[llvm] r187399 - [PowerPC] Skeletal FastISel support for 64-bit PowerPC ELF.

Hal Finkel hfinkel at anl.gov
Mon Jul 29 19:09:09 PDT 2013


----- Original Message -----
> Author: wschmidt
> Date: Mon Jul 29 19:50:39 2013
> New Revision: 187399
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=187399&view=rev
> Log:
> [PowerPC] Skeletal FastISel support for 64-bit PowerPC ELF.
> 
> This is the first of many upcoming patches for PowerPC fast
> instruction selection support.  This patch implements the minimum
> necessary for a functional (but extremely limited) FastISel pass.  It
> allows the table-generated portions of the selector to be created and
> used, but in most cases selection will fall back to the DAG selector.
> None of the block terminator instructions are implemented yet, and
> most interesting instructions require some special handling.
> Therefore there aren't any new test cases with this patch.  There
> will
> be quite a few tests coming with future patches.
> 
> This patch adds the make/CMake support for the new code (including
> tablegen -gen-fast-isel) and creates the FastISel object for PPC64
> ELF
> only.  It instantiates the necessary virtual functions
> (TargetSelectInstruction, TargetMaterializeConstant,
> TargetMaterializeAlloca, tryToFoldLoadIntoMI, and
> FastLowerArguments),
> but of these, only TargetMaterializeConstant contains any useful
> implementation.  This is present since the table-generated code
> requires the ability to materialize integer constants for some
> instructions.
> 
> This patch has been tested by building and running the
> projects/test-suite code with -O0.  All tests passed with the
> exception of a couple of long-running tests that time out using -O0
> code generation.

Can you please increase the timeout and make sure these pass?

Thanks again,
Hal

> 
> Added:
>     llvm/trunk/lib/Target/PowerPC/PPCFastISel.cpp
> Modified:
>     llvm/trunk/lib/Target/PowerPC/CMakeLists.txt
>     llvm/trunk/lib/Target/PowerPC/Makefile
>     llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp
>     llvm/trunk/lib/Target/PowerPC/PPCISelLowering.h
> 
> Modified: llvm/trunk/lib/Target/PowerPC/CMakeLists.txt
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/CMakeLists.txt?rev=187399&r1=187398&r2=187399&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/PowerPC/CMakeLists.txt (original)
> +++ llvm/trunk/lib/Target/PowerPC/CMakeLists.txt Mon Jul 29 19:50:39
> 2013
> @@ -7,6 +7,7 @@ tablegen(LLVM PPCGenMCCodeEmitter.inc -g
>  tablegen(LLVM PPCGenRegisterInfo.inc -gen-register-info)
>  tablegen(LLVM PPCGenInstrInfo.inc -gen-instr-info)
>  tablegen(LLVM PPCGenDAGISel.inc -gen-dag-isel)
> +tablegen(LLVM PPCGenFastISel.inc -gen-fast-isel)
>  tablegen(LLVM PPCGenCallingConv.inc -gen-callingconv)
>  tablegen(LLVM PPCGenSubtargetInfo.inc -gen-subtarget)
>  add_public_tablegen_target(PowerPCCommonTableGen)
> @@ -20,6 +21,7 @@ add_llvm_target(PowerPCCodeGen
>    PPCInstrInfo.cpp
>    PPCISelDAGToDAG.cpp
>    PPCISelLowering.cpp
> +  PPCFastISel.cpp
>    PPCFrameLowering.cpp
>    PPCJITInfo.cpp
>    PPCMCInstLower.cpp
> 
> Modified: llvm/trunk/lib/Target/PowerPC/Makefile
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/Makefile?rev=187399&r1=187398&r2=187399&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/PowerPC/Makefile (original)
> +++ llvm/trunk/lib/Target/PowerPC/Makefile Mon Jul 29 19:50:39 2013
> @@ -16,7 +16,7 @@ BUILT_SOURCES = PPCGenRegisterInfo.inc P
>                  PPCGenAsmWriter.inc  PPCGenCodeEmitter.inc \
>                  PPCGenInstrInfo.inc PPCGenDAGISel.inc \
