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llvm-6502/lib/Target/Alpha/AlphaISelDAGToDAG.cpp
Andrew Lenharth 40ec5037fa improved zap discovery 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26148 91177308-0d34-0410-b5e6-96231b3b80d8
2006-02-13 18:52:29 +00:00

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//===-- AlphaISelDAGToDAG.cpp - Alpha pattern matching inst selector ------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Andrew Lenharth 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 Alpha,
// converting from a legalized dag to a Alpha dag.
//
//===----------------------------------------------------------------------===//
#include "Alpha.h"
#include "AlphaTargetMachine.h"
#include "AlphaISelLowering.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFrameInfo.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 <algorithm>
#include <iostream>
#include <set>
using namespace llvm;
namespace {
//===--------------------------------------------------------------------===//
/// AlphaDAGToDAGISel - Alpha specific code to select Alpha machine
/// instructions for SelectionDAG operations.
class AlphaDAGToDAGISel : public SelectionDAGISel {
AlphaTargetLowering AlphaLowering;
static const int64_t IMM_LOW = -32768;
static const int64_t IMM_HIGH = 32767;
static const int64_t IMM_MULT = 65536;
static const int64_t IMM_FULLHIGH = IMM_HIGH + IMM_HIGH * IMM_MULT;
static const int64_t IMM_FULLLOW = IMM_LOW + IMM_LOW * IMM_MULT;
static int64_t get_ldah16(int64_t x) {
int64_t y = x / IMM_MULT;
if (x % IMM_MULT > IMM_HIGH)
++y;
return y;
}
static int64_t get_lda16(int64_t x) {
return x - get_ldah16(x) * IMM_MULT;
}
static uint64_t get_zapImm(uint64_t x) {
unsigned int build = 0;
for(int i = 0; i < 8; ++i)
{
if ((x & 0x00FF) == 0x00FF)
build |= 1 << i;
else if ((x & 0x00FF) != 0)
{ build = 0; break; }
x >>= 8;
}
return build;
}
static bool isFPZ(SDOperand N) {
ConstantFPSDNode *CN = dyn_cast<ConstantFPSDNode>(N);
return (CN && (CN->isExactlyValue(+0.0) || CN->isExactlyValue(-0.0)));
}
static bool isFPZn(SDOperand N) {
ConstantFPSDNode *CN = dyn_cast<ConstantFPSDNode>(N);
return (CN && CN->isExactlyValue(-0.0));
}
static bool isFPZp(SDOperand N) {
ConstantFPSDNode *CN = dyn_cast<ConstantFPSDNode>(N);
return (CN && CN->isExactlyValue(+0.0));
}
public:
AlphaDAGToDAGISel(TargetMachine &TM)
: SelectionDAGISel(AlphaLowering), AlphaLowering(TM)
{}
/// getI64Imm - Return a target constant with the specified value, of type
/// i64.
inline SDOperand getI64Imm(int64_t Imm) {
return CurDAG->getTargetConstant(Imm, MVT::i64);
}
// Select - Convert the specified operand from a target-independent to a
// target-specific node if it hasn't already been changed.
void Select(SDOperand &Result, SDOperand Op);
/// 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 "Alpha DAG->DAG Pattern Instruction Selection";
}
// Include the pieces autogenerated from the target description.
#include "AlphaGenDAGISel.inc"
private:
SDOperand getGlobalBaseReg();
SDOperand getRASaveReg();
SDOperand SelectCALL(SDOperand Op);
};
}
/// getGlobalBaseReg - Output the instructions required to put the
/// GOT address into a register.
///
SDOperand AlphaDAGToDAGISel::getGlobalBaseReg() {
return CurDAG->getCopyFromReg(CurDAG->getEntryNode(),
AlphaLowering.getVRegGP(),
MVT::i64);
}
/// getRASaveReg - Grab the return address
///
SDOperand AlphaDAGToDAGISel::getRASaveReg() {
return CurDAG->getCopyFromReg(CurDAG->getEntryNode(),
AlphaLowering.getVRegRA(),
MVT::i64);
}
/// InstructionSelectBasicBlock - This callback is invoked by
/// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
void AlphaDAGToDAGISel::InstructionSelectBasicBlock(SelectionDAG &DAG) {
DEBUG(BB->dump());
// Select target instructions for the DAG.
