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llvm-6502/lib/Target/PowerPC/PPCISelDAGToDAG.cpp

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//===-- PPC32ISelDAGToDAG.cpp - PPC32 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 32 bit PowerPC,
// converting from a legalized dag to a PPC dag.
//
//===----------------------------------------------------------------------===//
#include "PowerPC.h"
#include "PPC32TargetMachine.h"
#include "PPC32ISelLowering.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
using namespace llvm;
namespace {
Statistic<> Recorded("ppc-codegen", "Number of recording ops emitted");
Statistic<> FusedFP ("ppc-codegen", "Number of fused fp operations");
Statistic<> FrameOff("ppc-codegen", "Number of frame idx offsets collapsed");
//===--------------------------------------------------------------------===//
/// PPC32DAGToDAGISel - PPC32 specific code to select PPC32 machine
/// instructions for SelectionDAG operations.
///
class PPC32DAGToDAGISel : public SelectionDAGISel {
PPC32TargetLowering PPC32Lowering;
unsigned GlobalBaseReg;
bool GlobalBaseInitialized;
public:
PPC32DAGToDAGISel(TargetMachine &TM)
: SelectionDAGISel(PPC32Lowering), PPC32Lowering(TM) {}
/// runOnFunction - Override this function in order to reset our
/// per-function variables.
virtual bool runOnFunction(Function &Fn) {
// Make sure we re-emit a set of the global base reg if necessary
GlobalBaseInitialized = false;
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);
}
// 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 *SelectIntImmediateExpr(SDOperand LHS, SDOperand RHS,
unsigned OCHi, unsigned OCLo,
bool IsArithmetic = false,
bool Negate = false);
/// InstructionSelectBasicBlock - This callback is invoked by
/// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
virtual void InstructionSelectBasicBlock(SelectionDAG &DAG) {
DEBUG(BB->dump());
// Codegen the basic block.
Select(DAG.getRoot());
DAG.RemoveDeadNodes();
DAG.viewGraph();
}
virtual const char *getPassName() const {
return "PowerPC DAG->DAG Pattern Instruction Selection";
}
};
}
// 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;
}
// isOprShiftImm - Returns true if the specified operand is a shift opcode with
// a immediate shift count less than 32.
static bool isOprShiftImm(SDNode *N, unsigned& Opc, unsigned& SH) {
Opc = N->getOpcode();
return (Opc == ISD::SHL || Opc == ISD::SRL || Opc == ISD::SRA) &&
isIntImmediate(N->getOperand(1).Val, SH) && SH < 32;
}
// 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 if (isShiftedMask_32(Val = ~Val)) { // invert mask
// 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 in to a rotate
// and mask opcode and mask operation.
static bool isRotateAndMask(SDNode *N, unsigned Mask, bool IsShiftMask,
unsigned &SH, unsigned &MB, unsigned &ME) {
unsigned Shift = 32;
unsigned Indeterminant = ~0; // bit mask marking indeterminant results
unsigned Opcode = N->getOpcode();
if (!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::SRA || 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);
}
// isOprNot - Returns true if the specified operand is an xor with immediate -1.
static bool isOprNot(SDNode *N) {
unsigned Imm;
return isOpcWithIntImmediate(N, ISD::XOR, Imm) && (signed)Imm == -1;
}
// Immediate constant composers.
// Lo16 - grabs the lo 16 bits from a 32 bit constant.
// Hi16 - grabs the hi 16 bits from a 32 bit constant.
// HA16 - computes the hi bits required if the lo bits are add/subtracted in
// arithmethically.
static unsigned Lo16(unsigned x) { return x & 0x0000FFFF; }
static unsigned Hi16(unsigned x) { return Lo16(x >> 16); }
static unsigned HA16(unsigned x) { return Hi16((signed)x - (signed short)x); }
// 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;
}
// SelectIntImmediateExpr - Choose code for integer operations with an immediate
// operand.
SDNode *PPC32DAGToDAGISel::SelectIntImmediateExpr(SDOperand LHS, SDOperand RHS,
unsigned OCHi, unsigned OCLo,
bool IsArithmetic,
bool Negate) {
// Check to make sure this is a constant.
