoline(OpKind op, RegStorage r_tgt, QuickEntrypointEnum trampoline) OVERRIDE;
 
  protected:
-  RegStorage TargetReg32(SpecialTargetRegister reg);
+  RegStorage TargetReg32(SpecialTargetRegister reg) const;
   // Casting of RegStorage
   RegStorage As32BitReg(RegStorage reg) {
     DCHECK(!reg.IsPair());
@@ -432,7 +432,7 @@
   LIR* StoreBaseIndexedDisp(RegStorage r_base, RegStorage r_index, int scale, int displacement,
                             RegStorage r_src, OpSize size, int opt_flags = 0);
 
-  RegStorage GetCoreArgMappingToPhysicalReg(int core_arg_num);
+  RegStorage GetCoreArgMappingToPhysicalReg(int core_arg_num) const;
 
   int AssignInsnOffsets();
   void AssignOffsets();
@@ -530,7 +530,7 @@
    * @brief Check if a register is byte addressable.
    * @returns true if a register is byte addressable.
    */
-  bool IsByteRegister(RegStorage reg);
+  bool IsByteRegister(RegStorage reg) const;
 
   void GenDivRemLongLit(RegLocation rl_dest, RegLocation rl_src, int64_t imm, bool is_div);
 
diff --git a/compiler/dex/quick/x86/fp_x86.cc b/compiler/dex/quick/x86/fp_x86.cc
index 33bb0ee..bc02eee 100755
--- a/compiler/dex/quick/x86/fp_x86.cc
+++ b/compiler/dex/quick/x86/fp_x86.cc
@@ -159,12 +159,13 @@
     } else {
       // It must have been register promoted if it is not a temp but is still in physical
       // register. Since we need it to be in memory to convert, we place it there now.
-      StoreBaseDisp(rs_rX86_SP, src_v_reg_offset, rl_src.reg, k64, kNotVolatile);
+      const RegStorage rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
+      StoreBaseDisp(rs_rSP, src_v_reg_offset, rl_src.reg, k64, kNotVolatile);
     }
   }
 
   // Push the source virtual register onto the x87 stack.
-  LIR *fild64 = NewLIR2NoDest(kX86Fild64M, rs_rX86_SP.GetReg(),
+  LIR *fild64 = NewLIR2NoDest(kX86Fild64M, rs_rX86_SP_32.GetReg(),
                               src_v_reg_offset + LOWORD_OFFSET);
   AnnotateDalvikRegAccess(fild64, (src_v_reg_offset + LOWORD_OFFSET) >> 2,
                           true /* is_load */, true /* is64bit */);
@@ -172,7 +173,7 @@
   // Now pop off x87 stack and store it in the destination VR's stack location.
   int opcode = is_double ? kX86Fstp64M : kX86Fstp32M;
   int displacement = is_double ? dest_v_reg_offset + LOWORD_OFFSET : dest_v_reg_offset;
-  LIR *fstp = NewLIR2NoDest(opcode, rs_rX86_SP.GetReg(), displacement);
+  LIR *fstp = NewLIR2NoDest(opcode, rs_rX86_SP_32.GetReg(), displacement);
   AnnotateDalvikRegAccess(fstp, displacement >> 2, false /* is_load */, is_double);
 
   /*
@@ -191,12 +192,13 @@
      * correct register class.
      */
     rl_result = EvalLoc(rl_dest, kFPReg, true);
+    const RegStorage rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
     if (is_double) {
-      LoadBaseDisp(rs_rX86_SP, dest_v_reg_offset, rl_result.reg, k64, kNotVolatile);
+      LoadBaseDisp(rs_rSP, dest_v_reg_offset, rl_result.reg, k64, kNotVolatile);
 
       StoreFinalValueWide(rl_dest, rl_result);
     } else {
-      Load32Disp(rs_rX86_SP, dest_v_reg_offset, rl_result.reg);
+      Load32Disp(rs_rSP, dest_v_reg_offset, rl_result.reg);
 
       StoreFinalValue(rl_dest, rl_result);
     }
@@ -366,6 +368,7 @@
   ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
 
   // If the source is in physical register, then put it in its location on stack.
+  const RegStorage rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
   if (rl_src1.location == kLocPhysReg) {
     RegisterInfo* reg_info = GetRegInfo(rl_src1.reg);
 
@@ -377,7 +380,7 @@
     } else {
       // It must have been register promoted if it is not a temp but is still in physical
       // register. Since we need it to be in memory to convert, we place it there now.
-      StoreBaseDisp(rs_rX86_SP, src1_v_reg_offset, rl_src1.reg, is_double ? k64 : k32,
+      StoreBaseDisp(rs_rSP, src1_v_reg_offset, rl_src1.reg, is_double ? k64 : k32,
                     kNotVolatile);
     }
   }
@@ -388,7 +391,7 @@
       FlushSpecificReg(reg_info);
       ResetDef(rl_src2.reg);
     } else {
-      StoreBaseDisp(rs_rX86_SP, src2_v_reg_offset, rl_src2.reg, is_double ? k64 : k32,
+      StoreBaseDisp(rs_rSP, src2_v_reg_offset, rl_src2.reg, is_double ? k64 : k32,
                     kNotVolatile);
     }
   }
@@ -396,12 +399,12 @@
   int fld_opcode = is_double ? kX86Fld64M : kX86Fld32M;
 
   // Push the source virtual registers onto the x87 stack.
-  LIR *fld_2 = NewLIR2NoDest(fld_opcode, rs_rX86_SP.GetReg(),
+  LIR *fld_2 = NewLIR2NoDest(fld_opcode, rs_rSP.GetReg(),
                              src2_v_reg_offset + LOWORD_OFFSET);
   AnnotateDalvikRegAccess(fld_2, (src2_v_reg_offset + LOWORD_OFFSET) >> 2,
                           true /* is_load */, is_double /* is64bit */);
 
-  LIR *fld_1 = NewLIR2NoDest(fld_opcode, rs_rX86_SP.GetReg(),
+  LIR *fld_1 = NewLIR2NoDest(fld_opcode, rs_rSP.GetReg(),
                              src1_v_reg_offset + LOWORD_OFFSET);
   AnnotateDalvikRegAccess(fld_1, (src1_v_reg_offset + LOWORD_OFFSET) >> 2,
                           true /* is_load */, is_double /* is64bit */);
@@ -430,7 +433,7 @@
   // Now store result in the destination VR's stack location.
   int displacement = dest_v_reg_offset + LOWORD_OFFSET;
   int opcode = is_double ? kX86Fst64M : kX86Fst32M;
-  LIR *fst = NewLIR2NoDest(opcode, rs_rX86_SP.GetReg(), displacement);
+  LIR *fst = NewLIR2NoDest(opcode, rs_rSP.GetReg(), displacement);
   AnnotateDalvikRegAccess(fst, displacement >> 2, false /* is_load */, is_double /* is64bit */);
 