DAG.setRoot(SelectRoot(DAG.getRoot()));
CodeGenMap.clear();
DAG.RemoveDeadNodes();
// Emit machine code to BB.
ScheduleAndEmitDAG(DAG);
}
// Select - Convert the specified operand from a target-independent to a
// target-specific node if it hasn't already been changed.
void AlphaDAGToDAGISel::Select(SDOperand &Result, SDOperand Op) {
SDNode *N = Op.Val;
if (N->getOpcode() >= ISD::BUILTIN_OP_END &&
N->getOpcode() < AlphaISD::FIRST_NUMBER) {
Result = Op;
return; // Already selected.
}
// If this has already been converted, use it.
std::map<SDOperand, SDOperand>::iterator CGMI = CodeGenMap.find(Op);
if (CGMI != CodeGenMap.end()) {
Result = CGMI->second;
return;
}
switch (N->getOpcode()) {
default: break;
case AlphaISD::CALL:
Result = SelectCALL(Op);
return;
case ISD::FrameIndex: {
int FI = cast<FrameIndexSDNode>(N)->getIndex();
Result = CurDAG->SelectNodeTo(N, Alpha::LDA, MVT::i64,
CurDAG->getTargetFrameIndex(FI, MVT::i32),
getI64Imm(0));
return;
}
case AlphaISD::GlobalBaseReg:
Result = getGlobalBaseReg();
return;
case AlphaISD::DivCall: {
SDOperand Chain = CurDAG->getEntryNode();
SDOperand N0, N1, N2;
Select(N0, Op.getOperand(0));
Select(N1, Op.getOperand(1));
Select(N2, Op.getOperand(2));
Chain = CurDAG->getCopyToReg(Chain, Alpha::R24, N1,
SDOperand(0,0));
Chain = CurDAG->getCopyToReg(Chain, Alpha::R25, N2,
Chain.getValue(1));
Chain = CurDAG->getCopyToReg(Chain, Alpha::R27, N0,
Chain.getValue(1));
SDNode *CNode =
CurDAG->getTargetNode(Alpha::JSRs, MVT::Other, MVT::Flag,
Chain, Chain.getValue(1));
Chain = CurDAG->getCopyFromReg(Chain, Alpha::R27, MVT::i64,
SDOperand(CNode, 1));
Result = CurDAG->SelectNodeTo(N, Alpha::BIS, MVT::i64, Chain, Chain);
return;
}
case ISD::READCYCLECOUNTER: {
SDOperand Chain;
Select(Chain, N->getOperand(0)); //Select chain
Result = CurDAG->SelectNodeTo(N, Alpha::RPCC, MVT::i64, Chain);
return;
}
case ISD::RET: {
SDOperand Chain;
Select(Chain, N->getOperand(0)); // Token chain.
SDOperand InFlag;
if (N->getNumOperands() == 2) {
SDOperand Val;
Select(Val, N->getOperand(1));
if (N->getOperand(1).getValueType() == MVT::i64) {
Chain = CurDAG->getCopyToReg(Chain, Alpha::R0, Val, InFlag);
InFlag = Chain.getValue(1);
} else if (N->getOperand(1).getValueType() == MVT::f64 ||
N->getOperand(1).getValueType() == MVT::f32) {
Chain = CurDAG->getCopyToReg(Chain, Alpha::F0, Val, InFlag);
InFlag = Chain.getValue(1);
}
}
Chain = CurDAG->getCopyToReg(Chain, Alpha::R26, getRASaveReg(), InFlag);
InFlag = Chain.getValue(1);
// Finally, select this to a ret instruction.
