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llvm-6502/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
Evan Cheng 7564e0b46d Complex pattern isel code shouldn't select nodes. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26010 91177308-0d34-0410-b5e6-96231b3b80d8
2006-02-05 08:45:01 +00:00

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//===-- PPCISelDAGToDAG.cpp - PPC --pattern matching inst selector --------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a pattern matching instruction selector for PowerPC,
// converting from a legalized dag to a PPC dag.
//
//===----------------------------------------------------------------------===//
#include "PPC.h"
#include "PPCTargetMachine.h"
#include "PPCISelLowering.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/SSARegMap.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Constants.h"
#include "llvm/GlobalValue.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
#include <iostream>
#include <set>
using namespace llvm;
namespace {
Statistic<> FrameOff("ppc-codegen", "Number of frame idx offsets collapsed");
//===--------------------------------------------------------------------===//
/// PPCDAGToDAGISel - PPC specific code to select PPC machine
/// instructions for SelectionDAG operations.
///
class PPCDAGToDAGISel : public SelectionDAGISel {
PPCTargetLowering PPCLowering;
unsigned GlobalBaseReg;
public:
PPCDAGToDAGISel(TargetMachine &TM)
: SelectionDAGISel(PPCLowering), PPCLowering(TM) {}
virtual bool runOnFunction(Function &Fn) {
// Make sure we re-emit a set of the global base reg if necessary
GlobalBaseReg = 0;
return SelectionDAGISel::runOnFunction(Fn);
}
/// getI32Imm - Return a target constant with the specified value, of type
/// i32.
inline SDOperand getI32Imm(unsigned Imm) {
return CurDAG->getTargetConstant(Imm, MVT::i32);
}
/// getGlobalBaseReg - insert code into the entry mbb to materialize the PIC
/// base register. Return the virtual register that holds this value.
SDOperand getGlobalBaseReg();
// Select - Convert the specified operand from a target-independent to a
// target-specific node if it hasn't already been changed.
SDOperand Select(SDOperand Op);
SDNode *SelectBitfieldInsert(SDNode *N);
/// SelectCC - Select a comparison of the specified values with the
/// specified condition code, returning the CR# of the expression.
SDOperand SelectCC(SDOperand LHS, SDOperand RHS, ISD::CondCode CC);
/// SelectAddrImm - Returns true if the address N can be represented by
/// a base register plus a signed 16-bit displacement [r+imm].
bool SelectAddrImm(SDOperand N, SDOperand &Disp, SDOperand &Base);
/// SelectAddrIdx - Given the specified addressed, check to see if it can be
/// represented as an indexed [r+r] operation. Returns false if it can
/// be represented by [r+imm], which are preferred.
bool SelectAddrIdx(SDOperand N, SDOperand &Base, SDOperand &Index);
/// SelectAddrIdxOnly - Given the specified addressed, force it to be
/// represented as an indexed [r+r] operation.
bool SelectAddrIdxOnly(SDOperand N, SDOperand &Base, SDOperand &Index);
SDOperand BuildSDIVSequence(SDNode *N);
SDOperand BuildUDIVSequence(SDNode *N);
/// InstructionSelectBasicBlock - This callback is invoked by
/// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
virtual void InstructionSelectBasicBlock(SelectionDAG &DAG);
virtual const char *getPassName() const {
return "PowerPC DAG->DAG Pattern Instruction Selection";
}
// Include the pieces autogenerated from the target description.
#include "PPCGenDAGISel.inc"
private:
SDOperand SelectADD_PARTS(SDOperand Op);
SDOperand SelectSUB_PARTS(SDOperand Op);
SDOperand SelectSETCC(SDOperand Op);
SDOperand SelectCALL(SDOperand Op);
};
}
/// InstructionSelectBasicBlock - This callback is invoked by
/// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
void PPCDAGToDAGISel::InstructionSelectBasicBlock(SelectionDAG &DAG) {
DEBUG(BB->dump());
// The selection process is inherently a bottom-up recursive process (users
// select their uses before themselves). Given infinite stack space, we
// could just start selecting on the root and traverse the whole graph. In
// practice however, this causes us to run out of stack space on large basic
// blocks. To avoid this problem, select the entry node, then all its uses,
// iteratively instead of recursively.
std::vector<SDOperand> Worklist;
Worklist.push_back(DAG.getEntryNode());
// Note that we can do this in the PPC target (scanning forward across token
// chain edges) because no nodes ever get folded across these edges. On a
// target like X86 which supports load/modify/store operations, this would
// have to be more careful.
while (!Worklist.empty()) {
SDOperand Node = Worklist.back();
Worklist.pop_back();
// Chose from the least deep of the top two nodes.
if (!Worklist.empty() &&
Worklist.back().Val->getNodeDepth() < Node.Val->getNodeDepth())
std::swap(Worklist.back(), Node);
if ((Node.Val->getOpcode() >= ISD::BUILTIN_OP_END &&
Node.Val->getOpcode() < PPCISD::FIRST_NUMBER) ||
CodeGenMap.count(Node)) continue;
for (SDNode::use_iterator UI = Node.Val->use_begin(),
E = Node.Val->use_end(); UI != E; ++UI) {
// Scan the values. If this use has a value that is a token chain, add it
// to the worklist.
SDNode *User = *UI;
for (unsigned i = 0, e = User->getNumValues(); i != e; ++i)
if (User->getValueType(i) == MVT::Other) {
Worklist.push_back(SDOperand(User, i));
break;
}
}
// Finally, legalize this node.
Select(Node);
}
// Select target instructions for the DAG.