   // Pop ST(1) and ST(0).
@@ -448,10 +451,10 @@
   if (rl_result.location == kLocPhysReg) {
     rl_result = EvalLoc(rl_dest, kFPReg, true);
     if (is_double) {
-      LoadBaseDisp(rs_rX86_SP, dest_v_reg_offset, rl_result.reg, k64, kNotVolatile);
+      LoadBaseDisp(rs_rSP, dest_v_reg_offset, rl_result.reg, k64, kNotVolatile);
       StoreFinalValueWide(rl_dest, rl_result);
     } else {
-      Load32Disp(rs_rX86_SP, dest_v_reg_offset, rl_result.reg);
+      Load32Disp(rs_rSP, dest_v_reg_offset, rl_result.reg);
       StoreFinalValue(rl_dest, rl_result);
     }
   }
@@ -639,7 +642,7 @@
     // Operate directly into memory.
     int displacement = SRegOffset(rl_dest.s_reg_low);
     ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
-    LIR *lir = NewLIR3(kX86And32MI, rs_rX86_SP.GetReg(), displacement, 0x7fffffff);
+    LIR *lir = NewLIR3(kX86And32MI, rs_rX86_SP_32.GetReg(), displacement, 0x7fffffff);
     AnnotateDalvikRegAccess(lir, displacement >> 2, false /*is_load */, false /* is_64bit */);
     AnnotateDalvikRegAccess(lir, displacement >> 2, true /* is_load */, false /* is_64bit*/);
     return true;
@@ -703,7 +706,7 @@
     // Operate directly into memory.
     int displacement = SRegOffset(rl_dest.s_reg_low);
     ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
-    LIR *lir = NewLIR3(kX86And32MI, rs_rX86_SP.GetReg(), displacement  + HIWORD_OFFSET, 0x7fffffff);
+    LIR *lir = NewLIR3(kX86And32MI, rs_rX86_SP_32.GetReg(), displacement  + HIWORD_OFFSET, 0x7fffffff);
     AnnotateDalvikRegAccess(lir, (displacement + HIWORD_OFFSET) >> 2, true /* is_load */, true /* is_64bit*/);
     AnnotateDalvikRegAccess(lir, (displacement + HIWORD_OFFSET) >> 2, false /*is_load */, true /* is_64bit */);
     return true;
diff --git a/compiler/dex/quick/x86/int_x86.cc b/compiler/dex/quick/x86/int_x86.cc
index 26465a5..781c128 100755
--- a/compiler/dex/quick/x86/int_x86.cc
+++ b/compiler/dex/quick/x86/int_x86.cc
@@ -1124,15 +1124,16 @@
     }
     ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
     const size_t push_offset = (push_si ? 4u : 0u) + (push_di ? 4u : 0u);
+    const RegStorage rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
     if (!obj_in_si && !obj_in_di) {
-      LoadWordDisp(rs_rX86_SP, SRegOffset(rl_src_obj.s_reg_low) + push_offset, rs_obj);
+      LoadWordDisp(rs_rSP, SRegOffset(rl_src_obj.s_reg_low) + push_offset, rs_obj);
       // Dalvik register annotation in LoadBaseIndexedDisp() used wrong offset. Fix it.
       DCHECK(!DECODE_ALIAS_INFO_WIDE(last_lir_insn_->flags.alias_info));
       int reg_id = DECODE_ALIAS_INFO_REG(last_lir_insn_->flags.alias_info) - push_offset / 4u;
       AnnotateDalvikRegAccess(last_lir_insn_, reg_id, true, false);
     }
     if (!off_in_si && !off_in_di) {
-      LoadWordDisp(rs_rX86_SP, SRegOffset(rl_src_offset.s_reg_low) + push_offset, rs_off);
+      LoadWordDisp(rs_rSP, SRegOffset(rl_src_offset.s_reg_low) + push_offset, rs_off);
       // Dalvik register annotation in LoadBaseIndexedDisp() used wrong offset. Fix it.
       DCHECK(!DECODE_ALIAS_INFO_WIDE(last_lir_insn_->flags.alias_info));
       int reg_id = DECODE_ALIAS_INFO_REG(last_lir_insn_->flags.alias_info) - push_offset / 4u;
@@ -1507,12 +1508,14 @@
     case 0:
       NewLIR2(kX86Xor32RR, dest.GetReg(), dest.GetReg());
       break;
-    case 1:
-      LoadBaseDisp(rs_rX86_SP, displacement, dest, k32, kNotVolatile);
+    case 1: {
+      const RegStorage rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
+      LoadBaseDisp(rs_rSP, displacement, dest, k32, kNotVolatile);
       break;
+    }
     default:
       m = NewLIR4(IS_SIMM8(val) ? kX86Imul32RMI8 : kX86Imul32RMI, dest.GetReg(),
-                  rs_rX86_SP.GetReg(), displacement, val);
+                  rs_rX86_SP_32.GetReg(), displacement, val);
       AnnotateDalvikRegAccess(m, displacement >> 2, true /* is_load */, true /* is_64bit */);
       break;
   }
@@ -1653,7 +1656,7 @@
     if (src1_in_reg) {
       NewLIR1(kX86Mul32DaR, rl_src1.reg.GetLowReg());
     } else {
-      LIR *m = NewLIR2(kX86Mul32DaM, rs_rX86_SP.GetReg(), displacement + LOWORD_OFFSET);
+      LIR *m = NewLIR2(kX86Mul32DaM, rs_rX86_SP_32.GetReg(), displacement + LOWORD_OFFSET);
       AnnotateDalvikRegAccess(m, (displacement + LOWORD_OFFSET) >> 2,
                               true /* is_load */, true /* is_64bit */);
     }
@@ -1719,12 +1722,13 @@
   // At this point, the VRs are in their home locations.
   bool src1_in_reg = rl_src1.location == kLocPhysReg;
   bool src2_in_reg = rl_src2.location == kLocPhysReg;
+  const RegStorage rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
 
   // ECX <- 1H
   if (src1_in_reg) {
     NewLIR2(kX86Mov32RR, rs_r1.GetReg(), rl_src1.reg.GetHighReg());
   } else {
-    LoadBaseDisp(rs_rX86_SP, SRegOffset(rl_src1.s_reg_low) + HIWORD_OFFSET, rs_r1, k32,
+    LoadBaseDisp(rs_rSP, SRegOffset(rl_src1.s_reg_low) + HIWORD_OFFSET, rs_r1, k32,
                  kNotVolatile);
   }
 
@@ -1735,7 +1739,7 @@
       NewLIR2(kX86Imul32RR, rs_r1.GetReg(), rl_src2.reg.GetLowReg());
     } else {
       int displacement = SRegOffset(rl_src2.s_reg_low);
-      LIR* m = NewLIR3(kX86Imul32RM, rs_r1.GetReg(), rs_rX86_SP.GetReg(),
+      LIR* m = NewLIR3(kX86Imul32RM, rs_r1.GetReg(), rs_rX86_SP_32.GetReg(),
                        displacement + LOWORD_OFFSET);
       AnnotateDalvikRegAccess(m, (displacement + LOWORD_OFFSET) >> 2,
                               true /* is_load */, true /* is_64bit */);
@@ -1748,7 +1752,7 @@
     if (src2_in_reg) {
       NewLIR2(kX86Mov32RR, rs_r0.GetReg(), rl_src2.reg.GetHighReg());
     } else {
-      LoadBaseDisp(rs_rX86_SP, SRegOffset(rl_src2.s_reg_low) + HIWORD_OFFSET, rs_r0, k32,
+      LoadBaseDisp(rs_rSP, SRegOffset(rl_src2.s_reg_low) + HIWORD_OFFSET, rs_r0, k32,
                    kNotVolatile);
     }
 