>                  PPCGenSubtargetInfo.inc PPCGenCallingConv.inc \
> -                PPCGenMCCodeEmitter.inc
> +                PPCGenMCCodeEmitter.inc PPCGenFastISel.inc
>  
>  DIRS = AsmParser InstPrinter TargetInfo MCTargetDesc
>  
> 
> Added: llvm/trunk/lib/Target/PowerPC/PPCFastISel.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCFastISel.cpp?rev=187399&view=auto
> ==============================================================================
> --- llvm/trunk/lib/Target/PowerPC/PPCFastISel.cpp (added)
> +++ llvm/trunk/lib/Target/PowerPC/PPCFastISel.cpp Mon Jul 29 19:50:39
> 2013
> @@ -0,0 +1,328 @@
> +//===-- PPCFastISel.cpp - PowerPC FastISel implementation
> -----------------===//
> +//
> +//                     The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open
> Source
> +// License. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +//
> +// This file defines the PowerPC-specific support for the FastISel
> class. Some
> +// of the target-specific code is generated by tablegen in the file
> +// PPCGenFastISel.inc, which is #included here.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +#define DEBUG_TYPE "ppcfastisel"
> +#include "PPC.h"
> +#include "PPCISelLowering.h"
> +#include "PPCSubtarget.h"
> +#include "PPCTargetMachine.h"
> +#include "MCTargetDesc/PPCPredicates.h"
> +#include "llvm/ADT/Optional.h"
> +#include "llvm/CodeGen/CallingConvLower.h"
> +#include "llvm/CodeGen/FastISel.h"
> +#include "llvm/CodeGen/FunctionLoweringInfo.h"
> +#include "llvm/CodeGen/MachineConstantPool.h"
> +#include "llvm/CodeGen/MachineFrameInfo.h"
> +#include "llvm/CodeGen/MachineInstrBuilder.h"
> +#include "llvm/CodeGen/MachineRegisterInfo.h"
> +#include "llvm/IR/CallingConv.h"
> +#include "llvm/IR/GlobalAlias.h"
> +#include "llvm/IR/GlobalVariable.h"
> +#include "llvm/IR/IntrinsicInst.h"
> +#include "llvm/IR/Operator.h"
> +#include "llvm/Support/Debug.h"
> +#include "llvm/Support/GetElementPtrTypeIterator.h"
> +#include "llvm/Target/TargetLowering.h"
> +#include "llvm/Target/TargetMachine.h"
> +
> +using namespace llvm;
> +
> +namespace {
> +
> +typedef struct Address {
> +  enum {
> +    RegBase,
> +    FrameIndexBase
> +  } BaseType;
> +
> +  union {
> +    unsigned Reg;
> +    int FI;
> +  } Base;
> +
> +  int Offset;
> +
> +  // Innocuous defaults for our address.
> +  Address()
> +   : BaseType(RegBase), Offset(0) {
> +     Base.Reg = 0;
> +   }
> +} Address;
> +
> +class PPCFastISel : public FastISel {
> +
> +  const TargetMachine &TM;
> +  const TargetInstrInfo &TII;
> +  const TargetLowering &TLI;
> +  const PPCSubtarget &PPCSubTarget;
> +  LLVMContext *Context;
> +
> +  public:
> +    explicit PPCFastISel(FunctionLoweringInfo &FuncInfo,
> +                         const TargetLibraryInfo *LibInfo)
> +    : FastISel(FuncInfo, LibInfo),
> +      TM(FuncInfo.MF->getTarget()),
> +      TII(*TM.getInstrInfo()),
> +      TLI(*TM.getTargetLowering()),
> +      PPCSubTarget(
> +       *((static_cast<const PPCTargetMachine
> *>(&TM))->getSubtargetImpl())
> +      ),
> +      Context(&FuncInfo.Fn->getContext()) { }
> +
> +  // Backend specific FastISel code.
> +  private:
> +    virtual bool TargetSelectInstruction(const Instruction *I);
> +    virtual unsigned TargetMaterializeConstant(const Constant *C);
> +    virtual unsigned TargetMaterializeAlloca(const AllocaInst *AI);
> +    virtual bool tryToFoldLoadIntoMI(MachineInstr *MI, unsigned
> OpNo,
> +                                     const LoadInst *LI);
> +    virtual bool FastLowerArguments();
> +
> +  // Utility routines.