DAG.setRoot(SelectRoot(DAG.getRoot()));
CodeGenMap.clear();
DAG.RemoveDeadNodes();
// Emit machine code to BB.
ScheduleAndEmitDAG(DAG);
}
/// getGlobalBaseReg - Output the instructions required to put the
/// base address to use for accessing globals into a register.
///
SDOperand PPCDAGToDAGISel::getGlobalBaseReg() {
if (!GlobalBaseReg) {
// Insert the set of GlobalBaseReg into the first MBB of the function
MachineBasicBlock &FirstMBB = BB->getParent()->front();
MachineBasicBlock::iterator MBBI = FirstMBB.begin();
SSARegMap *RegMap = BB->getParent()->getSSARegMap();
// FIXME: when we get to LP64, we will need to create the appropriate
// type of register here.
GlobalBaseReg = RegMap->createVirtualRegister(PPC::GPRCRegisterClass);
BuildMI(FirstMBB, MBBI, PPC::MovePCtoLR, 0, PPC::LR);
BuildMI(FirstMBB, MBBI, PPC::MFLR, 1, GlobalBaseReg);
}
return CurDAG->getRegister(GlobalBaseReg, MVT::i32);
}
// isIntImmediate - This method tests to see if a constant operand.
// If so Imm will receive the 32 bit value.
static bool isIntImmediate(SDNode *N, unsigned& Imm) {
if (N->getOpcode() == ISD::Constant) {
Imm = cast<ConstantSDNode>(N)->getValue();
return true;
}
return false;
}
// isRunOfOnes - Returns true iff Val consists of one contiguous run of 1s with
// any number of 0s on either side. The 1s are allowed to wrap from LSB to
// MSB, so 0x000FFF0, 0x0000FFFF, and 0xFF0000FF are all runs. 0x0F0F0000 is
// not, since all 1s are not contiguous.
static bool isRunOfOnes(unsigned Val, unsigned &MB, unsigned &ME) {
if (isShiftedMask_32(Val)) {
// look for the first non-zero bit
MB = CountLeadingZeros_32(Val);
// look for the first zero bit after the run of ones
ME = CountLeadingZeros_32((Val - 1) ^ Val);
return true;
} else {
Val = ~Val; // invert mask
if (isShiftedMask_32(Val)) {
// effectively look for the first zero bit
ME = CountLeadingZeros_32(Val) - 1;
// effectively look for the first one bit after the run of zeros
MB = CountLeadingZeros_32((Val - 1) ^ Val) + 1;
return true;
}
}
// no run present
return false;
}
// isRotateAndMask - Returns true if Mask and Shift can be folded into a rotate
// and mask opcode and mask operation.
static bool isRotateAndMask(SDNode *N, unsigned Mask, bool IsShiftMask,
unsigned &SH, unsigned &MB, unsigned &ME) {
// Don't even go down this path for i64, since different logic will be
// necessary for rldicl/rldicr/rldimi.
if (N->getValueType(0) != MVT::i32)
return false;
unsigned Shift = 32;
unsigned Indeterminant = ~0; // bit mask marking indeterminant results
unsigned Opcode = N->getOpcode();
if (N->getNumOperands() != 2 ||
!isIntImmediate(N->getOperand(1).Val, Shift) || (Shift > 31))
return false;
if (Opcode == ISD::SHL) {
// apply shift left to mask if it comes first
if (IsShiftMask) Mask = Mask << Shift;
// determine which bits are made indeterminant by shift
Indeterminant = ~(0xFFFFFFFFu << Shift);
} else if (Opcode == ISD::SRL) {
// apply shift right to mask if it comes first
if (IsShiftMask) Mask = Mask >> Shift;
// determine which bits are made indeterminant by shift
Indeterminant = ~(0xFFFFFFFFu >> Shift);
// adjust for the left rotate
Shift = 32 - Shift;
} else {
return false;
}
// if the mask doesn't intersect any Indeterminant bits
if (Mask && !(Mask & Indeterminant)) {
SH = Shift;
// make sure the mask is still a mask (wrap arounds may not be)
return isRunOfOnes(Mask, MB, ME);
}
return false;
}
// isOpcWithIntImmediate - This method tests to see if the node is a specific
// opcode and that it has a immediate integer right operand.
// If so Imm will receive the 32 bit value.
static bool isOpcWithIntImmediate(SDNode *N, unsigned Opc, unsigned& Imm) {
return N->getOpcode() == Opc && isIntImmediate(N->getOperand(1).Val, Imm);
}
// isIntImmediate - This method tests to see if a constant operand.
// If so Imm will receive the 32 bit value.
static bool isIntImmediate(SDOperand N, unsigned& Imm) {
if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N)) {
Imm = (unsigned)CN->getSignExtended();
return true;
}
return false;
}
/// SelectBitfieldInsert - turn an or of two masked values into
/// the rotate left word immediate then mask insert (rlwimi) instruction.
/// Returns true on success, false if the caller still needs to select OR.