@@ -1757,7 +1761,7 @@
       NewLIR2(kX86Imul32RR, rs_r0.GetReg(), rl_src1.reg.GetLowReg());
     } else {
       int displacement = SRegOffset(rl_src1.s_reg_low);
-      LIR *m = NewLIR3(kX86Imul32RM, rs_r0.GetReg(), rs_rX86_SP.GetReg(),
+      LIR *m = NewLIR3(kX86Imul32RM, rs_r0.GetReg(), rs_rX86_SP_32.GetReg(),
                        displacement + LOWORD_OFFSET);
       AnnotateDalvikRegAccess(m, (displacement + LOWORD_OFFSET) >> 2,
                               true /* is_load */, true /* is_64bit */);
@@ -1768,7 +1772,7 @@
       NewLIR2(kX86Imul32RR, rs_r1.GetReg(), rl_src2.reg.GetLowReg());
     } else {
       int displacement = SRegOffset(rl_src2.s_reg_low);
-      LIR *m = NewLIR3(kX86Imul32RM, rs_r1.GetReg(), rs_rX86_SP.GetReg(),
+      LIR *m = NewLIR3(kX86Imul32RM, rs_r1.GetReg(), rs_rX86_SP_32.GetReg(),
                        displacement + LOWORD_OFFSET);
       AnnotateDalvikRegAccess(m, (displacement + LOWORD_OFFSET) >> 2,
                               true /* is_load */, true /* is_64bit */);
@@ -1782,7 +1786,7 @@
   if (src2_in_reg) {
     NewLIR2(kX86Mov32RR, rs_r0.GetReg(), rl_src2.reg.GetLowReg());
   } else {
-    LoadBaseDisp(rs_rX86_SP, SRegOffset(rl_src2.s_reg_low) + LOWORD_OFFSET, rs_r0, k32,
+    LoadBaseDisp(rs_rSP, SRegOffset(rl_src2.s_reg_low) + LOWORD_OFFSET, rs_r0, k32,
                  kNotVolatile);
   }
 
@@ -1791,7 +1795,7 @@
     NewLIR1(kX86Mul32DaR, rl_src1.reg.GetLowReg());
   } else {
     int displacement = SRegOffset(rl_src1.s_reg_low);
-    LIR *m = NewLIR2(kX86Mul32DaM, rs_rX86_SP.GetReg(), displacement + LOWORD_OFFSET);
+    LIR *m = NewLIR2(kX86Mul32DaM, rs_rX86_SP_32.GetReg(), displacement + LOWORD_OFFSET);
     AnnotateDalvikRegAccess(m, (displacement + LOWORD_OFFSET) >> 2,
                             true /* is_load */, true /* is_64bit */);
   }
@@ -1833,7 +1837,7 @@
   // RHS is in memory.
   DCHECK((rl_src.location == kLocDalvikFrame) ||
          (rl_src.location == kLocCompilerTemp));
-  int r_base = rs_rX86_SP.GetReg();
+  int r_base = rs_rX86_SP_32.GetReg();
   int displacement = SRegOffset(rl_src.s_reg_low);
 
   ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
@@ -1876,7 +1880,7 @@
 
   // Operate directly into memory.
   X86OpCode x86op = GetOpcode(op, rl_dest, rl_src, false);
-  int r_base = rs_rX86_SP.GetReg();
+  int r_base = rs_rX86_SP_32.GetReg();
   int displacement = SRegOffset(rl_dest.s_reg_low);
 
   ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
@@ -2106,7 +2110,7 @@
         ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
         int displacement = SRegOffset(rl_src.s_reg_low);
         // RDX:RAX = magic * numerator.
-        LIR *m = NewLIR2(kX86Imul64DaM, rs_rX86_SP.GetReg(), displacement);
+        LIR *m = NewLIR2(kX86Imul64DaM, rs_rX86_SP_32.GetReg(), displacement);
         AnnotateDalvikRegAccess(m, displacement >> 2,
                                 true /* is_load */, true /* is_64bit */);
       } else {
@@ -2723,7 +2727,7 @@
 
     if ((rl_dest.location == kLocDalvikFrame) ||
         (rl_dest.location == kLocCompilerTemp)) {
-      int r_base = rs_rX86_SP.GetReg();
+      int r_base = rs_rX86_SP_32.GetReg();
       int displacement = SRegOffset(rl_dest.s_reg_low);
 
       ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
@@ -2754,7 +2758,7 @@
   // Can we just do this into memory?
   if ((rl_dest.location == kLocDalvikFrame) ||
       (rl_dest.location == kLocCompilerTemp)) {
-    int r_base = rs_rX86_SP.GetReg();
+    int r_base = rs_rX86_SP_32.GetReg();
     int displacement = SRegOffset(rl_dest.s_reg_low);
 
     ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
@@ -3198,7 +3202,7 @@
   } else {
     int displacement = SRegOffset(rl_src.s_reg_low);
     ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
-    LIR *m = NewLIR3(kX86MovsxdRM, rl_result.reg.GetReg(), rs_rX86_SP.GetReg(),
+    LIR *m = NewLIR3(kX86MovsxdRM, rl_result.reg.GetReg(), rs_rX86_SP_32.GetReg(),
                      displacement + LOWORD_OFFSET);
     AnnotateDalvikRegAccess(m, (displacement + LOWORD_OFFSET) >> 2,
                             true /* is_load */, true /* is_64bit */);
diff --git a/compiler/dex/quick/x86/target_x86.cc b/compiler/dex/quick/x86/target_x86.cc
index 270a4e5..db2f272 100755
--- a/compiler/dex/quick/x86/target_x86.cc
+++ b/compiler/dex/quick/x86/target_x86.cc
@@ -141,27 +141,6 @@
 static constexpr ArrayRef<const RegStorage> xp_temps_32(xp_temps_arr_32);
 static constexpr ArrayRef<const RegStorage> xp_temps_64(xp_temps_arr_64);
 
-RegStorage rs_rX86_SP;
-
-RegStorage rs_rX86_ARG0;
-RegStorage rs_rX86_ARG1;
-RegStorage rs_rX86_ARG2;
-RegStorage rs_rX86_ARG3;
-RegStorage rs_rX86_ARG4;
-RegStorage rs_rX86_ARG5;
-RegStorage rs_rX86_FARG0;
-RegStorage rs_rX86_FARG1;
-RegStorage rs_rX86_FARG2;
-RegStorage rs_rX86_FARG3;
-RegStorage rs_rX86_FARG4;
-RegStorage rs_rX86_FARG5;
-RegStorage rs_rX86_FARG6;
-RegStorage rs_rX86_FARG7;
-RegStorage rs_rX86_RET0;
-RegStorage rs_rX86_RET1;
-RegStorage rs_rX86_INVOKE_TGT;
-RegStorage rs_rX86_COUNT;
-
 RegLocation X86Mir2Lir::LocCReturn() {
   return x86_loc_c_return;
 }
@@ -182,39 +161,94 @@
   return x86_loc_c_return_double;
 }
 