Result = CurDAG->SelectNodeTo(N, Alpha::RETDAG, MVT::Other, Chain, InFlag);
return;
}
case ISD::Constant: {
uint64_t uval = cast<ConstantSDNode>(N)->getValue();
if (uval == 0) {
Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), Alpha::R31,
MVT::i64);
return;
}
int64_t val = (int64_t)uval;
int32_t val32 = (int32_t)val;
if (val <= IMM_HIGH + IMM_HIGH * IMM_MULT &&
val >= IMM_LOW + IMM_LOW * IMM_MULT)
break; //(LDAH (LDA))
if ((uval >> 32) == 0 && //empty upper bits
val32 <= IMM_HIGH + IMM_HIGH * IMM_MULT)
// val32 >= IMM_LOW + IMM_LOW * IMM_MULT) //always true
break; //(zext (LDAH (LDA)))
//Else use the constant pool
MachineConstantPool *CP = BB->getParent()->getConstantPool();
ConstantUInt *C =
ConstantUInt::get(Type::getPrimitiveType(Type::ULongTyID) , uval);
SDOperand CPI = CurDAG->getTargetConstantPool(C, MVT::i64);
SDNode *Tmp = CurDAG->getTargetNode(Alpha::LDAHr, MVT::i64, CPI,
getGlobalBaseReg());
Result = CurDAG->SelectNodeTo(N, Alpha::LDQr, MVT::i64, MVT::Other,
CPI, SDOperand(Tmp, 0), CurDAG->getEntryNode());
return;
}
case ISD::TargetConstantFP: {
ConstantFPSDNode *CN = cast<ConstantFPSDNode>(N);
bool isDouble = N->getValueType(0) == MVT::f64;
MVT::ValueType T = isDouble ? MVT::f64 : MVT::f32;
if (CN->isExactlyValue(+0.0)) {
Result = CurDAG->SelectNodeTo(N, isDouble ? Alpha::CPYST : Alpha::CPYSS,
T, CurDAG->getRegister(Alpha::F31, T),
CurDAG->getRegister(Alpha::F31, T));
return;
} else if ( CN->isExactlyValue(-0.0)) {
Result = CurDAG->SelectNodeTo(N, isDouble ? Alpha::CPYSNT : Alpha::CPYSNS,
T, CurDAG->getRegister(Alpha::F31, T),
CurDAG->getRegister(Alpha::F31, T));
return;
} else {
abort();
}
break;
}
case ISD::SETCC:
if (MVT::isFloatingPoint(N->getOperand(0).Val->getValueType(0))) {
unsigned Opc = Alpha::WTF;
ISD::CondCode CC = cast<CondCodeSDNode>(N->getOperand(2))->get();
bool rev = false;
bool isNE = false;
switch(CC) {
default: N->dump(); assert(0 && "Unknown FP comparison!");
case ISD::SETEQ: Opc = Alpha::CMPTEQ; break;
case ISD::SETLT: Opc = Alpha::CMPTLT; break;
case ISD::SETLE: Opc = Alpha::CMPTLE; break;
case ISD::SETGT: Opc = Alpha::CMPTLT; rev = true; break;
case ISD::SETGE: Opc = Alpha::CMPTLE; rev = true; break;
case ISD::SETNE: Opc = Alpha::CMPTEQ; isNE = true; break;
};
SDOperand tmp1, tmp2;
Select(tmp1, N->getOperand(0));
Select(tmp2, N->getOperand(1));
SDNode *cmp = CurDAG->getTargetNode(Opc, MVT::f64,
rev?tmp2:tmp1,
rev?tmp1:tmp2);
if (isNE)
cmp = CurDAG->getTargetNode(Alpha::CMPTEQ, MVT::f64, SDOperand(cmp, 0),
CurDAG->getRegister(Alpha::F31, MVT::f64));
SDOperand LD;
if (AlphaLowering.hasITOF()) {
LD = CurDAG->getNode(AlphaISD::FTOIT_, MVT::i64, SDOperand(cmp, 0));
} else {
int FrameIdx =
CurDAG->getMachineFunction().getFrameInfo()->CreateStackObject(8, 8);
SDOperand FI = CurDAG->getFrameIndex(FrameIdx, MVT::i64);