///
/// Patterns matched:
/// 1. or shl, and 5. or and, and
/// 2. or and, shl 6. or shl, shr
/// 3. or shr, and 7. or shr, shl
/// 4. or and, shr
SDNode *PPCDAGToDAGISel::SelectBitfieldInsert(SDNode *N) {
bool IsRotate = false;
unsigned TgtMask = 0xFFFFFFFF, InsMask = 0xFFFFFFFF, SH = 0;
unsigned Value;
SDOperand Op0 = N->getOperand(0);
SDOperand Op1 = N->getOperand(1);
unsigned Op0Opc = Op0.getOpcode();
unsigned Op1Opc = Op1.getOpcode();
// Verify that we have the correct opcodes
if (ISD::SHL != Op0Opc && ISD::SRL != Op0Opc && ISD::AND != Op0Opc)
return false;
if (ISD::SHL != Op1Opc && ISD::SRL != Op1Opc && ISD::AND != Op1Opc)
return false;
// Generate Mask value for Target
if (isIntImmediate(Op0.getOperand(1), Value)) {
switch(Op0Opc) {
case ISD::SHL: TgtMask <<= Value; break;
case ISD::SRL: TgtMask >>= Value; break;
case ISD::AND: TgtMask &= Value; break;
}
} else {
return 0;
}
// Generate Mask value for Insert
if (!isIntImmediate(Op1.getOperand(1), Value))
return 0;
switch(Op1Opc) {
case ISD::SHL:
SH = Value;
InsMask <<= SH;
if (Op0Opc == ISD::SRL) IsRotate = true;
break;
case ISD::SRL:
SH = Value;
InsMask >>= SH;
SH = 32-SH;
if (Op0Opc == ISD::SHL) IsRotate = true;
break;
case ISD::AND:
InsMask &= Value;
break;
}
// If both of the inputs are ANDs and one of them has a logical shift by
// constant as its input, make that AND the inserted value so that we can
// combine the shift into the rotate part of the rlwimi instruction
bool IsAndWithShiftOp = false;
if (Op0Opc == ISD::AND && Op1Opc == ISD::AND) {
if (Op1.getOperand(0).getOpcode() == ISD::SHL ||
Op1.getOperand(0).getOpcode() == ISD::SRL) {
if (isIntImmediate(Op1.getOperand(0).getOperand(1), Value)) {
SH = Op1.getOperand(0).getOpcode() == ISD::SHL ? Value : 32 - Value;
IsAndWithShiftOp = true;
}
} else if (Op0.getOperand(0).getOpcode() == ISD::SHL ||
Op0.getOperand(0).getOpcode() == ISD::SRL) {
if (isIntImmediate(Op0.getOperand(0).getOperand(1), Value)) {
std::swap(Op0, Op1);
std::swap(TgtMask, InsMask);
SH = Op1.getOperand(0).getOpcode() == ISD::SHL ? Value : 32 - Value;
IsAndWithShiftOp = true;
}
}
}
// Verify that the Target mask and Insert mask together form a full word mask
// and that the Insert mask is a run of set bits (which implies both are runs
// of set bits). Given that, Select the arguments and generate the rlwimi
// instruction.
unsigned MB, ME;
if (((TgtMask & InsMask) == 0) && isRunOfOnes(InsMask, MB, ME)) {
bool fullMask = (TgtMask ^ InsMask) == 0xFFFFFFFF;
bool Op0IsAND = Op0Opc == ISD::AND;
// Check for rotlwi / rotrwi here, a special case of bitfield insert
// where both bitfield halves are sourced from the same value.
if (IsRotate && fullMask &&
N->getOperand(0).getOperand(0) == N->getOperand(1).getOperand(0)) {
Op0 = CurDAG->getTargetNode(PPC::RLWINM, MVT::i32,
Select(N->getOperand(0).getOperand(0)),
getI32Imm(SH), getI32Imm(0), getI32Imm(31));
return Op0.Val;
}
SDOperand Tmp1 = (Op0IsAND && fullMask) ? Select(Op0.getOperand(0))
: Select(Op0);
SDOperand Tmp2 = IsAndWithShiftOp ? Select(Op1.getOperand(0).getOperand(0))
: Select(Op1.getOperand(0));
Op0 = CurDAG->getTargetNode(PPC::RLWIMI, MVT::i32, Tmp1, Tmp2,
getI32Imm(SH), getI32Imm(MB), getI32Imm(ME));
return Op0.Val;
}
return 0;
}
/// SelectAddrImm - Returns true if the address N can be represented by
/// a base register plus a signed 16-bit displacement [r+imm].
bool PPCDAGToDAGISel::SelectAddrImm(SDOperand N, SDOperand &Disp,
SDOperand &Base) {
if (N.getOpcode() == ISD::ADD) {
unsigned imm = 0;
if (isIntImmediate(N.getOperand(1), imm) && isInt16(imm)) {
Disp = getI32Imm(imm & 0xFFFF);
if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(N.getOperand(0))) {
Base = CurDAG->getTargetFrameIndex(FI->getIndex(), MVT::i32);
} else {
Base = N.getOperand(0);
}
return true; // [r+i]
} else if (N.getOperand(1).getOpcode() == PPCISD::Lo) {
// Match LOAD (ADD (X, Lo(G))).
assert(!cast<ConstantSDNode>(N.getOperand(1).getOperand(1))->getValue()
&& "Cannot handle constant offsets yet!");
Disp = N.getOperand(1).getOperand(0); // The global address.
assert(Disp.getOpcode() == ISD::TargetGlobalAddress ||
Disp.getOpcode() == ISD::TargetConstantPool);
Base = N.getOperand(0);
return true; // [&g+r]
}
return false; // [r+r]
}
Disp = getI32Imm(0);
if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(N))
Base = CurDAG->getTargetFrameIndex(FI->getIndex(), MVT::i32);
else
Base = N;
return true; // [r+0]
}
/// SelectAddrIdx - Given the specified addressed, check to see if it can be
/// represented as an indexed [r+r] operation. Returns false if it can
/// be represented by [r+imm], which are preferred.
bool PPCDAGToDAGISel::SelectAddrIdx(SDOperand N, SDOperand &Base,
SDOperand &Index) {
// Check to see if we can represent this as an [r+imm] address instead,
// which will fail if the address is more profitably represented as an
// [r+r] address.
