[mips] Define two subclasses of MipsTargetLowering. Mips16TargetLowering is for

mips16 and MipsSETargetLowering is for mips32/64. 

No functionality changes.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176917 91177308-0d34-0410-b5e6-96231b3b80d8

9 files changed, 1106 insertions, 878 deletions

diff --git a/lib/Target/Mips/CMakeLists.txt b/lib/Target/Mips/CMakeLists.txt
index 58aa1be34d..7c41e355dc 100644
--- a/lib/Target/Mips/CMakeLists.txt
+++ b/lib/Target/Mips/CMakeLists.txt
@@ -16,6 +16,7 @@ add_public_tablegen_target(MipsCommonTableGen)
 add_llvm_target(MipsCodeGen
   Mips16FrameLowering.cpp
   Mips16InstrInfo.cpp
+  Mips16ISelLowering.cpp
   Mips16RegisterInfo.cpp
   MipsAnalyzeImmediate.cpp
   MipsAsmPrinter.cpp
@@ -33,6 +34,7 @@ add_llvm_target(MipsCodeGen
   MipsRegisterInfo.cpp
   MipsSEFrameLowering.cpp
   MipsSEInstrInfo.cpp
+  MipsSEISelLowering.cpp
   MipsSERegisterInfo.cpp
   MipsSubtarget.cpp
   MipsTargetMachine.cpp
diff --git a/lib/Target/Mips/Mips16ISelLowering.cpp b/lib/Target/Mips/Mips16ISelLowering.cpp
new file mode 100644
index 0000000000..6de62cfab3
--- /dev/null
+++ b/lib/Target/Mips/Mips16ISelLowering.cpp
@@ -0,0 +1,681 @@
+//===-- Mips16ISelLowering.h - Mips16 DAG Lowering Interface ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Subclass of MipsTargetLowering specialized for mips16.
+//
+//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "mips-lower"
+#include "Mips16ISelLowering.h"
+#include "MipsRegisterInfo.h"
+#include "MCTargetDesc/MipsBaseInfo.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include <set>
+
+using namespace llvm;
+
+static cl::opt<bool>
+Mips16HardFloat("mips16-hard-float", cl::NotHidden,
+                cl::desc("MIPS: mips16 hard float enable."),
+                cl::init(false));
+
+static cl::opt<bool> DontExpandCondPseudos16(
+  "mips16-dont-expand-cond-pseudo",
+  cl::init(false),
+  cl::desc("Dont expand conditional move related "
+           "pseudos for Mips 16"),
+  cl::Hidden);
+
+namespace {
+  std::set<const char*, MipsTargetLowering::LTStr> NoHelperNeeded;
+}
+
+Mips16TargetLowering::Mips16TargetLowering(MipsTargetMachine &TM)
+  : MipsTargetLowering(TM) {
+  // Set up the register classes
+  addRegisterClass(MVT::i32, &Mips::CPU16RegsRegClass);
+
+  if (Mips16HardFloat)
+    setMips16HardFloatLibCalls();
+
+  setOperationAction(ISD::MEMBARRIER,         MVT::Other, Expand);
+  setOperationAction(ISD::ATOMIC_FENCE,       MVT::Other, Expand);
+  setOperationAction(ISD::ATOMIC_CMP_SWAP,    MVT::i32,   Expand);
+  setOperationAction(ISD::ATOMIC_SWAP,        MVT::i32,   Expand);
+  setOperationAction(ISD::ATOMIC_LOAD_ADD,    MVT::i32,   Expand);
+  setOperationAction(ISD::ATOMIC_LOAD_SUB,    MVT::i32,   Expand);
+  setOperationAction(ISD::ATOMIC_LOAD_AND,    MVT::i32,   Expand);
+  setOperationAction(ISD::ATOMIC_LOAD_OR,     MVT::i32,   Expand);
+  setOperationAction(ISD::ATOMIC_LOAD_XOR,    MVT::i32,   Expand);
+  setOperationAction(ISD::ATOMIC_LOAD_NAND,   MVT::i32,   Expand);
+  setOperationAction(ISD::ATOMIC_LOAD_MIN,    MVT::i32,   Expand);
+  setOperationAction(ISD::ATOMIC_LOAD_MAX,    MVT::i32,   Expand);
+  setOperationAction(ISD::ATOMIC_LOAD_UMIN,   MVT::i32,   Expand);
+  setOperationAction(ISD::ATOMIC_LOAD_UMAX,   MVT::i32,   Expand);
+
+  computeRegisterProperties();
+}
+
+const MipsTargetLowering *
+llvm::createMips16TargetLowering(MipsTargetMachine &TM) {
+  return new Mips16TargetLowering(TM);
+}
+
+bool
+Mips16TargetLowering::allowsUnalignedMemoryAccesses(EVT VT, bool *Fast) const {
+  return false;
+}
+
+MachineBasicBlock *
+Mips16TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
+                                                  MachineBasicBlock *BB) const {