> +  private:
> +    unsigned PPCMaterializeFP(const ConstantFP *CFP, MVT VT);
> +    unsigned PPCMaterializeInt(const Constant *C, MVT VT);
> +    unsigned PPCMaterialize32BitInt(int64_t Imm,
> +                                    const TargetRegisterClass *RC);
> +    unsigned PPCMaterialize64BitInt(int64_t Imm,
> +                                    const TargetRegisterClass *RC);
> +
> +  private:
> +  #include "PPCGenFastISel.inc"
> +
> +};
> +
> +} // end anonymous namespace
> +
> +// Attempt to fast-select an instruction that wasn't handled by
> +// the table-generated machinery.  TBD.
> +bool PPCFastISel::TargetSelectInstruction(const Instruction *I) {
> +  return I && false;
> +}
> +
> +// Materialize a floating-point constant into a register, and return
> +// the register number (or zero if we failed to handle it).
> +unsigned PPCFastISel::PPCMaterializeFP(const ConstantFP *CFP, MVT
> VT) {
> +  // No plans to handle long double here.
> +  if (VT != MVT::f32 && VT != MVT::f64)
> +    return 0;
> +
> +  // All FP constants are loaded from the constant pool.
> +  unsigned Align = TD.getPrefTypeAlignment(CFP->getType());
> +  assert(Align > 0 && "Unexpectedly missing alignment
> information!");
> +  unsigned Idx = MCP.getConstantPoolIndex(cast<Constant>(CFP),
> Align);
> +  unsigned DestReg = createResultReg(TLI.getRegClassFor(VT));
> +  CodeModel::Model CModel = TM.getCodeModel();
> +
> +  MachineMemOperand *MMO =
> +    FuncInfo.MF->getMachineMemOperand(
> +      MachinePointerInfo::getConstantPool(),
> MachineMemOperand::MOLoad,
> +      (VT == MVT::f32) ? 4 : 8, Align);
> +
> +  // For small code model, generate a LDtocCPT.
> +  if (CModel == CodeModel::Small || CModel == CodeModel::JITDefault)
> +    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
> TII.get(PPC::LDtocCPT),
> +            DestReg)
> +      .addConstantPoolIndex(Idx).addReg(PPC::X2).addMemOperand(MMO);
> +  else {
> +    // Otherwise we generate LF[SD](Idx[lo], ADDIStocHA(X2, Idx)).
> +    unsigned Opc = (VT == MVT::f32) ? PPC::LFS : PPC::LFD;
> +    unsigned TmpReg =
> createResultReg(&PPC::G8RC_and_G8RC_NOX0RegClass);
> +    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
> TII.get(PPC::ADDIStocHA),
> +            TmpReg).addReg(PPC::X2).addConstantPoolIndex(Idx);
> +    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(Opc),
> DestReg)
> +      .addConstantPoolIndex(Idx, 0, PPCII::MO_TOC_LO)
> +      .addReg(TmpReg)
> +      .addMemOperand(MMO);
> +  }
> +
> +  return DestReg;
> +}
> +
> +// Materialize a 32-bit integer constant into a register, and return
> +// the register number (or zero if we failed to handle it).
> +unsigned PPCFastISel::PPCMaterialize32BitInt(int64_t Imm,
> +                                             const
> TargetRegisterClass *RC) {
> +  unsigned Lo = Imm & 0xFFFF;
> +  unsigned Hi = (Imm >> 16) & 0xFFFF;
> +
> +  unsigned ResultReg = createResultReg(RC);
> +  bool IsGPRC = RC->hasSuperClassEq(&PPC::GPRCRegClass);
> +
> +  if (isInt<16>(Imm))
> +    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
> +            TII.get(IsGPRC ? PPC::LI : PPC::LI8), ResultReg)
> +      .addImm(Imm);
> +  else if (Lo) {
> +    // Both Lo and Hi have nonzero bits.
> +    unsigned TmpReg = createResultReg(RC);
> +    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
> +            TII.get(IsGPRC ? PPC::LIS : PPC::LIS8), TmpReg)
> +      .addImm(Hi);
> +    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
> +            TII.get(IsGPRC ? PPC::ORI : PPC::ORI8), ResultReg)
> +      .addReg(TmpReg).addImm(Lo);
> +  } else
> +    // Just Hi bits.