+// 32-bit reg storage locations for 32-bit targets.
+static const RegStorage RegStorage32FromSpecialTargetRegister_Target32[] {
+  RegStorage::InvalidReg(),  // kSelf - Thread pointer.
+  RegStorage::InvalidReg(),  // kSuspend - Used to reduce suspend checks for some targets.
+  RegStorage::InvalidReg(),  // kLr - no register as the return address is pushed on entry.
+  RegStorage::InvalidReg(),  // kPc - not exposed on X86 see kX86StartOfMethod.
+  rs_rX86_SP_32,             // kSp
+  rs_rAX,                    // kArg0
+  rs_rCX,                    // kArg1
+  rs_rDX,                    // kArg2
+  rs_rBX,                    // kArg3
+  RegStorage::InvalidReg(),  // kArg4
+  RegStorage::InvalidReg(),  // kArg5
+  RegStorage::InvalidReg(),  // kArg6
+  RegStorage::InvalidReg(),  // kArg7
+  rs_rAX,                    // kFArg0
+  rs_rCX,                    // kFArg1
+  rs_rDX,                    // kFArg2
+  rs_rBX,                    // kFArg3
+  RegStorage::InvalidReg(),  // kFArg4
+  RegStorage::InvalidReg(),  // kFArg5
+  RegStorage::InvalidReg(),  // kFArg6
+  RegStorage::InvalidReg(),  // kFArg7
+  RegStorage::InvalidReg(),  // kFArg8
+  RegStorage::InvalidReg(),  // kFArg9
+  RegStorage::InvalidReg(),  // kFArg10
+  RegStorage::InvalidReg(),  // kFArg11
+  RegStorage::InvalidReg(),  // kFArg12
+  RegStorage::InvalidReg(),  // kFArg13
+  RegStorage::InvalidReg(),  // kFArg14
+  RegStorage::InvalidReg(),  // kFArg15
+  rs_rAX,                    // kRet0
+  rs_rDX,                    // kRet1
+  rs_rAX,                    // kInvokeTgt
+  rs_rAX,                    // kHiddenArg - used to hold the method index before copying to fr0.
+  rs_fr0,                    // kHiddenFpArg
+  rs_rCX,                    // kCount
+};
+
+// 32-bit reg storage locations for 64-bit targets.
+static const RegStorage RegStorage32FromSpecialTargetRegister_Target64[] {
+  RegStorage::InvalidReg(),  // kSelf - Thread pointer.
+  RegStorage::InvalidReg(),  // kSuspend - Used to reduce suspend checks for some targets.
+  RegStorage::InvalidReg(),  // kLr - no register as the return address is pushed on entry.
+  RegStorage::InvalidReg(),  // kPc - TODO: RIP based addressing.
+  rs_rX86_SP_32,             // kSp
+  rs_rDI,                    // kArg0
+  rs_rSI,                    // kArg1
+  rs_rDX,                    // kArg2
+  rs_rCX,                    // kArg3
+  rs_r8,                     // kArg4
+  rs_r9,                     // kArg5
+  RegStorage::InvalidReg(),  // kArg6
+  RegStorage::InvalidReg(),  // kArg7
+  rs_fr0,                    // kFArg0
+  rs_fr1,                    // kFArg1
+  rs_fr2,                    // kFArg2
+  rs_fr3,                    // kFArg3
+  rs_fr4,                    // kFArg4
+  rs_fr5,                    // kFArg5
+  rs_fr6,                    // kFArg6
+  rs_fr7,                    // kFArg7
+  RegStorage::InvalidReg(),  // kFArg8
+  RegStorage::InvalidReg(),  // kFArg9
+  RegStorage::InvalidReg(),  // kFArg10
+  RegStorage::InvalidReg(),  // kFArg11
+  RegStorage::InvalidReg(),  // kFArg12
+  RegStorage::InvalidReg(),  // kFArg13
+  RegStorage::InvalidReg(),  // kFArg14
+  RegStorage::InvalidReg(),  // kFArg15
+  rs_rAX,                    // kRet0
+  rs_rDX,                    // kRet1
+  rs_rAX,                    // kInvokeTgt
+  rs_rAX,                    // kHiddenArg
+  RegStorage::InvalidReg(),  // kHiddenFpArg
+  rs_rCX,                    // kCount
+};
+static_assert(arraysize(RegStorage32FromSpecialTargetRegister_Target32) ==
+              arraysize(RegStorage32FromSpecialTargetRegister_Target64),
+              "Mismatch in RegStorage array sizes");
+
 // Return a target-dependent special register for 32-bit.
-RegStorage X86Mir2Lir::TargetReg32(SpecialTargetRegister reg) {
-  RegStorage res_reg = RegStorage::InvalidReg();
-  switch (reg) {
-    case kSelf: res_reg = RegStorage::InvalidReg(); break;
-    case kSuspend: res_reg =  RegStorage::InvalidReg(); break;
-    case kLr: res_reg =  RegStorage::InvalidReg(); break;
-    case kPc: res_reg =  RegStorage::InvalidReg(); break;
-    case kSp: res_reg =  rs_rX86_SP_32; break;  // This must be the concrete one, as _SP is target-
-                                                // specific size.
-    case kArg0: res_reg = rs_rX86_ARG0; break;
-    case kArg1: res_reg = rs_rX86_ARG1; break;
-    case kArg2: res_reg = rs_rX86_ARG2; break;
-    case kArg3: res_reg = rs_rX86_ARG3; break;
-    case kArg4: res_reg = rs_rX86_ARG4; break;
-    case kArg5: res_reg = rs_rX86_ARG5; break;
-    case kFArg0: res_reg = rs_rX86_FARG0; break;
-    case kFArg1: res_reg = rs_rX86_FARG1; break;
-    case kFArg2: res_reg = rs_rX86_FARG2; break;
-    case kFArg3: res_reg = rs_rX86_FARG3; break;
-    case kFArg4: res_reg = rs_rX86_FARG4; break;
-    case kFArg5: res_reg = rs_rX86_FARG5; break;
-    case kFArg6: res_reg = rs_rX86_FARG6; break;
-    case kFArg7: res_reg = rs_rX86_FARG7; break;
-    case kRet0: res_reg = rs_rX86_RET0; break;
-    case kRet1: res_reg = rs_rX86_RET1; break;
-    case kInvokeTgt: res_reg = rs_rX86_INVOKE_TGT; break;
-    case kHiddenArg: res_reg = rs_rAX; break;
-    case kHiddenFpArg: DCHECK(!cu_->target64); res_reg = rs_fr0; break;
-    case kCount: res_reg = rs_rX86_COUNT; break;
-    default: res_reg = RegStorage::InvalidReg();
-  }
-  return res_reg;
+RegStorage X86Mir2Lir::TargetReg32(SpecialTargetRegister reg) const {
+  DCHECK_EQ(RegStorage32FromSpecialTargetRegister_Target32[kCount], rs_rCX);
+  DCHECK_EQ(RegStorage32FromSpecialTargetRegister_Target64[kCount], rs_rCX);
+  DCHECK_LT(reg, arraysize(RegStorage32FromSpecialTargetRegister_Target32));
+  return cu_->target64 ? RegStorage32FromSpecialTargetRegister_Target64[reg]
+                       : RegStorage32FromSpecialTargetRegister_Target32[reg];
 }
 