if (SelectAddrImm(N, Base, Index))
return false;
if (N.getOpcode() == ISD::ADD) {
Base = N.getOperand(0);
Index = N.getOperand(1);
return true;
}
Base = CurDAG->getRegister(PPC::R0, MVT::i32);
Index = N;
return true;
}
/// SelectAddrIdxOnly - Given the specified addressed, force it to be
/// represented as an indexed [r+r] operation.
bool PPCDAGToDAGISel::SelectAddrIdxOnly(SDOperand N, SDOperand &Base,
SDOperand &Index) {
if (N.getOpcode() == ISD::ADD) {
Base = N.getOperand(0);
Index = N.getOperand(1);
return true;
}
Base = CurDAG->getRegister(PPC::R0, MVT::i32);
Index = N;
return true;
}
/// SelectCC - Select a comparison of the specified values with the specified
/// condition code, returning the CR# of the expression.
SDOperand PPCDAGToDAGISel::SelectCC(SDOperand LHS, SDOperand RHS,
ISD::CondCode CC) {
// Always select the LHS.
LHS = Select(LHS);
// Use U to determine whether the SETCC immediate range is signed or not.
if (MVT::isInteger(LHS.getValueType())) {
bool U = ISD::isUnsignedIntSetCC(CC);
unsigned Imm;
if (isIntImmediate(RHS, Imm) &&
((U && isUInt16(Imm)) || (!U && isInt16(Imm))))
return CurDAG->getTargetNode(U ? PPC::CMPLWI : PPC::CMPWI, MVT::i32,
LHS, getI32Imm(Imm & 0xFFFF));
return CurDAG->getTargetNode(U ? PPC::CMPLW : PPC::CMPW, MVT::i32,
LHS, Select(RHS));
} else if (LHS.getValueType() == MVT::f32) {
return CurDAG->getTargetNode(PPC::FCMPUS, MVT::i32, LHS, Select(RHS));
} else {
return CurDAG->getTargetNode(PPC::FCMPUD, MVT::i32, LHS, Select(RHS));
}
}
/// getBCCForSetCC - Returns the PowerPC condition branch mnemonic corresponding
/// to Condition.
static unsigned getBCCForSetCC(ISD::CondCode CC) {
switch (CC) {
default: assert(0 && "Unknown condition!"); abort();
case ISD::SETOEQ: // FIXME: This is incorrect see PR642.
case ISD::SETEQ: return PPC::BEQ;
case ISD::SETONE: // FIXME: This is incorrect see PR642.
case ISD::SETNE: return PPC::BNE;
case ISD::SETOLT: // FIXME: This is incorrect see PR642.
case ISD::SETULT:
case ISD::SETLT: return PPC::BLT;
case ISD::SETOLE: // FIXME: This is incorrect see PR642.
case ISD::SETULE:
case ISD::SETLE: return PPC::BLE;
case ISD::SETOGT: // FIXME: This is incorrect see PR642.
case ISD::SETUGT:
case ISD::SETGT: return PPC::BGT;
case ISD::SETOGE: // FIXME: This is incorrect see PR642.
case ISD::SETUGE:
case ISD::SETGE: return PPC::BGE;
case ISD::SETO: return PPC::BUN;
case ISD::SETUO: return PPC::BNU;
}
return 0;
}
/// getCRIdxForSetCC - Return the index of the condition register field
/// associated with the SetCC condition, and whether or not the field is
/// treated as inverted. That is, lt = 0; ge = 0 inverted.
static unsigned getCRIdxForSetCC(ISD::CondCode CC, bool& Inv) {
switch (CC) {
default: assert(0 && "Unknown condition!"); abort();
case ISD::SETOLT: // FIXME: This is incorrect see PR642.
case ISD::SETULT:
case ISD::SETLT: Inv = false; return 0;
case ISD::SETOGE: // FIXME: This is incorrect see PR642.
case ISD::SETUGE:
case ISD::SETGE: Inv = true; return 0;
case ISD::SETOGT: // FIXME: This is incorrect see PR642.
case ISD::SETUGT:
case ISD::SETGT: Inv = false; return 1;
case ISD::SETOLE: // FIXME: This is incorrect see PR642.
case ISD::SETULE:
case ISD::SETLE: Inv = true; return 1;
case ISD::SETOEQ: // FIXME: This is incorrect see PR642.
case ISD::SETEQ: Inv = false; return 2;
case ISD::SETONE: // FIXME: This is incorrect see PR642.
case ISD::SETNE: Inv = true; return 2;
case ISD::SETO: Inv = true; return 3;
case ISD::SETUO: Inv = false; return 3;
}
return 0;
}
SDOperand PPCDAGToDAGISel::SelectADD_PARTS(SDOperand Op) {
SDNode *N = Op.Val;
SDOperand LHSL = Select(N->getOperand(0));
SDOperand LHSH = Select(N->getOperand(1));
unsigned Imm;
bool ME = false, ZE = false;
if (isIntImmediate(N->getOperand(3), Imm)) {
ME = (signed)Imm == -1;
ZE = Imm == 0;
}
std::vector<SDOperand> Result;
SDOperand CarryFromLo;
if (isIntImmediate(N->getOperand(2), Imm) &&
((signed)Imm >= -32768 || (signed)Imm < 32768)) {
// Codegen the low 32 bits of the add. Interestingly, there is no
// shifted form of add immediate carrying.