ConstantSDNode *CN = dyn_cast<ConstantSDNode>(RHS);
// Exit if not a constant.
if (!CN) return 0;
// Extract immediate.
unsigned C = (unsigned)CN->getValue();
// Negate if required (ISD::SUB).
if (Negate) C = -C;
// Get the hi and lo portions of constant.
unsigned Hi = IsArithmetic ? HA16(C) : Hi16(C);
unsigned Lo = Lo16(C);
// If two instructions are needed and usage indicates it would be better to
// load immediate into a register, bail out.
if (Hi && Lo && CN->use_size() > 2) return false;
// Select the first operand.
SDOperand Opr0 = Select(LHS);
if (Lo) // Add in the lo-part.
Opr0 = CurDAG->getTargetNode(OCLo, MVT::i32, Opr0, getI32Imm(Lo));
if (Hi) // Add in the hi-part.
Opr0 = CurDAG->getTargetNode(OCHi, MVT::i32, Opr0, getI32Imm(Hi));
return Opr0.Val;
}
// Select - Convert the specified operand from a target-independent to a
// target-specific node if it hasn't already been changed.
SDOperand PPC32DAGToDAGISel::Select(SDOperand Op) {
SDNode *N = Op.Val;
if (N->getOpcode() >= ISD::BUILTIN_OP_END)
return Op; // Already selected.
switch (N->getOpcode()) {
default:
std::cerr << "Cannot yet select: ";
N->dump();
std::cerr << "\n";
abort();
case ISD::EntryToken: // These leaves remain the same.
case ISD::UNDEF:
return Op;
case ISD::TokenFactor: {
SDOperand New;
if (N->getNumOperands() == 2) {
SDOperand Op0 = Select(N->getOperand(0));
SDOperand Op1 = Select(N->getOperand(1));
New = CurDAG->getNode(ISD::TokenFactor, MVT::Other, Op0, Op1);
} else {
std::vector<SDOperand> Ops;
for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
Ops.push_back(Select(N->getOperand(0)));
New = CurDAG->getNode(ISD::TokenFactor, MVT::Other, Ops);
}
if (New.Val != N) {
CurDAG->ReplaceAllUsesWith(N, New.Val);
N = New.Val;
}
break;
}
case ISD::CopyFromReg: {
SDOperand Chain = Select(N->getOperand(0));
if (Chain == N->getOperand(0)) return Op; // No change
SDOperand New = CurDAG->getCopyFromReg(Chain,
cast<RegisterSDNode>(N->getOperand(1))->getReg(), N->getValueType(0));
return New.getValue(Op.ResNo);
}
case ISD::CopyToReg: {
SDOperand Chain = Select(N->getOperand(0));
SDOperand Reg = N->getOperand(1);
SDOperand Val = Select(N->getOperand(2));
if (Chain != N->getOperand(0) || Val != N->getOperand(2)) {
SDOperand New = CurDAG->getNode(ISD::CopyToReg, MVT::Other,
Chain, Reg, Val);
CurDAG->ReplaceAllUsesWith(N, New.Val);
N = New.Val;
}
break;
}
case ISD::Constant: {
assert(N->getValueType(0) == MVT::i32);
unsigned v = (unsigned)cast<ConstantSDNode>(N)->getValue();
if ((unsigned)(short)v == v) {
CurDAG->SelectNodeTo(N, MVT::i32, PPC::LI, getI32Imm(v));
break;
} else {
SDOperand Top = CurDAG->getTargetNode(PPC::LIS, MVT::i32,
getI32Imm(unsigned(v) >> 16));
CurDAG->SelectNodeTo(N, MVT::i32, PPC::ORI, Top, getI32Imm(v & 0xFFFF));
break;
}
}
case ISD::SIGN_EXTEND_INREG:
switch(cast<VTSDNode>(N->getOperand(1))->getVT()) {