 RegStorage X86Mir2Lir::TargetReg(SpecialTargetRegister reg) {
@@ -433,7 +467,7 @@
 RegStorage X86Mir2Lir::AllocateByteRegister() {
   RegStorage reg = AllocTypedTemp(false, kCoreReg);
   if (!cu_->target64) {
-    DCHECK_LT(reg.GetRegNum(), rs_rX86_SP.GetRegNum());
+    DCHECK_LT(reg.GetRegNum(), rs_rX86_SP_32.GetRegNum());
   }
   return reg;
 }
@@ -442,8 +476,8 @@
   return GetRegInfo(reg)->Master()->GetReg();
 }
 
-bool X86Mir2Lir::IsByteRegister(RegStorage reg) {
-  return cu_->target64 || reg.GetRegNum() < rs_rX86_SP.GetRegNum();
+bool X86Mir2Lir::IsByteRegister(RegStorage reg) const {
+  return cu_->target64 || reg.GetRegNum() < rs_rX86_SP_32.GetRegNum();
 }
 
 /* Clobber all regs that might be used by an external C call */
@@ -483,8 +517,8 @@
 
 RegLocation X86Mir2Lir::GetReturnWideAlt() {
   RegLocation res = LocCReturnWide();
-  DCHECK(res.reg.GetLowReg() == rs_rAX.GetReg());
-  DCHECK(res.reg.GetHighReg() == rs_rDX.GetReg());
+  DCHECK_EQ(res.reg.GetLowReg(), rs_rAX.GetReg());
+  DCHECK_EQ(res.reg.GetHighReg(), rs_rDX.GetReg());
   Clobber(rs_rAX);
   Clobber(rs_rDX);
   MarkInUse(rs_rAX);
@@ -503,41 +537,41 @@
 
 /* To be used when explicitly managing register use */
 void X86Mir2Lir::LockCallTemps() {
-  LockTemp(rs_rX86_ARG0);
-  LockTemp(rs_rX86_ARG1);
-  LockTemp(rs_rX86_ARG2);
-  LockTemp(rs_rX86_ARG3);
+  LockTemp(TargetReg32(kArg0));
+  LockTemp(TargetReg32(kArg1));
+  LockTemp(TargetReg32(kArg2));
+  LockTemp(TargetReg32(kArg3));
   if (cu_->target64) {
-    LockTemp(rs_rX86_ARG4);
-    LockTemp(rs_rX86_ARG5);
-    LockTemp(rs_rX86_FARG0);
-    LockTemp(rs_rX86_FARG1);
-    LockTemp(rs_rX86_FARG2);
-    LockTemp(rs_rX86_FARG3);
-    LockTemp(rs_rX86_FARG4);
-    LockTemp(rs_rX86_FARG5);
-    LockTemp(rs_rX86_FARG6);
-    LockTemp(rs_rX86_FARG7);
+    LockTemp(TargetReg32(kArg4));
+    LockTemp(TargetReg32(kArg5));
+    LockTemp(TargetReg32(kFArg0));
+    LockTemp(TargetReg32(kFArg1));
+    LockTemp(TargetReg32(kFArg2));
+    LockTemp(TargetReg32(kFArg3));
+    LockTemp(TargetReg32(kFArg4));
+    LockTemp(TargetReg32(kFArg5));
+    LockTemp(TargetReg32(kFArg6));
+    LockTemp(TargetReg32(kFArg7));
   }
 }
 
 /* To be used when explicitly managing register use */
 void X86Mir2Lir::FreeCallTemps() {
-  FreeTemp(rs_rX86_ARG0);
-  FreeTemp(rs_rX86_ARG1);
-  FreeTemp(rs_rX86_ARG2);
-  FreeTemp(rs_rX86_ARG3);
+  FreeTemp(TargetReg32(kArg0));
+  FreeTemp(TargetReg32(kArg1));
+  FreeTemp(TargetReg32(kArg2));
+  FreeTemp(TargetReg32(kArg3));
   if (cu_->target64) {
-    FreeTemp(rs_rX86_ARG4);
-    FreeTemp(rs_rX86_ARG5);
-    FreeTemp(rs_rX86_FARG0);
-    FreeTemp(rs_rX86_FARG1);
-    FreeTemp(rs_rX86_FARG2);
-    FreeTemp(rs_rX86_FARG3);
-    FreeTemp(rs_rX86_FARG4);
-    FreeTemp(rs_rX86_FARG5);
-    FreeTemp(rs_rX86_FARG6);
-    FreeTemp(rs_rX86_FARG7);
+    FreeTemp(TargetReg32(kArg4));
+    FreeTemp(TargetReg32(kArg5));
+    FreeTemp(TargetReg32(kFArg0));
+    FreeTemp(TargetReg32(kFArg1));
+    FreeTemp(TargetReg32(kFArg2));
+    FreeTemp(TargetReg32(kFArg3));
+    FreeTemp(TargetReg32(kFArg4));
+    FreeTemp(TargetReg32(kFArg5));
+    FreeTemp(TargetReg32(kFArg6));
+    FreeTemp(TargetReg32(kFArg7));
   }
 }
 