CarryFromLo = CurDAG->getTargetNode(PPC::ADDIC, MVT::i32, MVT::Flag,
LHSL, getI32Imm(Imm));
} else {
CarryFromLo = CurDAG->getTargetNode(PPC::ADDC, MVT::i32, MVT::Flag,
LHSL, Select(N->getOperand(2)));
}
CarryFromLo = CarryFromLo.getValue(1);
// Codegen the high 32 bits, adding zero, minus one, or the full value
// along with the carry flag produced by addc/addic.
SDOperand ResultHi;
if (ZE)
ResultHi = CurDAG->getTargetNode(PPC::ADDZE, MVT::i32, LHSH, CarryFromLo);
else if (ME)
ResultHi = CurDAG->getTargetNode(PPC::ADDME, MVT::i32, LHSH, CarryFromLo);
else
ResultHi = CurDAG->getTargetNode(PPC::ADDE, MVT::i32, LHSH,
Select(N->getOperand(3)), CarryFromLo);
Result.push_back(CarryFromLo.getValue(0));
Result.push_back(ResultHi);
CodeGenMap[Op.getValue(0)] = Result[0];
CodeGenMap[Op.getValue(1)] = Result[1];
return Result[Op.ResNo];
}
SDOperand PPCDAGToDAGISel::SelectSUB_PARTS(SDOperand Op) {
SDNode *N = Op.Val;
SDOperand LHSL = Select(N->getOperand(0));
SDOperand LHSH = Select(N->getOperand(1));
SDOperand RHSL = Select(N->getOperand(2));
SDOperand RHSH = Select(N->getOperand(3));
std::vector<SDOperand> Result;
Result.push_back(CurDAG->getTargetNode(PPC::SUBFC, MVT::i32, MVT::Flag,
RHSL, LHSL));
Result.push_back(CurDAG->getTargetNode(PPC::SUBFE, MVT::i32, RHSH, LHSH,
Result[0].getValue(1)));
CodeGenMap[Op.getValue(0)] = Result[0];
CodeGenMap[Op.getValue(1)] = Result[1];
return Result[Op.ResNo];
}
SDOperand PPCDAGToDAGISel::SelectSETCC(SDOperand Op) {
SDNode *N = Op.Val;
unsigned Imm;
ISD::CondCode CC = cast<CondCodeSDNode>(N->getOperand(2))->get();
if (isIntImmediate(N->getOperand(1), Imm)) {
// We can codegen setcc op, imm very efficiently compared to a brcond.
// Check for those cases here.
// setcc op, 0
if (Imm == 0) {
SDOperand Op = Select(N->getOperand(0));
switch (CC) {
default: break;
case ISD::SETEQ:
Op = CurDAG->getTargetNode(PPC::CNTLZW, MVT::i32, Op);
return CurDAG->SelectNodeTo(N, PPC::RLWINM, MVT::i32, Op, getI32Imm(27),
getI32Imm(5), getI32Imm(31));
case ISD::SETNE: {
SDOperand AD = CurDAG->getTargetNode(PPC::ADDIC, MVT::i32, MVT::Flag,
Op, getI32Imm(~0U));
return CurDAG->SelectNodeTo(N, PPC::SUBFE, MVT::i32, AD, Op,
AD.getValue(1));
}
case ISD::SETLT:
return CurDAG->SelectNodeTo(N, PPC::RLWINM, MVT::i32, Op, getI32Imm(1),
getI32Imm(31), getI32Imm(31));
case ISD::SETGT: {
SDOperand T = CurDAG->getTargetNode(PPC::NEG, MVT::i32, Op);
T = CurDAG->getTargetNode(PPC::ANDC, MVT::i32, T, Op);;
return CurDAG->SelectNodeTo(N, PPC::RLWINM, MVT::i32, T, getI32Imm(1),
getI32Imm(31), getI32Imm(31));
}
}
} else if (Imm == ~0U) { // setcc op, -1
SDOperand Op = Select(N->getOperand(0));
switch (CC) {
default: break;
case ISD::SETEQ:
Op = CurDAG->getTargetNode(PPC::ADDIC, MVT::i32, MVT::Flag,
Op, getI32Imm(1));
return CurDAG->SelectNodeTo(N, PPC::ADDZE, MVT::i32,
CurDAG->getTargetNode(PPC::LI, MVT::i32,
getI32Imm(0)),
Op.getValue(1));
case ISD::SETNE: {
Op = CurDAG->getTargetNode(PPC::NOR, MVT::i32, Op, Op);
SDOperand AD = CurDAG->getTargetNode(PPC::ADDIC, MVT::i32, MVT::Flag,
Op, getI32Imm(~0U));
return CurDAG->SelectNodeTo(N, PPC::SUBFE, MVT::i32, AD, Op,
AD.getValue(1));
}
case ISD::SETLT: {
SDOperand AD = CurDAG->getTargetNode(PPC::ADDI, MVT::i32, Op,
getI32Imm(1));
SDOperand AN = CurDAG->getTargetNode(PPC::AND, MVT::i32, AD, Op);
return CurDAG->SelectNodeTo(N, PPC::RLWINM, MVT::i32, AN, getI32Imm(1),
getI32Imm(31), getI32Imm(31));
}
case ISD::SETGT:
Op = CurDAG->getTargetNode(PPC::RLWINM, MVT::i32, Op, getI32Imm(1),
getI32Imm(31), getI32Imm(31));
return CurDAG->SelectNodeTo(N, PPC::XORI, MVT::i32, Op, getI32Imm(1));
}
}
}
bool Inv;
unsigned Idx = getCRIdxForSetCC(CC, Inv);
SDOperand CCReg = SelectCC(N->getOperand(0), N->getOperand(1), CC);
SDOperand IntCR;
// Force the ccreg into CR7.
