Initial commit for Mips Fast ISel

[rkotler]

Summary

Shell for adding Mips Fast ISel.

[dsanders]

LGTM

[dsanders]

Reed committed this in rL206505

lib/Target/Mips/CMakeLists.txt

add_llvm_target(MipsCodeGen
   Mips16ISelDAGToDAG.cpp
   Mips16ISelLowering.cpp
   Mips16RegisterInfo.cpp
   MipsAnalyzeImmediate.cpp
   MipsAsmPrinter.cpp
   MipsCodeEmitter.cpp
   MipsConstantIslandPass.cpp
   MipsDelaySlotFiller.cpp
+  MipsFastISel.cpp
   MipsJITInfo.cpp
   MipsInstrInfo.cpp
   MipsISelDAGToDAG.cpp
   MipsISelLowering.cpp
   MipsFrameLowering.cpp
   MipsLongBranch.cpp
   MipsMCInstLower.cpp
   MipsMachineFunction.cpp

lib/Target/Mips/MipsFastISel.cpp

+//===-- MipsastISel.cpp - Mips FastISel implementation
+//---------------------===//
+
+#include "llvm/CodeGen/FunctionLoweringInfo.h"
+#include "llvm/CodeGen/FastISel.h"
+#include "llvm/Target/TargetLibraryInfo.h"
+#include "MipsISelLowering.h"
+
+using namespace llvm;
+
+namespace {
+
+class MipsFastISel final : public FastISel {
+
+public:
+  explicit MipsFastISel(FunctionLoweringInfo &funcInfo,
+                        const TargetLibraryInfo *libInfo)
+      : FastISel(funcInfo, libInfo) {}
+  bool TargetSelectInstruction(const Instruction *I) override { return false; }
+};
+}
+
+namespace llvm {
+FastISel *Mips::createFastISel(FunctionLoweringInfo &funcInfo,
+                               const TargetLibraryInfo *libInfo) {
+  return new MipsFastISel(funcInfo, libInfo);
+}
+}

lib/Target/Mips/MipsISelLowering.h

namespace llvm {
 
   class MipsTargetLowering : public TargetLowering  {
     bool isMicroMips;
   public:
     explicit MipsTargetLowering(MipsTargetMachine &TM);
 
     static const MipsTargetLowering *create(MipsTargetMachine &TM);
 
+    /// createFastISel - This method returns a target specific FastISel object,
+    /// or null if the target does not support "fast" ISel.
+    FastISel *createFastISel(FunctionLoweringInfo &funcInfo,
+                             const TargetLibraryInfo *libInfo) const override;
+
     virtual MVT getScalarShiftAmountTy(EVT LHSTy) const { return MVT::i32; }
 
     virtual void LowerOperationWrapper(SDNode *N,
                                        SmallVectorImpl<SDValue> &Results,
                                        SelectionDAG &DAG) const;
 
     /// LowerOperation - Provide custom lowering hooks for some operations.
     virtual SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const;
MachineBasicBlock *emitAtomicCmpSwap(MachineInstr *MI,
                                   MachineBasicBlock *BB, unsigned Size) const;
     MachineBasicBlock *emitAtomicCmpSwapPartword(MachineInstr *MI,
                                   MachineBasicBlock *BB, unsigned Size) const;
   };
 
   /// Create MipsTargetLowering objects.
   const MipsTargetLowering *createMips16TargetLowering(MipsTargetMachine &TM);
   const MipsTargetLowering *createMipsSETargetLowering(MipsTargetMachine &TM);
+
+  namespace Mips {
+    FastISel *createFastISel(FunctionLoweringInfo &funcInfo,
+                             const TargetLibraryInfo *libInfo);
+  }
 }
 
 #endif // MipsISELLOWERING_H

lib/Target/Mips/MipsISelLowering.cpp

 LargeGOT("mxgot", cl::Hidden,
          cl::desc("MIPS: Enable GOT larger than 64k."), cl::init(false));
 
 static cl::opt<bool>
 NoZeroDivCheck("mno-check-zero-division", cl::Hidden,
                cl::desc("MIPS: Don't trap on integer division by zero."),
                cl::init(false));
 
+cl::opt<bool>
+EnableMipsFastISel("mips-fast-isel", cl::Hidden,
+  cl::desc("Allow mips-fast-isel to be used"),
+  cl::init(false));
+
 static const MCPhysReg O32IntRegs[4] = {
   Mips::A0, Mips::A1, Mips::A2, Mips::A3
 };
 
 static const MCPhysReg Mips64IntRegs[8] = {
   Mips::A0_64, Mips::A1_64, Mips::A2_64, Mips::A3_64,
   Mips::T0_64, Mips::T1_64, Mips::T2_64, Mips::T3_64
 };

 
 const MipsTargetLowering *MipsTargetLowering::create(MipsTargetMachine &TM) {
   if (TM.getSubtargetImpl()->inMips16Mode())
     return llvm::createMips16TargetLowering(TM);
 
   return llvm::createMipsSETargetLowering(TM);
 }
 
+// Create a fast isel object.
+FastISel *
+MipsTargetLowering::createFastISel(FunctionLoweringInfo &funcInfo,
+                                  const TargetLibraryInfo *libInfo) const {
+  if (!EnableMipsFastISel)
+    return TargetLowering::createFastISel(funcInfo, libInfo);
+  return Mips::createFastISel(funcInfo, libInfo);
+}
+
 EVT MipsTargetLowering::getSetCCResultType(LLVMContext &, EVT VT) const {
   if (!VT.isVector())
     return MVT::i32;
   return VT.changeVectorElementTypeToInteger();
 }
 
 static SDValue performDivRemCombine(SDNode *N, SelectionDAG &DAG,
                                     TargetLowering::DAGCombinerInfo &DCI,