@@ -687,11 +721,14 @@
   }
   // Spill mask not including fake return address register
   uint32_t mask = core_spill_mask_ & ~(1 << rs_rRET.GetRegNum());
-  int offset = frame_size_ - (GetInstructionSetPointerSize(cu_->instruction_set) * num_core_spills_);
+  int offset =
+      frame_size_ - (GetInstructionSetPointerSize(cu_->instruction_set) * num_core_spills_);
   OpSize size = cu_->target64 ? k64 : k32;
+  const RegStorage rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
   for (int reg = 0; mask; mask >>= 1, reg++) {
     if (mask & 0x1) {
-      StoreBaseDisp(rs_rX86_SP, offset, cu_->target64 ? RegStorage::Solo64(reg) :  RegStorage::Solo32(reg),
+      StoreBaseDisp(rs_rSP, offset,
+                    cu_->target64 ? RegStorage::Solo64(reg) :  RegStorage::Solo32(reg),
                    size, kNotVolatile);
       offset += GetInstructionSetPointerSize(cu_->instruction_set);
     }
@@ -706,9 +743,10 @@
   uint32_t mask = core_spill_mask_ & ~(1 << rs_rRET.GetRegNum());
   int offset = frame_size_ - (GetInstructionSetPointerSize(cu_->instruction_set) * num_core_spills_);
   OpSize size = cu_->target64 ? k64 : k32;
+  const RegStorage rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
   for (int reg = 0; mask; mask >>= 1, reg++) {
     if (mask & 0x1) {
-      LoadBaseDisp(rs_rX86_SP, offset, cu_->target64 ? RegStorage::Solo64(reg) :  RegStorage::Solo32(reg),
+      LoadBaseDisp(rs_rSP, offset, cu_->target64 ? RegStorage::Solo64(reg) :  RegStorage::Solo32(reg),
                    size, kNotVolatile);
       offset += GetInstructionSetPointerSize(cu_->instruction_set);
     }
@@ -720,11 +758,12 @@
     return;
   }
   uint32_t mask = fp_spill_mask_;
-  int offset = frame_size_ - (GetInstructionSetPointerSize(cu_->instruction_set) * (num_fp_spills_ + num_core_spills_));
+  int offset = frame_size_ -
+      (GetInstructionSetPointerSize(cu_->instruction_set) * (num_fp_spills_ + num_core_spills_));
+  const RegStorage rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
   for (int reg = 0; mask; mask >>= 1, reg++) {
     if (mask & 0x1) {
-      StoreBaseDisp(rs_rX86_SP, offset, RegStorage::FloatSolo64(reg),
-                   k64, kNotVolatile);
+      StoreBaseDisp(rs_rSP, offset, RegStorage::FloatSolo64(reg), k64, kNotVolatile);
       offset += sizeof(double);
     }
   }
@@ -734,10 +773,12 @@
     return;
   }
   uint32_t mask = fp_spill_mask_;
-  int offset = frame_size_ - (GetInstructionSetPointerSize(cu_->instruction_set) * (num_fp_spills_ + num_core_spills_));
+  int offset = frame_size_ -
+      (GetInstructionSetPointerSize(cu_->instruction_set) * (num_fp_spills_ + num_core_spills_));
+  const RegStorage rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
   for (int reg = 0; mask; mask >>= 1, reg++) {
     if (mask & 0x1) {
-      LoadBaseDisp(rs_rX86_SP, offset, RegStorage::FloatSolo64(reg),
+      LoadBaseDisp(rs_rSP, offset, RegStorage::FloatSolo64(reg),
                    k64, kNotVolatile);
       offset += sizeof(double);
     }
@@ -783,49 +824,6 @@
           << " is wrong: expecting " << i << ", seeing "
           << static_cast<int>(X86Mir2Lir::EncodingMap[i].opcode);
   }
-  if (cu_->target64) {
-    rs_rX86_SP = rs_rX86_SP_64;
-
-    rs_rX86_ARG0 = rs_rDI;
-    rs_rX86_ARG1 = rs_rSI;
-    rs_rX86_ARG2 = rs_rDX;
-    rs_rX86_ARG3 = rs_rCX;
-    rs_rX86_ARG4 = rs_r8;
-    rs_rX86_ARG5 = rs_r9;
-    rs_rX86_FARG0 = rs_fr0;
-    rs_rX86_FARG1 = rs_fr1;
-    rs_rX86_FARG2 = rs_fr2;
-    rs_rX86_FARG3 = rs_fr3;
-    rs_rX86_FARG4 = rs_fr4;
-    rs_rX86_FARG5 = rs_fr5;
-    rs_rX86_FARG6 = rs_fr6;
-    rs_rX86_FARG7 = rs_fr7;
-    rs_rX86_INVOKE_TGT = rs_rDI;
-  } else {
-    rs_rX86_SP = rs_rX86_SP_32;
-
-    rs_rX86_ARG0 = rs_rAX;
-    rs_rX86_ARG1 = rs_rCX;
-    rs_rX86_ARG2 = rs_rDX;
-    rs_rX86_ARG3 = rs_rBX;
-    rs_rX86_ARG4 = RegStorage::InvalidReg();
-    rs_rX86_ARG5 = RegStorage::InvalidReg();
-    rs_rX86_FARG0 = rs_rAX;
-    rs_rX86_FARG1 = rs_rCX;
-    rs_rX86_FARG2 = rs_rDX;
-    rs_rX86_FARG3 = rs_rBX;
-    rs_rX86_FARG4 = RegStorage::InvalidReg();
-    rs_rX86_FARG5 = RegStorage::InvalidReg();
-    rs_rX86_FARG6 = RegStorage::InvalidReg();
-    rs_rX86_FARG7 = RegStorage::InvalidReg();
-    rs_rX86_INVOKE_TGT = rs_rAX;
-    // TODO(64): Initialize with invalid reg
-//    rX86_ARG4 = RegStorage::InvalidReg();
-//    rX86_ARG5 = RegStorage::InvalidReg();
-  }
-  rs_rX86_RET0 = rs_rAX;
-  rs_rX86_RET1 = rs_rDX;
-  rs_rX86_COUNT = rs_rCX;
 }
 
 Mir2Lir* X86CodeGenerator(CompilationUnit* const cu, MIRGraph* const mir_graph,
@@ -875,7 +873,7 @@
       (rl_dest.location == kLocCompilerTemp)) {
     int32_t val_lo = Low32Bits(value);
     int32_t val_hi = High32Bits(value);
-    int r_base = rs_rX86_SP.GetReg();
+    int r_base = rs_rX86_SP_32.GetReg();
     int displacement = SRegOffset(rl_dest.s_reg_low);
 
     ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
@@ -1327,7 +1325,7 @@
         // Load the start index from stack, remembering that we pushed EDI.
         int displacement = SRegOffset(rl_start.s_reg_low) + sizeof(uint32_t);
         ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
-        Load32Disp(rs_rX86_SP, displacement, rs_rDI);
+        Load32Disp(rs_rX86_SP_32, displacement, rs_rDI);
         // Dalvik register annotation in LoadBaseIndexedDisp() used wrong offset. Fix it.
         DCHECK(!DECODE_ALIAS_INFO_WIDE(last_lir_insn_->flags.alias_info));
         int reg_id = DECODE_ALIAS_INFO_REG(last_lir_insn_->flags.alias_info) - 1;
@@ -2264,7 +2262,7 @@
       StoreFinalValue(rl_dest, rl_result);
     } else {
       int displacement = SRegOffset(rl_result.s_reg_low);
-      LIR *l = NewLIR3(extr_opcode, rs_rX86_SP.GetReg(), displacement, vector_src.GetReg());
+      LIR *l = NewLIR3(extr_opcode, rs_rX86_SP_32.GetReg(), displacement, vector_src.GetReg());
       AnnotateDalvikRegAccess(l, displacement >> 2, true /* is_load */, is_wide /* is_64bit */);
       AnnotateDalvikRegAccess(l, displacement >> 2, false /* is_load */, is_wide /* is_64bit */);
     }
@@ -2462,18 +2460,14 @@
   return in_to_reg_storage_mapping_.Get(arg_num);
 }
 
-RegStorage X86Mir2Lir::GetCoreArgMappingToPhysicalReg(int core_arg_num) {
+RegStorage X86Mir2Lir::GetCoreArgMappingToPhysicalReg(int core_arg_num) const {
   // For the 32-bit internal ABI, the first 3 arguments are passed in registers.
   // Not used for 64-bit, TODO: Move X86_32 to the same framework
   switch (core_arg_num) {
-    case 0:
-      return rs_rX86_ARG1;
-    case 1:
-      return rs_rX86_ARG2;
-    case 2:
-      return rs_rX86_ARG3;
-    default:
-      return RegStorage::InvalidReg();
+    case 0: return TargetReg32(kArg1);
+    case 1: return TargetReg32(kArg2);
+    case 2: return TargetReg32(kArg3);
+    default: return RegStorage::InvalidReg();
   }
 }
 