> +    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
> +            TII.get(IsGPRC ? PPC::LIS : PPC::LIS8), ResultReg)
> +      .addImm(Hi);
> +
> +  return ResultReg;
> +}
> +
> +// Materialize a 64-bit integer constant into a register, and return
> +// the register number (or zero if we failed to handle it).
> +unsigned PPCFastISel::PPCMaterialize64BitInt(int64_t Imm,
> +                                             const
> TargetRegisterClass *RC) {
> +  unsigned Remainder = 0;
> +  unsigned Shift = 0;
> +
> +  // If the value doesn't fit in 32 bits, see if we can shift it
> +  // so that it fits in 32 bits.
> +  if (!isInt<32>(Imm)) {
> +    Shift = countTrailingZeros<uint64_t>(Imm);
> +    int64_t ImmSh = static_cast<uint64_t>(Imm) >> Shift;
> +
> +    if (isInt<32>(ImmSh))
> +      Imm = ImmSh;
> +    else {
> +      Remainder = Imm;
> +      Shift = 32;
> +      Imm >>= 32;
> +    }
> +  }
> +
> +  // Handle the high-order 32 bits (if shifted) or the whole 32 bits
> +  // (if not shifted).
> +  unsigned TmpReg1 = PPCMaterialize32BitInt(Imm, RC);
> +  if (!Shift)
> +    return TmpReg1;
> +
> +  // If upper 32 bits were not zero, we've built them and need to
> shift
> +  // them into place.
> +  unsigned TmpReg2;
> +  if (Imm) {
> +    TmpReg2 = createResultReg(RC);
> +    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
> TII.get(PPC::RLDICR),
> +            TmpReg2).addReg(TmpReg1).addImm(Shift).addImm(63 -
> Shift);
> +  } else
> +    TmpReg2 = TmpReg1;
> +
> +  unsigned TmpReg3, Hi, Lo;
> +  if ((Hi = (Remainder >> 16) & 0xFFFF)) {
> +    TmpReg3 = createResultReg(RC);
> +    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
> TII.get(PPC::ORIS8),
> +            TmpReg3).addReg(TmpReg2).addImm(Hi);
> +  } else
> +    TmpReg3 = TmpReg2;
> +
> +  if ((Lo = Remainder & 0xFFFF)) {
> +    unsigned ResultReg = createResultReg(RC);
> +    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
> TII.get(PPC::ORI8),
> +            ResultReg).addReg(TmpReg3).addImm(Lo);
> +    return ResultReg;
> +  }
> +
> +  return TmpReg3;
> +}
> +
> +
> +// Materialize an integer constant into a register, and return
> +// the register number (or zero if we failed to handle it).
> +unsigned PPCFastISel::PPCMaterializeInt(const Constant *C, MVT VT) {
> +
> +  if (VT != MVT::i64 && VT != MVT::i32 && VT != MVT::i16 &&
> +      VT != MVT::i8 && VT != MVT::i1)
> +    return 0;
> +
> +  const TargetRegisterClass *RC = ((VT == MVT::i64) ?
> &PPC::G8RCRegClass :
> +                                   &PPC::GPRCRegClass);
> +
> +  // If the constant is in range, use a load-immediate.
> +  const ConstantInt *CI = cast<ConstantInt>(C);
> +  if (isInt<16>(CI->getSExtValue())) {
> +    unsigned Opc = (VT == MVT::i64) ? PPC::LI8 : PPC::LI;
> +    unsigned ImmReg = createResultReg(RC);
> +    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(Opc),
> ImmReg)
> +      .addImm(CI->getSExtValue());
> +    return ImmReg;
> +  }
> +
> +  // Construct the constant piecewise.
> +  int64_t Imm = CI->getZExtValue();
> +
> +  if (VT == MVT::i64)
> +    return PPCMaterialize64BitInt(Imm, RC);
> +  else if (VT == MVT::i32)
> +    return PPCMaterialize32BitInt(Imm, RC);
> +
> +  return 0;
> +}
> +
> +// Materialize a constant into a register, and return the register
> +// number (or zero if we failed to handle it).
> +unsigned PPCFastISel::TargetMaterializeConstant(const Constant *C) {
> +  EVT CEVT = TLI.getValueType(C->getType(), true);
> +
> +  // Only handle simple types.