+  switch (MI->getOpcode()) {
+  default:
+    return MipsTargetLowering::EmitInstrWithCustomInserter(MI, BB);
+  case Mips::SelBeqZ:
+    return emitSel16(Mips::BeqzRxImm16, MI, BB);
+  case Mips::SelBneZ:
+    return emitSel16(Mips::BnezRxImm16, MI, BB);
+  case Mips::SelTBteqZCmpi:
+    return emitSeliT16(Mips::BteqzX16, Mips::CmpiRxImmX16, MI, BB);
+  case Mips::SelTBteqZSlti:
+    return emitSeliT16(Mips::BteqzX16, Mips::SltiRxImmX16, MI, BB);
+  case Mips::SelTBteqZSltiu:
+    return emitSeliT16(Mips::BteqzX16, Mips::SltiuRxImmX16, MI, BB);
+  case Mips::SelTBtneZCmpi:
+    return emitSeliT16(Mips::BtnezX16, Mips::CmpiRxImmX16, MI, BB);
+  case Mips::SelTBtneZSlti:
+    return emitSeliT16(Mips::BtnezX16, Mips::SltiRxImmX16, MI, BB);
+  case Mips::SelTBtneZSltiu:
+    return emitSeliT16(Mips::BtnezX16, Mips::SltiuRxImmX16, MI, BB);
+  case Mips::SelTBteqZCmp:
+    return emitSelT16(Mips::BteqzX16, Mips::CmpRxRy16, MI, BB);
+  case Mips::SelTBteqZSlt:
+    return emitSelT16(Mips::BteqzX16, Mips::SltRxRy16, MI, BB);
+  case Mips::SelTBteqZSltu:
+    return emitSelT16(Mips::BteqzX16, Mips::SltuRxRy16, MI, BB);
+  case Mips::SelTBtneZCmp:
+    return emitSelT16(Mips::BtnezX16, Mips::CmpRxRy16, MI, BB);
+  case Mips::SelTBtneZSlt:
+    return emitSelT16(Mips::BtnezX16, Mips::SltRxRy16, MI, BB);
+  case Mips::SelTBtneZSltu:
+    return emitSelT16(Mips::BtnezX16, Mips::SltuRxRy16, MI, BB);
+  case Mips::BteqzT8CmpX16:
+    return emitFEXT_T8I816_ins(Mips::BteqzX16, Mips::CmpRxRy16, MI, BB);
+  case Mips::BteqzT8SltX16:
+    return emitFEXT_T8I816_ins(Mips::BteqzX16, Mips::SltRxRy16, MI, BB);
+  case Mips::BteqzT8SltuX16:
+    // TBD: figure out a way to get this or remove the instruction
+    // altogether.
+    return emitFEXT_T8I816_ins(Mips::BteqzX16, Mips::SltuRxRy16, MI, BB);
+  case Mips::BtnezT8CmpX16:
+    return emitFEXT_T8I816_ins(Mips::BtnezX16, Mips::CmpRxRy16, MI, BB);
+  case Mips::BtnezT8SltX16:
+    return emitFEXT_T8I816_ins(Mips::BtnezX16, Mips::SltRxRy16, MI, BB);
+  case Mips::BtnezT8SltuX16:
+    // TBD: figure out a way to get this or remove the instruction
+    // altogether.
+    return emitFEXT_T8I816_ins(Mips::BtnezX16, Mips::SltuRxRy16, MI, BB);
+  case Mips::BteqzT8CmpiX16: return emitFEXT_T8I8I16_ins(
+    Mips::BteqzX16, Mips::CmpiRxImm16, Mips::CmpiRxImmX16, MI, BB);
+  case Mips::BteqzT8SltiX16: return emitFEXT_T8I8I16_ins(
+    Mips::BteqzX16, Mips::SltiRxImm16, Mips::SltiRxImmX16, MI, BB);
+  case Mips::BteqzT8SltiuX16: return emitFEXT_T8I8I16_ins(
+    Mips::BteqzX16, Mips::SltiuRxImm16, Mips::SltiuRxImmX16, MI, BB);
+  case Mips::BtnezT8CmpiX16: return emitFEXT_T8I8I16_ins(
+    Mips::BtnezX16, Mips::CmpiRxImm16, Mips::CmpiRxImmX16, MI, BB);
+  case Mips::BtnezT8SltiX16: return emitFEXT_T8I8I16_ins(
+    Mips::BtnezX16, Mips::SltiRxImm16, Mips::SltiRxImmX16, MI, BB);
+  case Mips::BtnezT8SltiuX16: return emitFEXT_T8I8I16_ins(
+    Mips::BtnezX16, Mips::SltiuRxImm16, Mips::SltiuRxImmX16, MI, BB);
+    break;
+  case Mips::SltCCRxRy16:
+    return emitFEXT_CCRX16_ins(Mips::SltRxRy16, MI, BB);
+    break;
+  case Mips::SltiCCRxImmX16:
+    return emitFEXT_CCRXI16_ins
+      (Mips::SltiRxImm16, Mips::SltiRxImmX16, MI, BB);
+  case Mips::SltiuCCRxImmX16:
+    return emitFEXT_CCRXI16_ins
+      (Mips::SltiuRxImm16, Mips::SltiuRxImmX16, MI, BB);
+  case Mips::SltuCCRxRy16:
+    return emitFEXT_CCRX16_ins
+      (Mips::SltuRxRy16, MI, BB);
+  }
+}
+
+bool Mips16TargetLowering::
+isEligibleForTailCallOptimization(const MipsCC &MipsCCInfo,
+                                  unsigned NextStackOffset,
+                                  const MipsFunctionInfo& FI) const {
+  // No tail call optimization for mips16.