@@ -2503,7 +2497,8 @@
   StoreValue(rl_method, rl_src);
   // If Method* has been promoted, explicitly flush
   if (rl_method.location == kLocPhysReg) {
-    StoreRefDisp(rs_rX86_SP, 0, As32BitReg(TargetReg(kArg0, kRef)), kNotVolatile);
+    const RegStorage rs_rSP = cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32;
+    StoreRefDisp(rs_rSP, 0, As32BitReg(TargetReg(kArg0, kRef)), kNotVolatile);
   }
 
   if (mir_graph_->GetNumOfInVRs() == 0) {
@@ -2540,9 +2535,9 @@
       } else {
         // Needs flush.
         if (t_loc->ref) {
-          StoreRefDisp(rs_rX86_SP, SRegOffset(start_vreg + i), reg, kNotVolatile);
+          StoreRefDisp(rs_rX86_SP_64, SRegOffset(start_vreg + i), reg, kNotVolatile);
         } else {
-          StoreBaseDisp(rs_rX86_SP, SRegOffset(start_vreg + i), reg, t_loc->wide ? k64 : k32,
+          StoreBaseDisp(rs_rX86_SP_64, SRegOffset(start_vreg + i), reg, t_loc->wide ? k64 : k32,
                         kNotVolatile);
         }
       }
@@ -2550,9 +2545,9 @@
       // If arriving in frame & promoted.
       if (t_loc->location == kLocPhysReg) {
         if (t_loc->ref) {
-          LoadRefDisp(rs_rX86_SP, SRegOffset(start_vreg + i), t_loc->reg, kNotVolatile);
+          LoadRefDisp(rs_rX86_SP_64, SRegOffset(start_vreg + i), t_loc->reg, kNotVolatile);
         } else {
-          LoadBaseDisp(rs_rX86_SP, SRegOffset(start_vreg + i), t_loc->reg,
+          LoadBaseDisp(rs_rX86_SP_64, SRegOffset(start_vreg + i), t_loc->reg,
                        t_loc->wide ? k64 : k32, kNotVolatile);
         }
       }
@@ -2578,16 +2573,16 @@
                                   uintptr_t direct_method, InvokeType type, bool skip_this) {
   if (!cu_->target64) {
     return Mir2Lir::GenDalvikArgsNoRange(info,
-                                  call_state, pcrLabel, next_call_insn,
-                                  target_method,
-                                  vtable_idx, direct_code,
-                                  direct_method, type, skip_this);
+                                         call_state, pcrLabel, next_call_insn,
+                                         target_method,
+                                         vtable_idx, direct_code,
+                                         direct_method, type, skip_this);
   }
   return GenDalvikArgsRange(info,
-                       call_state, pcrLabel, next_call_insn,
-                       target_method,
-                       vtable_idx, direct_code,
-                       direct_method, type, skip_this);
+                            call_state, pcrLabel, next_call_insn,
+                            target_method,
+                            vtable_idx, direct_code,
+                            direct_method, type, skip_this);
 }
 
 /*
@@ -2643,14 +2638,14 @@
         loc = UpdateLocWide(loc);
         if (loc.location == kLocPhysReg) {
           ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
-          StoreBaseDisp(rs_rX86_SP, SRegOffset(loc.s_reg_low), loc.reg, k64, kNotVolatile);
+          StoreBaseDisp(rs_rX86_SP_64, SRegOffset(loc.s_reg_low), loc.reg, k64, kNotVolatile);
         }
         next_arg += 2;
       } else {
         loc = UpdateLoc(loc);
         if (loc.location == kLocPhysReg) {
           ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
-          StoreBaseDisp(rs_rX86_SP, SRegOffset(loc.s_reg_low), loc.reg, k32, kNotVolatile);
+          StoreBaseDisp(rs_rX86_SP_64, SRegOffset(loc.s_reg_low), loc.reg, k32, kNotVolatile);
         }
         next_arg++;
       }
@@ -2705,23 +2700,23 @@
 
         ScopedMemRefType mem_ref_type2(this, ResourceMask::kDalvikReg);
         if (src_is_16b_aligned) {
-          ld1 = OpMovRegMem(temp, rs_rX86_SP, current_src_offset, kMovA128FP);
+          ld1 = OpMovRegMem(temp, rs_rX86_SP_64, current_src_offset, kMovA128FP);
         } else if (src_is_8b_aligned) {
-          ld1 = OpMovRegMem(temp, rs_rX86_SP, current_src_offset, kMovLo128FP);
-          ld2 = OpMovRegMem(temp, rs_rX86_SP, current_src_offset + (bytes_to_move >> 1),
+          ld1 = OpMovRegMem(temp, rs_rX86_SP_64, current_src_offset, kMovLo128FP);
+          ld2 = OpMovRegMem(temp, rs_rX86_SP_64, current_src_offset + (bytes_to_move >> 1),
                             kMovHi128FP);
         } else {
-          ld1 = OpMovRegMem(temp, rs_rX86_SP, current_src_offset, kMovU128FP);
+          ld1 = OpMovRegMem(temp, rs_rX86_SP_64, current_src_offset, kMovU128FP);
         }
 
         if (dest_is_16b_aligned) {
-          st1 = OpMovMemReg(rs_rX86_SP, current_dest_offset, temp, kMovA128FP);
+          st1 = OpMovMemReg(rs_rX86_SP_64, current_dest_offset, temp, kMovA128FP);
         } else if (dest_is_8b_aligned) {
-          st1 = OpMovMemReg(rs_rX86_SP, current_dest_offset, temp, kMovLo128FP);
-          st2 = OpMovMemReg(rs_rX86_SP, current_dest_offset + (bytes_to_move >> 1),
+          st1 = OpMovMemReg(rs_rX86_SP_64, current_dest_offset, temp, kMovLo128FP);
+          st2 = OpMovMemReg(rs_rX86_SP_64, current_dest_offset + (bytes_to_move >> 1),
                             temp, kMovHi128FP);
         } else {
-          st1 = OpMovMemReg(rs_rX86_SP, current_dest_offset, temp, kMovU128FP);
+          st1 = OpMovMemReg(rs_rX86_SP_64, current_dest_offset, temp, kMovU128FP);
         }
 
         // TODO If we could keep track of aliasing information for memory accesses that are wider
@@ -2758,8 +2753,8 @@
         RegStorage temp = TargetReg(kArg3, kNotWide);
 
         // Now load the argument VR and store to the outs.
-        Load32Disp(rs_rX86_SP, current_src_offset, temp);
-        Store32Disp(rs_rX86_SP, current_dest_offset, temp);
+        Load32Disp(rs_rX86_SP_64, current_src_offset, temp);
+        Store32Disp(rs_rX86_SP_64, current_dest_offset, temp);
       }
 