SDOperand ST =
SDOperand(CurDAG->getTargetNode(Alpha::STT, MVT::Other,
SDOperand(cmp, 0), FI,
CurDAG->getRegister(Alpha::R31, MVT::i64)), 0);
LD = SDOperand(CurDAG->getTargetNode(Alpha::LDQ, MVT::i64, FI,
CurDAG->getRegister(Alpha::R31, MVT::i64),
ST), 0);
}
Result = SDOperand(CurDAG->getTargetNode(Alpha::CMPULT, MVT::i64,
CurDAG->getRegister(Alpha::R31, MVT::i64),
LD), 0);
return;
}
break;
case ISD::SELECT:
if (MVT::isFloatingPoint(N->getValueType(0)) &&
(N->getOperand(0).getOpcode() != ISD::SETCC ||
!MVT::isFloatingPoint(N->getOperand(0).getOperand(1).getValueType()))) {
//This should be the condition not covered by the Patterns
//FIXME: Don't have SelectCode die, but rather return something testable
// so that things like this can be caught in fall though code
//move int to fp
bool isDouble = N->getValueType(0) == MVT::f64;
SDOperand LD, cond, TV, FV;
Select(cond, N->getOperand(0));
Select(TV, N->getOperand(1));
Select(FV, N->getOperand(2));
if (AlphaLowering.hasITOF()) {
LD = CurDAG->getNode(AlphaISD::ITOFT_, MVT::f64, cond);
} else {
int FrameIdx =
CurDAG->getMachineFunction().getFrameInfo()->CreateStackObject(8, 8);
SDOperand FI = CurDAG->getFrameIndex(FrameIdx, MVT::i64);
SDOperand ST =
SDOperand(CurDAG->getTargetNode(Alpha::STQ, MVT::Other,
cond, FI, CurDAG->getRegister(Alpha::R31, MVT::i64)), 0);
LD = SDOperand(CurDAG->getTargetNode(Alpha::LDT, MVT::f64, FI,
CurDAG->getRegister(Alpha::R31, MVT::i64),
ST), 0);
}
Result = SDOperand(CurDAG->getTargetNode(isDouble?Alpha::FCMOVNET:Alpha::FCMOVNES,
MVT::f64, FV, TV, LD), 0);
return;
}
break;
case ISD::AND: {
ConstantSDNode* SC;
ConstantSDNode* MC;
if (N->getOperand(0).getOpcode() == ISD::SRL &&
(MC = dyn_cast<ConstantSDNode>(N->getOperand(1))) &&
(SC = dyn_cast<ConstantSDNode>(N->getOperand(0).getOperand(1))))
{
uint64_t sval = SC->getValue();
uint64_t mval = MC->getValue();
if (get_zapImm(mval)) //the result is a zap, let the autogened stuff deal
break;
// given mask X, and shift S, we want to see if there is any zap in the mask
// if we play around with the botton S bits
uint64_t dontcare = (~0ULL) >> (64 - sval);
uint64_t mask = mval << sval;
if (get_zapImm(mask | dontcare))
mask = mask | dontcare;
if (get_zapImm(mask)) {
SDOperand Src;
Select(Src, N->getOperand(0).getOperand(0));
SDOperand Z =
SDOperand(CurDAG->getTargetNode(Alpha::ZAPNOTi, MVT::i64, Src,
getI64Imm(get_zapImm(mask))), 0);
Result = SDOperand(CurDAG->getTargetNode(Alpha::SRL, MVT::i64, Z,
getI64Imm(sval)), 0);
return;
}
}
break;
}
}
SelectCode(Result, Op);
}
SDOperand AlphaDAGToDAGISel::SelectCALL(SDOperand Op) {
//TODO: add flag stuff to prevent nondeturministic breakage!
SDNode *N = Op.Val;
SDOperand Chain;
SDOperand Addr = N->getOperand(1);
SDOperand InFlag; // Null incoming flag value.