+  return false;
+}
+
+void Mips16TargetLowering::setMips16LibcallName
+  (RTLIB::Libcall L, const char *Name) {
+  setLibcallName(L, Name);
+  NoHelperNeeded.insert(Name);
+}
+
+void Mips16TargetLowering::setMips16HardFloatLibCalls() {
+  setMips16LibcallName(RTLIB::ADD_F32, "__mips16_addsf3");
+  setMips16LibcallName(RTLIB::ADD_F64, "__mips16_adddf3");
+  setMips16LibcallName(RTLIB::SUB_F32, "__mips16_subsf3");
+  setMips16LibcallName(RTLIB::SUB_F64, "__mips16_subdf3");
+  setMips16LibcallName(RTLIB::MUL_F32, "__mips16_mulsf3");
+  setMips16LibcallName(RTLIB::MUL_F64, "__mips16_muldf3");
+  setMips16LibcallName(RTLIB::DIV_F32, "__mips16_divsf3");
+  setMips16LibcallName(RTLIB::DIV_F64, "__mips16_divdf3");
+  setMips16LibcallName(RTLIB::FPEXT_F32_F64, "__mips16_extendsfdf2");
+  setMips16LibcallName(RTLIB::FPROUND_F64_F32, "__mips16_truncdfsf2");
+  setMips16LibcallName(RTLIB::FPTOSINT_F32_I32, "__mips16_fix_truncsfsi");
+  setMips16LibcallName(RTLIB::FPTOSINT_F64_I32, "__mips16_fix_truncdfsi");
+  setMips16LibcallName(RTLIB::SINTTOFP_I32_F32, "__mips16_floatsisf");
+  setMips16LibcallName(RTLIB::SINTTOFP_I32_F64, "__mips16_floatsidf");
+  setMips16LibcallName(RTLIB::UINTTOFP_I32_F32, "__mips16_floatunsisf");
+  setMips16LibcallName(RTLIB::UINTTOFP_I32_F64, "__mips16_floatunsidf");
+  setMips16LibcallName(RTLIB::OEQ_F32, "__mips16_eqsf2");
+  setMips16LibcallName(RTLIB::OEQ_F64, "__mips16_eqdf2");
+  setMips16LibcallName(RTLIB::UNE_F32, "__mips16_nesf2");
+  setMips16LibcallName(RTLIB::UNE_F64, "__mips16_nedf2");
+  setMips16LibcallName(RTLIB::OGE_F32, "__mips16_gesf2");
+  setMips16LibcallName(RTLIB::OGE_F64, "__mips16_gedf2");
+  setMips16LibcallName(RTLIB::OLT_F32, "__mips16_ltsf2");
+  setMips16LibcallName(RTLIB::OLT_F64, "__mips16_ltdf2");
+  setMips16LibcallName(RTLIB::OLE_F32, "__mips16_lesf2");
+  setMips16LibcallName(RTLIB::OLE_F64, "__mips16_ledf2");
+  setMips16LibcallName(RTLIB::OGT_F32, "__mips16_gtsf2");
+  setMips16LibcallName(RTLIB::OGT_F64, "__mips16_gtdf2");
+  setMips16LibcallName(RTLIB::UO_F32, "__mips16_unordsf2");
+  setMips16LibcallName(RTLIB::UO_F64, "__mips16_unorddf2");
+  setMips16LibcallName(RTLIB::O_F32, "__mips16_unordsf2");
+  setMips16LibcallName(RTLIB::O_F64, "__mips16_unorddf2");
+}
+
+
+//
+// The Mips16 hard float is a crazy quilt inherited from gcc. I have a much
+// cleaner way to do all of this but it will have to wait until the traditional
+// gcc mechanism is completed.
+//
+// For Pic, in order for Mips16 code to call Mips32 code which according the abi
+// have either arguments or returned values placed in floating point registers,
+// we use a set of helper functions. (This includes functions which return type
+//  complex which on Mips are returned in a pair of floating point registers).
+//
+// This is an encoding that we inherited from gcc.
+// In Mips traditional O32, N32 ABI, floating point numbers are passed in
+// floating point argument registers 1,2 only when the first and optionally
+// the second arguments are float (sf) or double (df).
+// For Mips16 we are only concerned with the situations where floating point
+// arguments are being passed in floating point registers by the ABI, because
+// Mips16 mode code cannot execute floating point instructions to load those
+// values and hence helper functions are needed.
+// The possibilities are (), (sf), (sf, sf), (sf, df), (df), (df, sf), (df, df)
+// the helper function suffixs for these are:
+//                        0,  1,    5,        9,         2,   6,        10
+// this suffix can then be calculated as follows:
+// for a given argument Arg:
+//     Arg1x, Arg2x = 1 :  Arg is sf
+//                    2 :  Arg is df
+//                    0:   Arg is neither sf or df
+// So this stub is the string for number Arg1x + Arg2x*4.
+// However not all numbers between 0 and 10 are possible, we check anyway and
+// assert if the impossible exists.
+//
+
+unsigned int Mips16TargetLowering::getMips16HelperFunctionStubNumber
+  (ArgListTy &Args) const {
+  unsigned int resultNum = 0;
+  if (Args.size() >= 1) {
+    Type *t = Args[0].Ty;
+    if (t->isFloatTy()) {
+      resultNum = 1;
+    }
+    else if (t->isDoubleTy()) {
+      resultNum = 2;
+    }
+  }
+  if (resultNum) {
+    if (Args.size() >=2) {
+      Type *t = Args[1].Ty;
+      if (t->isFloatTy()) {
+        resultNum += 4;
+      }
+      else if (t->isDoubleTy()) {
+        resultNum += 8;
+      }
+    }
+  }
+  return resultNum;
+}
+
+//
+// prefixs are attached to stub numbers depending on the return type .