SDOperand CR7Reg = CurDAG->getRegister(PPC::CR7, MVT::i32);
SDOperand InFlag(0, 0); // Null incoming flag value.
CCReg = CurDAG->getCopyToReg(CurDAG->getEntryNode(), CR7Reg, CCReg,
InFlag).getValue(1);
if (TLI.getTargetMachine().getSubtarget<PPCSubtarget>().isGigaProcessor())
IntCR = CurDAG->getTargetNode(PPC::MFOCRF, MVT::i32, CR7Reg, CCReg);
else
IntCR = CurDAG->getTargetNode(PPC::MFCR, MVT::i32, CCReg);
if (!Inv) {
return CurDAG->SelectNodeTo(N, PPC::RLWINM, MVT::i32, IntCR,
getI32Imm((32-(3-Idx)) & 31),
getI32Imm(31), getI32Imm(31));
} else {
SDOperand Tmp =
CurDAG->getTargetNode(PPC::RLWINM, MVT::i32, IntCR,
getI32Imm((32-(3-Idx)) & 31),
getI32Imm(31),getI32Imm(31));
return CurDAG->SelectNodeTo(N, PPC::XORI, MVT::i32, Tmp, getI32Imm(1));
}
}
/// isCallCompatibleAddress - Return true if the specified 32-bit value is
/// representable in the immediate field of a Bx instruction.
static bool isCallCompatibleAddress(ConstantSDNode *C) {
int Addr = C->getValue();
if (Addr & 3) return false; // Low 2 bits are implicitly zero.
return (Addr << 6 >> 6) == Addr; // Top 6 bits have to be sext of immediate.
}
SDOperand PPCDAGToDAGISel::SelectCALL(SDOperand Op) {
SDNode *N = Op.Val;
SDOperand Chain = Select(N->getOperand(0));
unsigned CallOpcode;
std::vector<SDOperand> CallOperands;
if (GlobalAddressSDNode *GASD =
dyn_cast<GlobalAddressSDNode>(N->getOperand(1))) {
CallOpcode = PPC::BL;
CallOperands.push_back(N->getOperand(1));
} else if (ExternalSymbolSDNode *ESSDN =
dyn_cast<ExternalSymbolSDNode>(N->getOperand(1))) {
CallOpcode = PPC::BL;
CallOperands.push_back(N->getOperand(1));
} else if (isa<ConstantSDNode>(N->getOperand(1)) &&
isCallCompatibleAddress(cast<ConstantSDNode>(N->getOperand(1)))) {
ConstantSDNode *C = cast<ConstantSDNode>(N->getOperand(1));
CallOpcode = PPC::BLA;
CallOperands.push_back(getI32Imm((int)C->getValue() >> 2));
} else {
// Copy the callee address into the CTR register.
SDOperand Callee = Select(N->getOperand(1));
Chain = CurDAG->getTargetNode(PPC::MTCTR, MVT::Other, Callee, Chain);
// Copy the callee address into R12 on darwin.
SDOperand R12 = CurDAG->getRegister(PPC::R12, MVT::i32);
Chain = CurDAG->getNode(ISD::CopyToReg, MVT::Other, Chain, R12, Callee);
CallOperands.push_back(R12);
CallOpcode = PPC::BCTRL;
}
unsigned GPR_idx = 0, FPR_idx = 0;
static const unsigned GPR[] = {
PPC::R3, PPC::R4, PPC::R5, PPC::R6,
PPC::R7, PPC::R8, PPC::R9, PPC::R10,
};
static const unsigned FPR[] = {
PPC::F1, PPC::F2, PPC::F3, PPC::F4, PPC::F5, PPC::F6, PPC::F7,
PPC::F8, PPC::F9, PPC::F10, PPC::F11, PPC::F12, PPC::F13
};
SDOperand InFlag; // Null incoming flag value.
for (unsigned i = 2, e = N->getNumOperands(); i != e; ++i) {
unsigned DestReg = 0;
MVT::ValueType RegTy = N->getOperand(i).getValueType();
if (RegTy == MVT::i32) {
assert(GPR_idx < 8 && "Too many int args");
DestReg = GPR[GPR_idx++];
} else {
assert(MVT::isFloatingPoint(N->getOperand(i).getValueType()) &&
"Unpromoted integer arg?");
assert(FPR_idx < 13 && "Too many fp args");
DestReg = FPR[FPR_idx++];
}
if (N->getOperand(i).getOpcode() != ISD::UNDEF) {
SDOperand Val = Select(N->getOperand(i));
Chain = CurDAG->getCopyToReg(Chain, DestReg, Val, InFlag);
InFlag = Chain.getValue(1);
CallOperands.push_back(CurDAG->getRegister(DestReg, RegTy));
}
}
// Finally, once everything is in registers to pass to the call, emit the
// call itself.
if (InFlag.Val)
CallOperands.push_back(InFlag); // Strong dep on register copies.
else
CallOperands.push_back(Chain); // Weak dep on whatever occurs before
Chain = CurDAG->getTargetNode(CallOpcode, MVT::Other, MVT::Flag,
CallOperands);
std::vector<SDOperand> CallResults;
// If the call has results, copy the values out of the ret val registers.