Select(Chain, N->getOperand(0));
std::vector<SDOperand> CallOperands;
std::vector<MVT::ValueType> TypeOperands;
//grab the arguments
for(int i = 2, e = N->getNumOperands(); i < e; ++i) {
SDOperand Tmp;
TypeOperands.push_back(N->getOperand(i).getValueType());
Select(Tmp, N->getOperand(i));
CallOperands.push_back(Tmp);
}
int count = N->getNumOperands() - 2;
static const unsigned args_int[] = {Alpha::R16, Alpha::R17, Alpha::R18,
Alpha::R19, Alpha::R20, Alpha::R21};
static const unsigned args_float[] = {Alpha::F16, Alpha::F17, Alpha::F18,
Alpha::F19, Alpha::F20, Alpha::F21};
for (int i = 6; i < count; ++i) {
unsigned Opc = Alpha::WTF;
if (MVT::isInteger(TypeOperands[i])) {
Opc = Alpha::STQ;
} else if (TypeOperands[i] == MVT::f32) {
Opc = Alpha::STS;
} else if (TypeOperands[i] == MVT::f64) {
Opc = Alpha::STT;
} else
assert(0 && "Unknown operand");
Chain = SDOperand(CurDAG->getTargetNode(Opc, MVT::Other, CallOperands[i],
getI64Imm((i - 6) * 8),
CurDAG->getCopyFromReg(Chain, Alpha::R30, MVT::i64),
Chain), 0);
}
for (int i = 0; i < std::min(6, count); ++i) {
if (MVT::isInteger(TypeOperands[i])) {
Chain = CurDAG->getCopyToReg(Chain, args_int[i], CallOperands[i], InFlag);
InFlag = Chain.getValue(1);
} else if (TypeOperands[i] == MVT::f32 || TypeOperands[i] == MVT::f64) {
Chain = CurDAG->getCopyToReg(Chain, args_float[i], CallOperands[i], InFlag);
InFlag = Chain.getValue(1);
} else
assert(0 && "Unknown operand");
}
// Finally, once everything is in registers to pass to the call, emit the
// call itself.
if (Addr.getOpcode() == AlphaISD::GPRelLo) {
SDOperand GOT = getGlobalBaseReg();
Chain = CurDAG->getCopyToReg(Chain, Alpha::R29, GOT, InFlag);
InFlag = Chain.getValue(1);
Chain = SDOperand(CurDAG->getTargetNode(Alpha::BSR, MVT::Other, MVT::Flag,
Addr.getOperand(0), Chain, InFlag), 0);
} else {
Select(Addr, Addr);
Chain = CurDAG->getCopyToReg(Chain, Alpha::R27, Addr, InFlag);
InFlag = Chain.getValue(1);
Chain = SDOperand(CurDAG->getTargetNode(Alpha::JSR, MVT::Other, MVT::Flag,
Chain, InFlag), 0);
}
InFlag = Chain.getValue(1);
std::vector<SDOperand> CallResults;
switch (N->getValueType(0)) {
default: assert(0 && "Unexpected ret value!");
case MVT::Other: break;
case MVT::i64:
Chain = CurDAG->getCopyFromReg(Chain, Alpha::R0, MVT::i64, InFlag).getValue(1);
CallResults.push_back(Chain.getValue(0));
break;
case MVT::f32:
Chain = CurDAG->getCopyFromReg(Chain, Alpha::F0, MVT::f32, InFlag).getValue(1);
CallResults.push_back(Chain.getValue(0));
break;
case MVT::f64:
Chain = CurDAG->getCopyFromReg(Chain, Alpha::F0, MVT::f64, InFlag).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];
}
/// createAlphaISelDag - This pass converts a legalized DAG into a
/// Alpha-specific DAG, ready for instruction scheduling.
///
FunctionPass *llvm::createAlphaISelDag(TargetMachine &TM) {
return new AlphaDAGToDAGISel(TM);
}
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