+// return type: float  sf_
+//              double df_
+//              single complex sc_
+//              double complext dc_
+//              others  NO PREFIX
+//
+//
+// The full name of a helper function is__mips16_call_stub +
+//    return type dependent prefix + stub number
+//
+//
+// This is something that probably should be in a different source file and
+// perhaps done differently but my main purpose is to not waste runtime
+// on something that we can enumerate in the source. Another possibility is
+// to have a python script to generate these mapping tables. This will do
+// for now. There are a whole series of helper function mapping arrays, one
+// for each return type class as outlined above. There there are 11 possible
+//  entries. Ones with 0 are ones which should never be selected
+//
+// All the arrays are similar except for ones which return neither
+// sf, df, sc, dc, in which only care about ones which have sf or df as a
+// first parameter.
+//
+#define P_ "__mips16_call_stub_"
+#define MAX_STUB_NUMBER 10
+#define T1 P "1", P "2", 0, 0, P "5", P "6", 0, 0, P "9", P "10"
+#define T P "0" , T1
+#define P P_
+static char const * vMips16Helper[MAX_STUB_NUMBER+1] =
+  {0, T1 };
+#undef P
+#define P P_ "sf_"
+static char const * sfMips16Helper[MAX_STUB_NUMBER+1] =
+  { T };
+#undef P
+#define P P_ "df_"
+static char const * dfMips16Helper[MAX_STUB_NUMBER+1] =
+  { T };
+#undef P
+#define P P_ "sc_"
+static char const * scMips16Helper[MAX_STUB_NUMBER+1] =
+  { T };
+#undef P
+#define P P_ "dc_"
+static char const * dcMips16Helper[MAX_STUB_NUMBER+1] =
+  { T };
+#undef P
+#undef P_
+
+
+const char* Mips16TargetLowering::
+  getMips16HelperFunction
+    (Type* RetTy, ArgListTy &Args, bool &needHelper) const {
+  const unsigned int stubNum = getMips16HelperFunctionStubNumber(Args);
+#ifndef NDEBUG
+  const unsigned int maxStubNum = 10;
+  assert(stubNum <= maxStubNum);
+  const bool validStubNum[maxStubNum+1] =
+    {true, true, true, false, false, true, true, false, false, true, true};
+  assert(validStubNum[stubNum]);
+#endif
+  const char *result;
+  if (RetTy->isFloatTy()) {
+    result = sfMips16Helper[stubNum];
+  }
+  else if (RetTy ->isDoubleTy()) {
+    result = dfMips16Helper[stubNum];
+  }
+  else if (RetTy->isStructTy()) {
+    // check if it's complex
+    if (RetTy->getNumContainedTypes() == 2) {
+      if ((RetTy->getContainedType(0)->isFloatTy()) &&
+          (RetTy->getContainedType(1)->isFloatTy())) {
+        result = scMips16Helper[stubNum];
+      }
+      else if ((RetTy->getContainedType(0)->isDoubleTy()) &&
+               (RetTy->getContainedType(1)->isDoubleTy())) {
+        result = dcMips16Helper[stubNum];
+      }
+      else {
+        llvm_unreachable("Uncovered condition");
+      }
+    }
+    else {
+      llvm_unreachable("Uncovered condition");
+    }
+  }
+  else {
+    if (stubNum == 0) {
+      needHelper = false;
+      return "";
+    }
+    result = vMips16Helper[stubNum];
+  }
+  needHelper = true;
+  return result;
+}
+
+void Mips16TargetLowering::
+getOpndList(SmallVectorImpl<SDValue> &Ops,
+            std::deque< std::pair<unsigned, SDValue> > &RegsToPass,
+            bool IsPICCall, bool GlobalOrExternal, bool InternalLinkage,
+            CallLoweringInfo &CLI, SDValue Callee, SDValue Chain) const {
+  SelectionDAG &DAG = CLI.DAG;
+  const char* Mips16HelperFunction = 0;
+  bool NeedMips16Helper = false;
+
+  if (getTargetMachine().Options.UseSoftFloat && Mips16HardFloat) {
+    //
+    // currently we don't have symbols tagged with the mips16 or mips32
+    // qualifier so we will assume that we don't know what kind it is.
+    // and generate the helper
+    //
+    bool LookupHelper = true;
+    if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(CLI.Callee)) {
+      if (NoHelperNeeded.find(S->getSymbol()) != NoHelperNeeded.end()) {
+        LookupHelper = false;
+      }
+    }
+    if (LookupHelper) Mips16HelperFunction =
+      getMips16HelperFunction(CLI.RetTy, CLI.Args, NeedMips16Helper);
+
+  }
+
+  SDValue JumpTarget = Callee;
+
+  // T9 should contain the address of the callee function if
+  // -reloction-model=pic or it is an indirect call.