> +  if (!CEVT.isSimple()) return 0;
> +  MVT VT = CEVT.getSimpleVT();
> +
> +  if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C))
> +    return PPCMaterializeFP(CFP, VT);
> +  else if (isa<ConstantInt>(C))
> +    return PPCMaterializeInt(C, VT);
> +  // TBD: Global values.
> +
> +  return 0;
> +}
> +
> +// Materialize the address created by an alloca into a register, and
> +// return the register number (or zero if we failed to handle it).
>  TBD.
> +unsigned PPCFastISel::TargetMaterializeAlloca(const AllocaInst *AI)
> {
> +  return AI && 0;
> +}
> +
> +// Fold loads into extends when possible.  TBD.
> +bool PPCFastISel::tryToFoldLoadIntoMI(MachineInstr *MI, unsigned
> OpNo,
> +                                      const LoadInst *LI) {
> +  return MI && OpNo && LI && false;
> +}
> +
> +// Attempt to lower call arguments in a faster way than done by
> +// the selection DAG code.
> +bool PPCFastISel::FastLowerArguments() {
> +  // Defer to normal argument lowering for now.  It's reasonably
> +  // efficient.  Consider doing something like ARM to handle the
> +  // case where all args fit in registers, no varargs, no float
> +  // or vector args.
> +  return false;
> +}
> +
> +namespace llvm {
> +  // Create the fast instruction selector for PowerPC64 ELF.
> +  FastISel *PPC::createFastISel(FunctionLoweringInfo &FuncInfo,
> +                                const TargetLibraryInfo *LibInfo) {
> +    const TargetMachine &TM = FuncInfo.MF->getTarget();
> +
> +    // Only available on 64-bit ELF for now.
> +    const PPCSubtarget *Subtarget =
> &TM.getSubtarget<PPCSubtarget>();
> +    if (Subtarget->isPPC64() && Subtarget->isSVR4ABI())
> +      return new PPCFastISel(FuncInfo, LibInfo);
> +
> +    return 0;
> +  }
> +}
> 
> Modified: llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp?rev=187399&r1=187398&r2=187399&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp (original)
> +++ llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp Mon Jul 29
> 19:50:39 2013
> @@ -7885,3 +7885,9 @@ Sched::Preference PPCTargetLowering::get
>    return Sched::ILP;
>  }
>  
> +// Create a fast isel object.
> +FastISel *
> +PPCTargetLowering::createFastISel(FunctionLoweringInfo &FuncInfo,
> +                                  const TargetLibraryInfo *LibInfo)
> const {
> +  return PPC::createFastISel(FuncInfo, LibInfo);
> +}
> 
> Modified: llvm/trunk/lib/Target/PowerPC/PPCISelLowering.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCISelLowering.h?rev=187399&r1=187398&r2=187399&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/PowerPC/PPCISelLowering.h (original)
> +++ llvm/trunk/lib/Target/PowerPC/PPCISelLowering.h Mon Jul 29
> 19:50:39 2013
> @@ -465,6 +465,11 @@ namespace llvm {
>      /// expanded to fmul + fadd.
>      virtual bool isFMAFasterThanFMulAndFAdd(EVT VT) const;
>  
> +    /// createFastISel - This method returns a target-specific
> FastISel object,
> +    /// or null if the target does not support "fast" instruction
> selection.
> +    virtual FastISel *createFastISel(FunctionLoweringInfo &FuncInfo,
> +                                     const TargetLibraryInfo
> *LibInfo) const;
> +
>    private:
>      SDValue getFramePointerFrameIndex(SelectionDAG & DAG) const;
>      SDValue getReturnAddrFrameIndex(SelectionDAG & DAG) const;
> @@ -624,6 +629,11 @@ namespace llvm {
>      SDValue DAGCombineFastRecipFSQRT(SDValue Op, DAGCombinerInfo
>      &DCI) const;
>    };
>  
> +  namespace PPC {
> +    FastISel *createFastISel(FunctionLoweringInfo &FuncInfo,
> +                             const TargetLibraryInfo *LibInfo);
> +  }
> +
>    bool CC_PPC32_SVR4_Custom_Dummy(unsigned &ValNo, MVT &ValVT, MVT
>    &LocVT,
>                                    CCValAssign::LocInfo &LocInfo,
>                                    ISD::ArgFlagsTy &ArgFlags,
> 
> 
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> llvm-commits at cs.uiuc.edu
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> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory



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