default: assert(0 && "Illegal type in SIGN_EXTEND_INREG"); break;
case MVT::i16:
CurDAG->SelectNodeTo(N, MVT::i32, PPC::EXTSH, Select(N->getOperand(0)));
break;
case MVT::i8:
CurDAG->SelectNodeTo(N, MVT::i32, PPC::EXTSB, Select(N->getOperand(0)));
break;
}
break;
case ISD::CTLZ:
assert(N->getValueType(0) == MVT::i32);
CurDAG->SelectNodeTo(N, MVT::i32, PPC::CNTLZW, Select(N->getOperand(0)));
break;
case ISD::ADD: {
MVT::ValueType Ty = N->getValueType(0);
if (Ty == MVT::i32) {
if (SDNode *I = SelectIntImmediateExpr(N->getOperand(0), N->getOperand(1),
PPC::ADDIS, PPC::ADDI, true)) {
CurDAG->ReplaceAllUsesWith(N, I);
N = I;
} else {
CurDAG->SelectNodeTo(N, Ty, PPC::ADD, Select(N->getOperand(0)),
Select(N->getOperand(1)));
}
break;
}
if (!NoExcessFPPrecision) { // Match FMA ops
if (N->getOperand(0).getOpcode() == ISD::MUL &&
N->getOperand(0).Val->hasOneUse()) {
++FusedFP; // Statistic
CurDAG->SelectNodeTo(N, Ty, Ty == MVT::f64 ? PPC::FMADD : PPC::FMADDS,
Select(N->getOperand(0).getOperand(0)),
Select(N->getOperand(0).getOperand(1)),
Select(N->getOperand(1)));
break;
} else if (N->getOperand(1).getOpcode() == ISD::MUL &&
N->getOperand(1).hasOneUse()) {
++FusedFP; // Statistic
CurDAG->SelectNodeTo(N, Ty, Ty == MVT::f64 ? PPC::FMADD : PPC::FMADDS,
Select(N->getOperand(1).getOperand(0)),
Select(N->getOperand(1).getOperand(1)),
Select(N->getOperand(0)));
break;
}
}
CurDAG->SelectNodeTo(N, Ty, Ty == MVT::f64 ? PPC::FADD : PPC::FADDS,
Select(N->getOperand(0)), Select(N->getOperand(1)));
break;
}
case ISD::SUB: {
MVT::ValueType Ty = N->getValueType(0);
if (Ty == MVT::i32) {
unsigned Imm;
if (isIntImmediate(N->getOperand(0), Imm) && isInt16(Imm)) {
CurDAG->SelectNodeTo(N, Ty, PPC::SUBFIC, Select(N->getOperand(1)),
getI32Imm(Lo16(Imm)));
break;
}
if (SDNode *I = SelectIntImmediateExpr(N->getOperand(0), N->getOperand(1),
PPC::ADDIS, PPC::ADDI, true, true)) {
CurDAG->ReplaceAllUsesWith(N, I);
N = I;
} else {
CurDAG->SelectNodeTo(N, Ty, PPC::SUBF, Select(N->getOperand(1)),
Select(N->getOperand(0)));
}
break;
}
if (!NoExcessFPPrecision) { // Match FMA ops
if (N->getOperand(0).getOpcode() == ISD::MUL &&
N->getOperand(0).Val->hasOneUse()) {
++FusedFP; // Statistic
CurDAG->SelectNodeTo(N, Ty, Ty == MVT::f64 ? PPC::FMSUB : PPC::FMSUBS,
Select(N->getOperand(0).getOperand(0)),
Select(N->getOperand(0).getOperand(1)),
Select(N->getOperand(1)));
break;
} else if (N->getOperand(1).getOpcode() == ISD::MUL &&
N->getOperand(1).Val->hasOneUse()) {
++FusedFP; // Statistic
CurDAG->SelectNodeTo(N, Ty, Ty == MVT::f64 ? PPC::FNMSUB : PPC::FNMSUBS,
Select(N->getOperand(1).getOperand(0)),
Select(N->getOperand(1).getOperand(1)),
Select(N->getOperand(0)));
break;
}
}
CurDAG->SelectNodeTo(N, Ty, Ty == MVT::f64 ? PPC::FSUB : PPC::FSUBS,
Select(N->getOperand(0)),
Select(N->getOperand(1)));
break;