+  if (IsPICCall || !GlobalOrExternal) {
+    unsigned V0Reg = Mips::V0;
+    if (NeedMips16Helper) {
+      RegsToPass.push_front(std::make_pair(V0Reg, Callee));
+      JumpTarget = DAG.getExternalSymbol(Mips16HelperFunction, getPointerTy());
+      JumpTarget = getAddrGlobal(JumpTarget, DAG, MipsII::MO_GOT);
+    } else
+      RegsToPass.push_front(std::make_pair((unsigned)Mips::T9, Callee));
+  }
+
+  Ops.push_back(JumpTarget);
+
+  MipsTargetLowering::getOpndList(Ops, RegsToPass, IsPICCall, GlobalOrExternal,
+                                  InternalLinkage, CLI, Callee, Chain);
+}
+
+MachineBasicBlock *Mips16TargetLowering::
+emitSel16(unsigned Opc, MachineInstr *MI, MachineBasicBlock *BB) const {
+  if (DontExpandCondPseudos16)
+    return BB;
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+  DebugLoc DL = MI->getDebugLoc();
+  // To "insert" a SELECT_CC instruction, we actually have to insert the
+  // diamond control-flow pattern.  The incoming instruction knows the
+  // destination vreg to set, the condition code register to branch on, the
+  // true/false values to select between, and a branch opcode to use.
+  const BasicBlock *LLVM_BB = BB->getBasicBlock();
+  MachineFunction::iterator It = BB;
+  ++It;
+
+  //  thisMBB:
+  //  ...
+  //   TrueVal = ...
+  //   setcc r1, r2, r3
+  //   bNE   r1, r0, copy1MBB
+  //   fallthrough --> copy0MBB
+  MachineBasicBlock *thisMBB  = BB;
+  MachineFunction *F = BB->getParent();
+  MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
+  MachineBasicBlock *sinkMBB  = F->CreateMachineBasicBlock(LLVM_BB);
+  F->insert(It, copy0MBB);
+  F->insert(It, sinkMBB);
+
+  // Transfer the remainder of BB and its successor edges to sinkMBB.
+  sinkMBB->splice(sinkMBB->begin(), BB,
+                  llvm::next(MachineBasicBlock::iterator(MI)),
+                  BB->end());
+  sinkMBB->transferSuccessorsAndUpdatePHIs(BB);
+
+  // Next, add the true and fallthrough blocks as its successors.
+  BB->addSuccessor(copy0MBB);
+  BB->addSuccessor(sinkMBB);
+
+  BuildMI(BB, DL, TII->get(Opc)).addReg(MI->getOperand(3).getReg())
+    .addMBB(sinkMBB);
+
+  //  copy0MBB:
+  //   %FalseValue = ...
+  //   # fallthrough to sinkMBB
+  BB = copy0MBB;
+
+  // Update machine-CFG edges
+  BB->addSuccessor(sinkMBB);
+
+  //  sinkMBB:
+  //   %Result = phi [ %TrueValue, thisMBB ], [ %FalseValue, copy0MBB ]
+  //  ...
+  BB = sinkMBB;
+
+  BuildMI(*BB, BB->begin(), DL,
+          TII->get(Mips::PHI), MI->getOperand(0).getReg())
+    .addReg(MI->getOperand(1).getReg()).addMBB(thisMBB)
+    .addReg(MI->getOperand(2).getReg()).addMBB(copy0MBB);
+
+  MI->eraseFromParent();   // The pseudo instruction is gone now.
+  return BB;
+}
+
+MachineBasicBlock *Mips16TargetLowering::emitSelT16
+  (unsigned Opc1, unsigned Opc2,
+   MachineInstr *MI, MachineBasicBlock *BB) const {
+  if (DontExpandCondPseudos16)
+    return BB;
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+  DebugLoc DL = MI->getDebugLoc();
+  // To "insert" a SELECT_CC instruction, we actually have to insert the
+  // diamond control-flow pattern.  The incoming instruction knows the
+  // destination vreg to set, the condition code register to branch on, the
+  // true/false values to select between, and a branch opcode to use.
+  const BasicBlock *LLVM_BB = BB->getBasicBlock();
+  MachineFunction::iterator It = BB;
+  ++It;
+
+  //  thisMBB:
+  //  ...
+  //   TrueVal = ...
+  //   setcc r1, r2, r3
+  //   bNE   r1, r0, copy1MBB
+  //   fallthrough --> copy0MBB
+  MachineBasicBlock *thisMBB  = BB;
+  MachineFunction *F = BB->getParent();
+  MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
+  MachineBasicBlock *sinkMBB  = F->CreateMachineBasicBlock(LLVM_BB);
+  F->insert(It, copy0MBB);
+  F->insert(It, sinkMBB);
+
+  // Transfer the remainder of BB and its successor edges to sinkMBB.
+  sinkMBB->splice(sinkMBB->begin(), BB,
+                  llvm::next(MachineBasicBlock::iterator(MI)),
+                  BB->end());
+  sinkMBB->transferSuccessorsAndUpdatePHIs(BB);
+
+  // Next, add the true and fallthrough blocks as its successors.
+  BB->addSuccessor(copy0MBB);
+  BB->addSuccessor(sinkMBB);
+
+  BuildMI(BB, DL, TII->get(Opc2)).addReg(MI->getOperand(3).getReg())
+    .addReg(MI->getOperand(4).getReg());
+  BuildMI(BB, DL, TII->get(Opc1)).addMBB(sinkMBB);
+
+  //  copy0MBB:
+  //   %FalseValue = ...
+  //   # fallthrough to sinkMBB
+  BB = copy0MBB;
+
+  // Update machine-CFG edges
+  BB->addSuccessor(sinkMBB);
+
+  //  sinkMBB:
+  //   %Result = phi [ %TrueValue, thisMBB ], [ %FalseValue, copy0MBB ]
+  //  ...