switch (N->getValueType(0)) {
default: assert(0 && "Unexpected ret value!");
case MVT::Other: break;
case MVT::i32:
if (N->getValueType(1) == MVT::i32) {
Chain = CurDAG->getCopyFromReg(Chain, PPC::R4, MVT::i32,
Chain.getValue(1)).getValue(1);
CallResults.push_back(Chain.getValue(0));
Chain = CurDAG->getCopyFromReg(Chain, PPC::R3, MVT::i32,
Chain.getValue(2)).getValue(1);
CallResults.push_back(Chain.getValue(0));
} else {
Chain = CurDAG->getCopyFromReg(Chain, PPC::R3, MVT::i32,
Chain.getValue(1)).getValue(1);
CallResults.push_back(Chain.getValue(0));
}
break;
case MVT::f32:
case MVT::f64:
Chain = CurDAG->getCopyFromReg(Chain, PPC::F1, N->getValueType(0),
Chain.getValue(1)).getValue(1);
CallResults.push_back(Chain.getValue(0));
break;
}
CallResults.push_back(Chain);
for (unsigned i = 0, e = CallResults.size(); i != e; ++i)
CodeGenMap[Op.getValue(i)] = CallResults[i];
return CallResults[Op.ResNo];
}
// Select - Convert the specified operand from a target-independent to a
// target-specific node if it hasn't already been changed.
SDOperand PPCDAGToDAGISel::Select(SDOperand Op) {
SDNode *N = Op.Val;
if (N->getOpcode() >= ISD::BUILTIN_OP_END &&
N->getOpcode() < PPCISD::FIRST_NUMBER)
return Op; // Already selected.
// If this has already been converted, use it.
std::map<SDOperand, SDOperand>::iterator CGMI = CodeGenMap.find(Op);
if (CGMI != CodeGenMap.end()) return CGMI->second;
switch (N->getOpcode()) {
default: break;
case ISD::ADD_PARTS: return SelectADD_PARTS(Op);
case ISD::SUB_PARTS: return SelectSUB_PARTS(Op);
case ISD::SETCC: return SelectSETCC(Op);
case PPCISD::CALL: return SelectCALL(Op);
case PPCISD::GlobalBaseReg: return getGlobalBaseReg();
case ISD::FrameIndex: {
int FI = cast<FrameIndexSDNode>(N)->getIndex();
if (N->hasOneUse())
return CurDAG->SelectNodeTo(N, PPC::ADDI, MVT::i32,
CurDAG->getTargetFrameIndex(FI, MVT::i32),
getI32Imm(0));
return CodeGenMap[Op] =
CurDAG->getTargetNode(PPC::ADDI, MVT::i32,
CurDAG->getTargetFrameIndex(FI, MVT::i32),
getI32Imm(0));
}
case ISD::SDIV: {
// FIXME: since this depends on the setting of the carry flag from the srawi
// we should really be making notes about that for the scheduler.
// FIXME: It sure would be nice if we could cheaply recognize the
// srl/add/sra pattern the dag combiner will generate for this as
// sra/addze rather than having to handle sdiv ourselves. oh well.
unsigned Imm;
if (isIntImmediate(N->getOperand(1), Imm)) {
if ((signed)Imm > 0 && isPowerOf2_32(Imm)) {
SDOperand Op =
CurDAG->getTargetNode(PPC::SRAWI, MVT::i32, MVT::Flag,
Select(N->getOperand(0)),
getI32Imm(Log2_32(Imm)));
return CurDAG->SelectNodeTo(N, PPC::ADDZE, MVT::i32,
Op.getValue(0), Op.getValue(1));
} else if ((signed)Imm < 0 && isPowerOf2_32(-Imm)) {
SDOperand Op =
CurDAG->getTargetNode(PPC::SRAWI, MVT::i32, MVT::Flag,
Select(N->getOperand(0)),
getI32Imm(Log2_32(-Imm)));
SDOperand PT =
CurDAG->getTargetNode(PPC::ADDZE, MVT::i32, Op.getValue(0),
Op.getValue(1));
return CurDAG->SelectNodeTo(N, PPC::NEG, MVT::i32, PT);
}
}
// Other cases are autogenerated.
break;
}
case ISD::AND: {
unsigned Imm, Imm2;
// If this is an and of a value rotated between 0 and 31 bits and then and'd
// with a mask, emit rlwinm
if (isIntImmediate(N->getOperand(1), Imm) && (isShiftedMask_32(Imm) ||
isShiftedMask_32(~Imm))) {
SDOperand Val;
unsigned SH, MB, ME;
if (isRotateAndMask(N->getOperand(0).Val, Imm, false, SH, MB, ME)) {
Val = Select(N->getOperand(0).getOperand(0));
} else if (Imm == 0) {
// AND X, 0 -> 0, not "rlwinm 32".
return Select(N->getOperand(1));
} else {
Val = Select(N->getOperand(0));
isRunOfOnes(Imm, MB, ME);
SH = 0;
}
return CurDAG->SelectNodeTo(N, PPC::RLWINM, MVT::i32, Val, getI32Imm(SH),
getI32Imm(MB), getI32Imm(ME));
}
// ISD::OR doesn't get all the bitfield insertion fun.