}
case ISD::MUL: {
unsigned Imm, Opc;
if (isIntImmediate(N->getOperand(1), Imm) && isInt16(Imm)) {
CurDAG->SelectNodeTo(N, N->getValueType(0), PPC::MULLI,
Select(N->getOperand(0)), getI32Imm(Lo16(Imm)));
break;
}
switch (N->getValueType(0)) {
default: assert(0 && "Unhandled multiply type!");
case MVT::i32: Opc = PPC::MULLW; break;
case MVT::f32: Opc = PPC::FMULS; break;
case MVT::f64: Opc = PPC::FMUL; break;
}
CurDAG->SelectNodeTo(N, N->getValueType(0), Opc, Select(N->getOperand(0)),
Select(N->getOperand(1)));
break;
}
case ISD::MULHS:
assert(N->getValueType(0) == MVT::i32);
CurDAG->SelectNodeTo(N, MVT::i32, PPC::MULHW, Select(N->getOperand(0)),
Select(N->getOperand(1)));
break;
case ISD::MULHU:
assert(N->getValueType(0) == MVT::i32);
CurDAG->SelectNodeTo(N, MVT::i32, PPC::MULHWU, Select(N->getOperand(0)),
Select(N->getOperand(1)));
break;
case ISD::AND: {
unsigned Imm, SH, MB, ME;
// 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;
if (isRotateAndMask(N->getOperand(0).Val, Imm, false, SH, MB, ME)) {
Val = Select(N->getOperand(0).getOperand(0));
} else {
Val = Select(N->getOperand(0));
isRunOfOnes(Imm, MB, ME);
SH = 0;
}
CurDAG->SelectNodeTo(N, MVT::i32, PPC::RLWINM, Val, getI32Imm(SH),
getI32Imm(MB), getI32Imm(ME));
break;
}
// If this is an and with an immediate that isn't a mask, then codegen it as
// high and low 16 bit immediate ands.
if (SDNode *I = SelectIntImmediateExpr(N->getOperand(0),
N->getOperand(1),
PPC::ANDISo, PPC::ANDIo)) {
CurDAG->ReplaceAllUsesWith(N, I);
N = I;
break;
}
// Finally, check for the case where we are being asked to select
// and (not(a), b) or and (a, not(b)) which can be selected as andc.
if (isOprNot(N->getOperand(0).Val))
CurDAG->SelectNodeTo(N, MVT::i32, PPC::ANDC, Select(N->getOperand(1)),
Select(N->getOperand(0).getOperand(0)));
else if (isOprNot(N->getOperand(1).Val))
CurDAG->SelectNodeTo(N, MVT::i32, PPC::ANDC, Select(N->getOperand(0)),
Select(N->getOperand(1).getOperand(0)));
else
CurDAG->SelectNodeTo(N, MVT::i32, PPC::AND, Select(N->getOperand(0)),
Select(N->getOperand(1)));
break;
}
case ISD::XOR:
// Check whether or not this node is a logical 'not'. This is represented
// by llvm as a xor with the constant value -1 (all bits set). If this is a
// 'not', then fold 'or' into 'nor', and so forth for the supported ops.
if (isOprNot(N)) {
unsigned Opc;
SDOperand Val = Select(N->getOperand(0));
switch (Val.getTargetOpcode()) {
default: Opc = 0; break;
case PPC::OR: Opc = PPC::NOR; break;
case PPC::AND: Opc = PPC::NAND; break;
case PPC::XOR: Opc = PPC::EQV; break;
}
if (Opc)
CurDAG->SelectNodeTo(N, MVT::i32, Opc, Val.getOperand(0),
Val.getOperand(1));
else
CurDAG->SelectNodeTo(N, MVT::i32, PPC::NOR, Val, Val);
break;
}
// If this is a xor with an immediate other than -1, then codegen it as high
// and low 16 bit immediate xors.