+  BB = sinkMBB;
+
+  BuildMI(*BB, BB->begin(), DL,
+          TII->get(Mips::PHI), MI->getOperand(0).getReg())
+    .addReg(MI->getOperand(1).getReg()).addMBB(thisMBB)
+    .addReg(MI->getOperand(2).getReg()).addMBB(copy0MBB);
+
+  MI->eraseFromParent();   // The pseudo instruction is gone now.
+  return BB;
+
+}
+
+MachineBasicBlock *Mips16TargetLowering::emitSeliT16
+  (unsigned Opc1, unsigned Opc2,
+   MachineInstr *MI, MachineBasicBlock *BB) const {
+  if (DontExpandCondPseudos16)
+    return BB;
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+  DebugLoc DL = MI->getDebugLoc();
+  // To "insert" a SELECT_CC instruction, we actually have to insert the
+  // diamond control-flow pattern.  The incoming instruction knows the
+  // destination vreg to set, the condition code register to branch on, the
+  // true/false values to select between, and a branch opcode to use.
+  const BasicBlock *LLVM_BB = BB->getBasicBlock();
+  MachineFunction::iterator It = BB;
+  ++It;
+
+  //  thisMBB:
+  //  ...
+  //   TrueVal = ...
+  //   setcc r1, r2, r3
+  //   bNE   r1, r0, copy1MBB
+  //   fallthrough --> copy0MBB
+  MachineBasicBlock *thisMBB  = BB;
+  MachineFunction *F = BB->getParent();
+  MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
+  MachineBasicBlock *sinkMBB  = F->CreateMachineBasicBlock(LLVM_BB);
+  F->insert(It, copy0MBB);
+  F->insert(It, sinkMBB);
+
+  // Transfer the remainder of BB and its successor edges to sinkMBB.
+  sinkMBB->splice(sinkMBB->begin(), BB,
+                  llvm::next(MachineBasicBlock::iterator(MI)),
+                  BB->end());
+  sinkMBB->transferSuccessorsAndUpdatePHIs(BB);
+
+  // Next, add the true and fallthrough blocks as its successors.
+  BB->addSuccessor(copy0MBB);
+  BB->addSuccessor(sinkMBB);
+
+  BuildMI(BB, DL, TII->get(Opc2)).addReg(MI->getOperand(3).getReg())
+    .addImm(MI->getOperand(4).getImm());
+  BuildMI(BB, DL, TII->get(Opc1)).addMBB(sinkMBB);
+
+  //  copy0MBB:
+  //   %FalseValue = ...
+  //   # fallthrough to sinkMBB
+  BB = copy0MBB;
+
+  // Update machine-CFG edges
+  BB->addSuccessor(sinkMBB);
+
+  //  sinkMBB:
+  //   %Result = phi [ %TrueValue, thisMBB ], [ %FalseValue, copy0MBB ]
+  //  ...
+  BB = sinkMBB;
+
+  BuildMI(*BB, BB->begin(), DL,
+          TII->get(Mips::PHI), MI->getOperand(0).getReg())
+    .addReg(MI->getOperand(1).getReg()).addMBB(thisMBB)
+    .addReg(MI->getOperand(2).getReg()).addMBB(copy0MBB);
+
+  MI->eraseFromParent();   // The pseudo instruction is gone now.
+  return BB;
+
+}
+
+MachineBasicBlock
+  *Mips16TargetLowering::emitFEXT_T8I816_ins(unsigned BtOpc, unsigned CmpOpc,
+                                             MachineInstr *MI,
+                                             MachineBasicBlock *BB) const {
+  if (DontExpandCondPseudos16)
+    return BB;
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+  unsigned regX = MI->getOperand(0).getReg();
+  unsigned regY = MI->getOperand(1).getReg();
+  MachineBasicBlock *target = MI->getOperand(2).getMBB();
+  BuildMI(*BB, MI, MI->getDebugLoc(), TII->get(CmpOpc)).addReg(regX).addReg(regY);
+  BuildMI(*BB, MI, MI->getDebugLoc(), TII->get(BtOpc)).addMBB(target);
+  MI->eraseFromParent();   // The pseudo instruction is gone now.
+  return BB;
+}
+
+MachineBasicBlock *Mips16TargetLowering::emitFEXT_T8I8I16_ins(
+  unsigned BtOpc, unsigned CmpiOpc, unsigned CmpiXOpc,
+  MachineInstr *MI,  MachineBasicBlock *BB) const {
+  if (DontExpandCondPseudos16)
+    return BB;
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+  unsigned regX = MI->getOperand(0).getReg();
+  int64_t imm = MI->getOperand(1).getImm();
+  MachineBasicBlock *target = MI->getOperand(2).getMBB();
+  unsigned CmpOpc;
+  if (isUInt<8>(imm))
+    CmpOpc = CmpiOpc;
+  else if (isUInt<16>(imm))
+    CmpOpc = CmpiXOpc;
+  else
+    llvm_unreachable("immediate field not usable");
+  BuildMI(*BB, MI, MI->getDebugLoc(), TII->get(CmpOpc)).addReg(regX).addImm(imm);
+  BuildMI(*BB, MI, MI->getDebugLoc(), TII->get(BtOpc)).addMBB(target);
+  MI->eraseFromParent();   // The pseudo instruction is gone now.