// (and (or x, c1), c2) where isRunOfOnes(~(c1^c2)) is a bitfield insert
if (isIntImmediate(N->getOperand(1), Imm) &&
N->getOperand(0).getOpcode() == ISD::OR &&
isIntImmediate(N->getOperand(0).getOperand(1), Imm2)) {
unsigned MB, ME;
Imm = ~(Imm^Imm2);
if (isRunOfOnes(Imm, MB, ME)) {
SDOperand Tmp1 = Select(N->getOperand(0).getOperand(0));
SDOperand Tmp2 = Select(N->getOperand(0).getOperand(1));
return CurDAG->getTargetNode(PPC::RLWIMI, MVT::i32, Tmp1, Tmp2,
getI32Imm(0), getI32Imm(MB), getI32Imm(ME));
}
}
// Other cases are autogenerated.
break;
}
case ISD::OR:
if (SDNode *I = SelectBitfieldInsert(N))
return CodeGenMap[Op] = SDOperand(I, 0);
// Other cases are autogenerated.
break;
case ISD::SHL: {
unsigned Imm, SH, MB, ME;
if (isOpcWithIntImmediate(N->getOperand(0).Val, ISD::AND, Imm) &&
isRotateAndMask(N, Imm, true, SH, MB, ME)) {
return CurDAG->SelectNodeTo(N, PPC::RLWINM, MVT::i32,
Select(N->getOperand(0).getOperand(0)),
getI32Imm(SH), getI32Imm(MB), getI32Imm(ME));
}
// Other cases are autogenerated.
break;
}
case ISD::SRL: {
unsigned Imm, SH, MB, ME;
if (isOpcWithIntImmediate(N->getOperand(0).Val, ISD::AND, Imm) &&
isRotateAndMask(N, Imm, true, SH, MB, ME)) {
return CurDAG->SelectNodeTo(N, PPC::RLWINM, MVT::i32,
Select(N->getOperand(0).getOperand(0)),
getI32Imm(SH & 0x1F), getI32Imm(MB),
getI32Imm(ME));
}
// Other cases are autogenerated.
break;
}
case ISD::SELECT_CC: {
ISD::CondCode CC = cast<CondCodeSDNode>(N->getOperand(4))->get();
// handle the setcc cases here. select_cc lhs, 0, 1, 0, cc
if (ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N->getOperand(1)))
if (ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N->getOperand(2)))
if (ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N->getOperand(3)))
if (N1C->isNullValue() && N3C->isNullValue() &&
N2C->getValue() == 1ULL && CC == ISD::SETNE) {
SDOperand LHS = Select(N->getOperand(0));
SDOperand Tmp =
CurDAG->getTargetNode(PPC::ADDIC, MVT::i32, MVT::Flag,
LHS, getI32Imm(~0U));
return CurDAG->SelectNodeTo(N, PPC::SUBFE, MVT::i32, Tmp, LHS,
Tmp.getValue(1));
}
SDOperand CCReg = SelectCC(N->getOperand(0), N->getOperand(1), CC);
unsigned BROpc = getBCCForSetCC(CC);
bool isFP = MVT::isFloatingPoint(N->getValueType(0));
unsigned SelectCCOp;
if (MVT::isInteger(N->getValueType(0)))
SelectCCOp = PPC::SELECT_CC_Int;
else if (N->getValueType(0) == MVT::f32)
SelectCCOp = PPC::SELECT_CC_F4;
else
SelectCCOp = PPC::SELECT_CC_F8;
return CurDAG->SelectNodeTo(N, SelectCCOp, N->getValueType(0), CCReg,
Select(N->getOperand(2)),
Select(N->getOperand(3)),
getI32Imm(BROpc));
}
case ISD::BR_CC:
case ISD::BRTWOWAY_CC: {
SDOperand Chain = Select(N->getOperand(0));
MachineBasicBlock *Dest =
cast<BasicBlockSDNode>(N->getOperand(4))->getBasicBlock();
ISD::CondCode CC = cast<CondCodeSDNode>(N->getOperand(1))->get();
SDOperand CondCode = SelectCC(N->getOperand(2), N->getOperand(3), CC);
// If this is a two way branch, then grab the fallthrough basic block
// argument and build a PowerPC branch pseudo-op, suitable for long branch
// conversion if necessary by the branch selection pass. Otherwise, emit a
// standard conditional branch.
if (N->getOpcode() == ISD::BRTWOWAY_CC) {
SDOperand CondTrueBlock = N->getOperand(4);
SDOperand CondFalseBlock = N->getOperand(5);
// If the false case is the current basic block, then this is a self loop.
// We do not want to emit "Loop: ... brcond Out; br Loop", as it adds an
// extra dispatch group to the loop. Instead, invert the condition and
// emit "Loop: ... br!cond Loop; br Out
if (cast<BasicBlockSDNode>(CondFalseBlock)->getBasicBlock() == BB) {
std::swap(CondTrueBlock, CondFalseBlock);
CC = getSetCCInverse(CC,
MVT::isInteger(N->getOperand(2).getValueType()));
}
unsigned Opc = getBCCForSetCC(CC);
SDOperand CB = CurDAG->getTargetNode(PPC::COND_BRANCH, MVT::Other,
CondCode, getI32Imm(Opc),
CondTrueBlock, CondFalseBlock,
Chain);
return CurDAG->SelectNodeTo(N, PPC::B, MVT::Other, CondFalseBlock, CB);
} else {
// Iterate to the next basic block
ilist<MachineBasicBlock>::iterator It = BB;
++It;
// If the fallthrough path is off the end of the function, which would be
// undefined behavior, set it to be the same as the current block because
// we have nothing better to set it to, and leaving it alone will cause
// the PowerPC Branch Selection pass to crash.
if (It == BB->getParent()->end()) It = Dest;
return CurDAG->SelectNodeTo(N, PPC::COND_BRANCH, MVT::Other, CondCode,
getI32Imm(getBCCForSetCC(CC)),
N->getOperand(4), CurDAG->getBasicBlock(It),
Chain);
}
}
}
return SelectCode(Op);
}
/// createPPCISelDag - This pass converts a legalized DAG into a
/// PowerPC-specific DAG, ready for instruction scheduling.
///
FunctionPass *llvm::createPPCISelDag(TargetMachine &TM) {
return new PPCDAGToDAGISel(TM);
}
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