if (SDNode *I = SelectIntImmediateExpr(N->getOperand(0),
N->getOperand(1),
PPC::XORIS, PPC::XORI)) {
CurDAG->ReplaceAllUsesWith(N, I);
N = I;
break;
}
// Finally, check for the case where we are being asked to select
// xor (not(a), b) which is equivalent to not(xor a, b), which is eqv
if (isOprNot(N->getOperand(0).Val))
CurDAG->SelectNodeTo(N, MVT::i32, PPC::EQV,
Select(N->getOperand(0).getOperand(0)),
Select(N->getOperand(1)));
else
CurDAG->SelectNodeTo(N, MVT::i32, PPC::XOR, Select(N->getOperand(0)),
Select(N->getOperand(1)));
break;
case ISD::FABS:
CurDAG->SelectNodeTo(N, N->getValueType(0), PPC::FABS,
Select(N->getOperand(0)));
break;
case ISD::FP_EXTEND:
assert(MVT::f64 == N->getValueType(0) &&
MVT::f32 == N->getOperand(0).getValueType() && "Illegal FP_EXTEND");
CurDAG->SelectNodeTo(N, MVT::f64, PPC::FMR, Select(N->getOperand(0)));
break;
case ISD::FP_ROUND:
assert(MVT::f32 == N->getValueType(0) &&
MVT::f64 == N->getOperand(0).getValueType() && "Illegal FP_ROUND");
CurDAG->SelectNodeTo(N, MVT::f32, PPC::FRSP, Select(N->getOperand(0)));
break;
case ISD::FNEG: {
SDOperand Val = Select(N->getOperand(0));
MVT::ValueType Ty = N->getValueType(0);
if (Val.Val->hasOneUse()) {
unsigned Opc;
switch (Val.getTargetOpcode()) {
default: Opc = 0; break;
case PPC::FABS: Opc = PPC::FNABS; break;
case PPC::FMADD: Opc = PPC::FNMADD; break;
case PPC::FMADDS: Opc = PPC::FNMADDS; break;
case PPC::FMSUB: Opc = PPC::FNMSUB; break;
case PPC::FMSUBS: Opc = PPC::FNMSUBS; break;
}
// If we inverted the opcode, then emit the new instruction with the
// inverted opcode and the original instruction's operands. Otherwise,
// fall through and generate a fneg instruction.
if (Opc) {
if (PPC::FNABS == Opc)
CurDAG->SelectNodeTo(N, Ty, Opc, Val.getOperand(0));
else
CurDAG->SelectNodeTo(N, Ty, Opc, Val.getOperand(0),
Val.getOperand(1), Val.getOperand(2));
break;
}
}
CurDAG->SelectNodeTo(N, Ty, PPC::FNEG, Val);
break;
}
case ISD::FSQRT: {
MVT::ValueType Ty = N->getValueType(0);
CurDAG->SelectNodeTo(N, Ty, Ty == MVT::f64 ? PPC::FSQRT : PPC::FSQRTS,
Select(N->getOperand(0)));
break;
}
case ISD::RET: {
SDOperand Chain = Select(N->getOperand(0)); // Token chain.
if (N->getNumOperands() > 1) {
SDOperand Val = Select(N->getOperand(1));
switch (N->getOperand(1).getValueType()) {
default: assert(0 && "Unknown return type!");
case MVT::f64:
case MVT::f32:
Chain = CurDAG->getCopyToReg(Chain, PPC::F1, Val);
break;
case MVT::i32:
Chain = CurDAG->getCopyToReg(Chain, PPC::R3, Val);
break;
}
if (N->getNumOperands() > 2) {
assert(N->getOperand(1).getValueType() == MVT::i32 &&
N->getOperand(2).getValueType() == MVT::i32 &&
N->getNumOperands() == 2 && "Unknown two-register ret value!");
Val = Select(N->getOperand(2));
Chain = CurDAG->getCopyToReg(Chain, PPC::R4, Val);
}
}
// Finally, select this to a blr (return) instruction.
CurDAG->SelectNodeTo(N, MVT::Other, PPC::BLR, Chain);
break;
}
}
return SDOperand(N, 0);
}
/// createPPC32ISelDag - This pass converts a legalized DAG into a
/// PowerPC-specific DAG, ready for instruction scheduling.
///
FunctionPass *llvm::createPPC32ISelDag(TargetMachine &TM) {
return new PPC32DAGToDAGISel(TM);
}