+  return BB;
+}
+
+static unsigned Mips16WhichOp8uOr16simm
+  (unsigned shortOp, unsigned longOp, int64_t Imm) {
+  if (isUInt<8>(Imm))
+    return shortOp;
+  else if (isInt<16>(Imm))
+    return longOp;
+  else
+    llvm_unreachable("immediate field not usable");
+}
+
+MachineBasicBlock *Mips16TargetLowering::emitFEXT_CCRX16_ins(
+  unsigned SltOpc,
+  MachineInstr *MI,  MachineBasicBlock *BB) const {
+  if (DontExpandCondPseudos16)
+    return BB;
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+  unsigned CC = MI->getOperand(0).getReg();
+  unsigned regX = MI->getOperand(1).getReg();
+  unsigned regY = MI->getOperand(2).getReg();
+  BuildMI(*BB, MI, MI->getDebugLoc(),
+		  TII->get(SltOpc)).addReg(regX).addReg(regY);
+  BuildMI(*BB, MI, MI->getDebugLoc(),
+          TII->get(Mips::MoveR3216), CC).addReg(Mips::T8);
+  MI->eraseFromParent();   // The pseudo instruction is gone now.
+  return BB;
+}
+
+MachineBasicBlock *Mips16TargetLowering::emitFEXT_CCRXI16_ins(
+  unsigned SltiOpc, unsigned SltiXOpc,
+  MachineInstr *MI,  MachineBasicBlock *BB )const {
+  if (DontExpandCondPseudos16)
+    return BB;
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+  unsigned CC = MI->getOperand(0).getReg();
+  unsigned regX = MI->getOperand(1).getReg();
+  int64_t Imm = MI->getOperand(2).getImm();
+  unsigned SltOpc = Mips16WhichOp8uOr16simm(SltiOpc, SltiXOpc, Imm);
+  BuildMI(*BB, MI, MI->getDebugLoc(),
+          TII->get(SltOpc)).addReg(regX).addImm(Imm);
+  BuildMI(*BB, MI, MI->getDebugLoc(),
+          TII->get(Mips::MoveR3216), CC).addReg(Mips::T8);
+  MI->eraseFromParent();   // The pseudo instruction is gone now.
+  return BB;
+
+}
diff --git a/lib/Target/Mips/Mips16ISelLowering.h b/lib/Target/Mips/Mips16ISelLowering.h
new file mode 100644
index 0000000000..b23e2a1f37
--- /dev/null
+++ b/lib/Target/Mips/Mips16ISelLowering.h
@@ -0,0 +1,80 @@
+//===-- Mips16ISelLowering.h - Mips16 DAG Lowering Interface ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Subclass of MipsTargetLowering specialized for mips16.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef Mips16ISELLOWERING_H
+#define Mips16ISELLOWERING_H
+
+#include "MipsISelLowering.h"
+
+namespace llvm {
+  class Mips16TargetLowering : public MipsTargetLowering  {
+  public:
+    explicit Mips16TargetLowering(MipsTargetMachine &TM);
+
+    virtual bool allowsUnalignedMemoryAccesses(EVT VT, bool *Fast) const;
+
+    virtual MachineBasicBlock *
+    EmitInstrWithCustomInserter(MachineInstr *MI, MachineBasicBlock *MBB) const;
+
+  private:
+    virtual bool
+    isEligibleForTailCallOptimization(const MipsCC &MipsCCInfo,
+                                      unsigned NextStackOffset,
+                                      const MipsFunctionInfo& FI) const;
+
+    void setMips16LibcallName(RTLIB::Libcall, const char *Name);
+
+    void setMips16HardFloatLibCalls();
+
+    unsigned int
+      getMips16HelperFunctionStubNumber(ArgListTy &Args) const;
+
+    const char *getMips16HelperFunction
+      (Type* RetTy, ArgListTy &Args, bool &needHelper) const;
+
+    virtual void
+    getOpndList(SmallVectorImpl<SDValue> &Ops,
+                std::deque< std::pair<unsigned, SDValue> > &RegsToPass,
+                bool IsPICCall, bool GlobalOrExternal, bool InternalLinkage,
+                CallLoweringInfo &CLI, SDValue Callee, SDValue Chain) const;
+
+    MachineBasicBlock *emitSel16(unsigned Opc, MachineInstr *MI,
+                                 MachineBasicBlock *BB) const;
+
+    MachineBasicBlock *emitSeliT16(unsigned Opc1, unsigned Opc2,
+                                   MachineInstr *MI,
+                                   MachineBasicBlock *BB) const;
+
+    MachineBasicBlock *emitSelT16(unsigned Opc1, unsigned Opc2,
+                                  MachineInstr *MI,
+                                  MachineBasicBlock *BB) const;
+
+    MachineBasicBlock *emitFEXT_T8I816_ins(unsigned BtOpc, unsigned CmpOpc,
+                                           MachineInstr *MI,
+                                           MachineBasicBlock *BB) const;
+
+    MachineBasicBlock *emitFEXT_T8I8I16_ins(
+      unsigned BtOpc, unsigned CmpiOpc, unsigned CmpiXOpc,
+      MachineInstr *MI,  MachineBasicBlock *BB) const;
+
+    MachineBasicBlock *emitFEXT_CCRX16_ins(