       current_src_offset += bytes_to_move;
@@ -2785,17 +2780,17 @@
           ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
           if (rl_arg.wide) {
             if (rl_arg.location == kLocPhysReg) {
-              StoreBaseDisp(rs_rX86_SP, out_offset, rl_arg.reg, k64, kNotVolatile);
+              StoreBaseDisp(rs_rX86_SP_64, out_offset, rl_arg.reg, k64, kNotVolatile);
             } else {
               LoadValueDirectWideFixed(rl_arg, regWide);
-              StoreBaseDisp(rs_rX86_SP, out_offset, regWide, k64, kNotVolatile);
+              StoreBaseDisp(rs_rX86_SP_64, out_offset, regWide, k64, kNotVolatile);
             }
           } else {
             if (rl_arg.location == kLocPhysReg) {
-              StoreBaseDisp(rs_rX86_SP, out_offset, rl_arg.reg, k32, kNotVolatile);
+              StoreBaseDisp(rs_rX86_SP_64, out_offset, rl_arg.reg, k32, kNotVolatile);
             } else {
               LoadValueDirectFixed(rl_arg, regSingle);
-              StoreBaseDisp(rs_rX86_SP, out_offset, regSingle, k32, kNotVolatile);
+              StoreBaseDisp(rs_rX86_SP_64, out_offset, regSingle, k32, kNotVolatile);
             }
           }
         }
diff --git a/compiler/dex/quick/x86/utility_x86.cc b/compiler/dex/quick/x86/utility_x86.cc
index cb9a24a..c1c79ca 100644
--- a/compiler/dex/quick/x86/utility_x86.cc
+++ b/compiler/dex/quick/x86/utility_x86.cc
@@ -230,7 +230,7 @@
         // TODO: there are several instances of this check.  A utility function perhaps?
         // TODO: Similar to Arm's reg < 8 check.  Perhaps add attribute checks to RegStorage?
         // Use shifts instead of a byte operand if the source can't be byte accessed.
-        if (r_src2.GetRegNum() >= rs_rX86_SP.GetRegNum()) {
+        if (r_src2.GetRegNum() >= rs_rX86_SP_32.GetRegNum()) {
           NewLIR2(is64Bit ? kX86Mov64RR : kX86Mov32RR, r_dest_src1.GetReg(), r_src2.GetReg());
           NewLIR2(is64Bit ? kX86Sal64RI : kX86Sal32RI, r_dest_src1.GetReg(), is64Bit ? 56 : 24);
           return NewLIR2(is64Bit ? kX86Sar64RI : kX86Sar32RI, r_dest_src1.GetReg(),
@@ -385,7 +385,7 @@
   }
   LIR *l = NewLIR3(opcode, r_dest.GetReg(), r_base.GetReg(), offset);
   if (mem_ref_type_ == ResourceMask::kDalvikReg) {
-    DCHECK(r_base == rs_rX86_SP);
+    DCHECK_EQ(r_base, cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32);
     AnnotateDalvikRegAccess(l, offset >> 2, true /* is_load */, false /* is_64bit */);
   }
   return l;
@@ -411,7 +411,7 @@
       LOG(FATAL) << "Bad case in OpMemReg " << op;
       break;
   }
-  LIR *l = NewLIR3(opcode, rs_rX86_SP.GetReg(), displacement, r_value);
+  LIR *l = NewLIR3(opcode, rs_rX86_SP_32.GetReg(), displacement, r_value);
   if (mem_ref_type_ == ResourceMask::kDalvikReg) {
     AnnotateDalvikRegAccess(l, displacement >> 2, true /* is_load */, is64Bit /* is_64bit */);
     AnnotateDalvikRegAccess(l, displacement >> 2, false /* is_load */, is64Bit /* is_64bit */);
@@ -437,7 +437,7 @@
       LOG(FATAL) << "Bad case in OpRegMem " << op;
       break;
   }
-  LIR *l = NewLIR3(opcode, r_dest.GetReg(), rs_rX86_SP.GetReg(), displacement);
+  LIR *l = NewLIR3(opcode, r_dest.GetReg(), rs_rX86_SP_32.GetReg(), displacement);
   if (mem_ref_type_ == ResourceMask::kDalvikReg) {
     AnnotateDalvikRegAccess(l, displacement >> 2, true /* is_load */, is64Bit /* is_64bit */);
   }
@@ -514,7 +514,7 @@
                      r_src.GetReg() /* index */, value /* scale */, 0 /* disp */);
     } else if (op == kOpAdd) {  // lea add special case
       return NewLIR5(r_dest.Is64Bit() ? kX86Lea64RA : kX86Lea32RA, r_dest.GetReg(),
-                     r_src.GetReg() /* base */, rs_rX86_SP.GetReg()/*r4sib_no_index*/ /* index */,
+                     r_src.GetReg() /* base */, rs_rX86_SP_32.GetReg()/*r4sib_no_index*/ /* index */,
                      0 /* scale */, value /* disp */);
     }
     OpRegCopy(r_dest, r_src);
@@ -705,7 +705,7 @@
       }
     }
     if (mem_ref_type_ == ResourceMask::kDalvikReg) {
-      DCHECK(r_base == rs_rX86_SP);
+      DCHECK_EQ(r_base, cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32);
       AnnotateDalvikRegAccess(load, (displacement + (pair ? LOWORD_OFFSET : 0)) >> 2,
                               true /* is_load */, is64bit);
       if (pair) {
@@ -870,7 +870,7 @@
       store2 = NewLIR3(opcode, r_base.GetReg(), displacement + HIWORD_OFFSET, r_src.GetHighReg());
     }
     if (mem_ref_type_ == ResourceMask::kDalvikReg) {
-      DCHECK(r_base == rs_rX86_SP);
+      DCHECK_EQ(r_base, cu_->target64 ? rs_rX86_SP_64 : rs_rX86_SP_32);
       AnnotateDalvikRegAccess(store, (displacement + (pair ? LOWORD_OFFSET : 0)) >> 2,
                               false /* is_load */, is64bit);
       if (pair) {
diff --git a/compiler/dex/quick/x86/x86_lir.h b/compiler/dex/quick/x86/x86_lir.h
index afdc244..76a67c4 100644
--- a/compiler/dex/quick/x86/x86_lir.h
+++ b/compiler/dex/quick/x86/x86_lir.h
@@ -234,7 +234,7 @@
 constexpr RegStorage rs_rBX = rs_r3;
 constexpr RegStorage rs_rX86_SP_64(RegStorage::kValid | r4sp_64);
 constexpr RegStorage rs_rX86_SP_32(RegStorage::kValid | r4sp_32);
-extern RegStorage rs_rX86_SP;
+static_assert(rs_rX86_SP_64.GetRegNum() == rs_rX86_SP_32.GetRegNum(), "Unexpected mismatch");
 constexpr RegStorage rs_r5(RegStorage::kValid | r5);
 constexpr RegStorage rs_r5q(RegStorage::kValid | r5q);
 constexpr RegStorage rs_rBP = rs_r5;
@@ -313,24 +313,8 @@
 constexpr RegStorage rs_xr14(RegStorage::kValid | xr14);
 constexpr RegStorage rs_xr15(RegStorage::kValid | xr15);
 
-extern RegStorage rs_rX86_ARG0;
-extern RegStorage rs_rX86_ARG1;
-extern RegStorage rs_rX86_ARG2;
-extern RegStorage rs_rX86_ARG3;
-extern RegStorage rs_rX86_ARG4;
-extern RegStorage rs_rX86_ARG5;
-extern RegStorage rs_rX86_FARG0;
-extern RegStorage rs_rX86_FARG1;
-extern RegStorage rs_rX86_FARG2;
-extern RegStorage rs_rX86_FARG3;
-extern RegStorage rs_rX86_FARG4;
-extern RegStorage rs_rX86_FARG5;
-extern RegStorage rs_rX86_FARG6;
-extern RegStorage rs_rX86_FARG7;
-extern RegStorage rs_rX86_RET0;
-extern RegStorage rs_rX86_RET1;
-extern RegStorage rs_rX86_INVOKE_TGT;
-extern RegStorage rs_rX86_COUNT;
+constexpr RegStorage rs_rX86_RET0 = rs_rAX;
+constexpr RegStorage rs_rX86_RET1 = rs_rDX;
 
 // RegisterLocation templates return values (r_V0, or r_V0/r_V1).
 const RegLocation x86_loc_c_return