+      unsigned SltOpc,
+      MachineInstr *MI,  MachineBasicBlock *BB) const;
+
+    MachineBasicBlock *emitFEXT_CCRXI16_ins(
+      unsigned SltiOpc, unsigned SltiXOpc,
+      MachineInstr *MI,  MachineBasicBlock *BB )const;
+  };
+}
+
+#endif // Mips16ISELLOWERING_H
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index c452dee8d0..4bf43f42e3 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -12,7 +12,6 @@
 //
 //===----------------------------------------------------------------------===//
 #define DEBUG_TYPE "mips-lower"
-#include <set>
 #include "MipsISelLowering.h"
 #include "InstPrinter/MipsInstPrinter.h"
 #include "MCTargetDesc/MipsBaseInfo.h"
@@ -42,26 +41,9 @@ using namespace llvm;
 STATISTIC(NumTailCalls, "Number of tail calls");
 
 static cl::opt<bool>
-EnableMipsTailCalls("enable-mips-tail-calls", cl::Hidden,
-                    cl::desc("MIPS: Enable tail calls."), cl::init(false));
-
-static cl::opt<bool>
 LargeGOT("mxgot", cl::Hidden,
          cl::desc("MIPS: Enable GOT larger than 64k."), cl::init(false));
 
-static cl::opt<bool>
-Mips16HardFloat("mips16-hard-float", cl::NotHidden,
-                cl::desc("MIPS: mips16 hard float enable."),
-                cl::init(false));
-
-static cl::opt<bool> DontExpandCondPseudos16(
-  "mips16-dont-expand-cond-pseudo",
-  cl::init(false),
-  cl::desc("Dont expand conditional move related "
-           "pseudos for Mips 16"),
-  cl::Hidden);
-
-
 static const uint16_t O32IntRegs[4] = {
   Mips::A0, Mips::A1, Mips::A2, Mips::A3
 };
@@ -88,7 +70,7 @@ static bool isShiftedMask(uint64_t I, uint64_t &Pos, uint64_t &Size) {
   return true;
 }
 
-static SDValue getGlobalReg(SelectionDAG &DAG, EVT Ty) {
+SDValue MipsTargetLowering::getGlobalReg(SelectionDAG &DAG, EVT Ty) const {
   MipsFunctionInfo *FI = DAG.getMachineFunction().getInfo<MipsFunctionInfo>();
   return DAG.getRegister(FI->getGlobalBaseReg(), Ty);
 }
@@ -123,7 +105,8 @@ static SDValue getAddrNonPIC(SDValue Op, SelectionDAG &DAG) {
                      DAG.getNode(MipsISD::Lo, DL, Ty, Lo));
 }
 
-static SDValue getAddrLocal(SDValue Op, SelectionDAG &DAG, bool HasMips64) {
+SDValue MipsTargetLowering::getAddrLocal(SDValue Op, SelectionDAG &DAG,
+                                         bool HasMips64) const {
   DebugLoc DL = Op.getDebugLoc();
   EVT Ty = Op.getValueType();
   unsigned GOTFlag = HasMips64 ? MipsII::MO_GOT_PAGE : MipsII::MO_GOT;
@@ -137,7 +120,8 @@ static SDValue getAddrLocal(SDValue Op, SelectionDAG &DAG, bool HasMips64) {
   return DAG.getNode(ISD::ADD, DL, Ty, Load, Lo);
 }
 
-static SDValue getAddrGlobal(SDValue Op, SelectionDAG &DAG, unsigned Flag) {
+SDValue MipsTargetLowering::getAddrGlobal(SDValue Op, SelectionDAG &DAG,
+                                          unsigned Flag) const {
   DebugLoc DL = Op.getDebugLoc();
   EVT Ty = Op.getValueType();
   SDValue Tgt = DAG.getNode(MipsISD::Wrapper, DL, Ty, getGlobalReg(DAG, Ty),
@@ -146,8 +130,9 @@ static SDValue getAddrGlobal(SDValue Op, SelectionDAG &DAG, unsigned Flag) {
                      MachinePointerInfo::getGOT(), false, false, false, 0);
 }
 
-static SDValue getAddrGlobalLargeGOT(SDValue Op, SelectionDAG &DAG,
-                                     unsigned HiFlag, unsigned LoFlag) {
+SDValue MipsTargetLowering::getAddrGlobalLargeGOT(SDValue Op, SelectionDAG &DAG,
+                                                  unsigned HiFlag,
+                                                  unsigned LoFlag) const {
   DebugLoc DL = Op.getDebugLoc();
   EVT Ty = Op.getValueType();
   SDValue Hi = DAG.getNode(MipsISD::Hi, DL, Ty, getTargetNode(Op, DAG, HiFlag));
@@ -211,110 +196,17 @@ const char *MipsTargetLowering::getTargetNodeName(unsigned Opcode) const {
   }
 }
 
-namespace {
-  struct LTStr {
-    bool operator()(const char *S1, const char *S2) const
-    {
-      return strcmp(S1, S2) < 0;
-    }
-  };
-
-  std::set<const char*, LTStr> NoHelperNeeded;
-}
-
-void MipsTargetLowering::setMips16LibcallName
-  (RTLIB::Libcall L, const char *Name) {
-  setLibcallName(L, Name);
-  NoHelperNeeded.insert(Name);
-}
-
-void MipsTargetLowering::setMips16HardFloatLibCalls() {
-  setMips16LibcallName(RTLIB::ADD_F32, "__mips16_addsf3");
-  setMips16LibcallName(RTLIB::ADD_F64, "__mips16_adddf3");