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llvm-mirror/lib/Target/X86/X86ISelDAGToDAG.cpp
Evan Cheng f18016728c On x86 favors folding short immediate into some arithmetic operations (e.g. add, and, xor, etc.) because materializing an immediate in a register is expensive in turns of code size. 
e.g.
movl 4(%esp), %eax
addl $4, %eax

is 2 bytes shorter than

movl $4, %eax
addl 4(%esp), %eax

llvm-svn: 60139
2008-11-27 00:49:46 +00:00

1597 lines
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//===- X86ISelDAGToDAG.cpp - A DAG pattern matching inst selector for X86 -===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a DAG pattern matching instruction selector for X86,
// converting from a legalized dag to a X86 dag.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "x86-isel"
#include "X86.h"
#include "X86InstrBuilder.h"
#include "X86ISelLowering.h"
#include "X86MachineFunctionInfo.h"
#include "X86RegisterInfo.h"
#include "X86Subtarget.h"
#include "X86TargetMachine.h"
#include "llvm/GlobalValue.h"
#include "llvm/Instructions.h"
#include "llvm/Intrinsics.h"
#include "llvm/Support/CFG.h"
#include "llvm/Type.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Streams.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm;
STATISTIC(NumLoadMoved, "Number of loads moved below TokenFactor");
//===----------------------------------------------------------------------===//
// Pattern Matcher Implementation
//===----------------------------------------------------------------------===//
namespace {
/// X86ISelAddressMode - This corresponds to X86AddressMode, but uses
/// SDValue's instead of register numbers for the leaves of the matched
/// tree.
struct X86ISelAddressMode {
enum {
RegBase,
FrameIndexBase
} BaseType;
struct { // This is really a union, discriminated by BaseType!
SDValue Reg;
int FrameIndex;
} Base;
bool isRIPRel; // RIP as base?
unsigned Scale;
SDValue IndexReg;
int32_t Disp;
GlobalValue *GV;
Constant *CP;
const char *ES;
int JT;
unsigned Align; // CP alignment.
X86ISelAddressMode()
: BaseType(RegBase), isRIPRel(false), Scale(1), IndexReg(), Disp(0),
GV(0), CP(0), ES(0), JT(-1), Align(0) {
}
void dump() {
cerr << "X86ISelAddressMode " << this << "\n";
cerr << "Base.Reg ";
if (Base.Reg.getNode() != 0) Base.Reg.getNode()->dump();
else cerr << "nul";
cerr << " Base.FrameIndex " << Base.FrameIndex << "\n";
cerr << "isRIPRel " << isRIPRel << " Scale" << Scale << "\n";
cerr << "IndexReg ";
if (IndexReg.getNode() != 0) IndexReg.getNode()->dump();
else cerr << "nul";
cerr << " Disp " << Disp << "\n";
cerr << "GV "; if (GV) GV->dump();
else cerr << "nul";
cerr << " CP "; if (CP) CP->dump();
else cerr << "nul";
cerr << "\n";
cerr << "ES "; if (ES) cerr << ES; else cerr << "nul";
cerr << " JT" << JT << " Align" << Align << "\n";
}
};
}
namespace {
//===--------------------------------------------------------------------===//
/// ISel - X86 specific code to select X86 machine instructions for
/// SelectionDAG operations.
///
class VISIBILITY_HIDDEN X86DAGToDAGISel : public SelectionDAGISel {
/// TM - Keep a reference to X86TargetMachine.
///
X86TargetMachine &TM;
/// X86Lowering - This object fully describes how to lower LLVM code to an
/// X86-specific SelectionDAG.
X86TargetLowering &X86Lowering;
/// Subtarget - Keep a pointer to the X86Subtarget around so that we can
/// make the right decision when generating code for different targets.
const X86Subtarget *Subtarget;
/// CurBB - Current BB being isel'd.
///
MachineBasicBlock *CurBB;
/// OptForSize - If true, selector should try to optimize for code size
/// instead of performance.
bool OptForSize;
public:
X86DAGToDAGISel(X86TargetMachine &tm, bool fast)
: SelectionDAGISel(*tm.getTargetLowering(), fast),
TM(tm), X86Lowering(*TM.getTargetLowering()),
Subtarget(&TM.getSubtarget<X86Subtarget>()),
OptForSize(false) {}
virtual const char *getPassName() const {
return "X86 DAG->DAG Instruction Selection";
}
/// InstructionSelect - This callback is invoked by
/// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
virtual void InstructionSelect();
virtual void EmitFunctionEntryCode(Function &Fn, MachineFunction &MF);
virtual
bool IsLegalAndProfitableToFold(SDNode *N, SDNode *U, SDNode *Root) const;
// Include the pieces autogenerated from the target description.
#include "X86GenDAGISel.inc"
private:
SDNode *Select(SDValue N);
SDNode *SelectAtomic64(SDNode *Node, unsigned Opc);
bool MatchAddress(SDValue N, X86ISelAddressMode &AM,
bool isRoot = true, unsigned Depth = 0);
bool MatchAddressBase(SDValue N, X86ISelAddressMode &AM,
bool isRoot, unsigned Depth);
bool SelectAddr(SDValue Op, SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index, SDValue &Disp);
bool SelectLEAAddr(SDValue Op, SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index, SDValue &Disp);
bool SelectScalarSSELoad(SDValue Op, SDValue Pred,
SDValue N, SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp,
SDValue &InChain, SDValue &OutChain);
bool TryFoldLoad(SDValue P, SDValue N,
SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp);
void PreprocessForRMW();
void PreprocessForFPConvert();
/// SelectInlineAsmMemoryOperand - Implement addressing mode selection for
/// inline asm expressions.
virtual bool SelectInlineAsmMemoryOperand(const SDValue &Op,
char ConstraintCode,
std::vector<SDValue> &OutOps);
void EmitSpecialCodeForMain(MachineBasicBlock *BB, MachineFrameInfo *MFI);
inline void getAddressOperands(X86ISelAddressMode &AM, SDValue &Base,
SDValue &Scale, SDValue &Index,
SDValue &Disp) {
Base = (AM.BaseType == X86ISelAddressMode::FrameIndexBase) ?
CurDAG->getTargetFrameIndex(AM.Base.FrameIndex, TLI.getPointerTy()) :
AM.Base.Reg;
Scale = getI8Imm(AM.Scale);
Index = AM.IndexReg;
// These are 32-bit even in 64-bit mode since RIP relative offset
// is 32-bit.
if (AM.GV)
Disp = CurDAG->getTargetGlobalAddress(AM.GV, MVT::i32, AM.Disp);
else if (AM.CP)
Disp = CurDAG->getTargetConstantPool(AM.CP, MVT::i32,
AM.Align, AM.Disp);
else if (AM.ES)
Disp = CurDAG->getTargetExternalSymbol(AM.ES, MVT::i32);
else if (AM.JT != -1)
Disp = CurDAG->getTargetJumpTable(AM.JT, MVT::i32);
else
Disp = CurDAG->getTargetConstant(AM.Disp, MVT::i32);
}
/// getI8Imm - Return a target constant with the specified value, of type
/// i8.
inline SDValue getI8Imm(unsigned Imm) {
return CurDAG->getTargetConstant(Imm, MVT::i8);
}
/// getI16Imm - Return a target constant with the specified value, of type
/// i16.
inline SDValue getI16Imm(unsigned Imm) {
return CurDAG->getTargetConstant(Imm, MVT::i16);
}
/// getI32Imm - Return a target constant with the specified value, of type
/// i32.
inline SDValue getI32Imm(unsigned Imm) {
return CurDAG->getTargetConstant(Imm, MVT::i32);
}
/// getGlobalBaseReg - Return an SDNode that returns the value of
/// the global base register. Output instructions required to
/// initialize the global base register, if necessary.
///
SDNode *getGlobalBaseReg();
/// getTruncateTo8Bit - return an SDNode that implements a subreg based
/// truncate of the specified operand to i8. This can be done with tablegen,
/// except that this code uses MVT::Flag in a tricky way that happens to
/// improve scheduling in some cases.
SDNode *getTruncateTo8Bit(SDValue N0);
#ifndef NDEBUG
unsigned Indent;
#endif
};
}
/// findFlagUse - Return use of MVT::Flag value produced by the specified
/// SDNode.
///
static SDNode *findFlagUse(SDNode *N) {
unsigned FlagResNo = N->getNumValues()-1;
for (SDNode::use_iterator I = N->use_begin(), E = N->use_end(); I != E; ++I) {
SDNode *User = *I;
for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) {
SDValue Op = User->getOperand(i);
if (Op.getNode() == N && Op.getResNo() == FlagResNo)
return User;
}
}
return NULL;
}
/// findNonImmUse - Return true by reference in "found" if "Use" is an
/// non-immediate use of "Def". This function recursively traversing
/// up the operand chain ignoring certain nodes.
static void findNonImmUse(SDNode *Use, SDNode* Def, SDNode *ImmedUse,
SDNode *Root, bool &found,
SmallPtrSet<SDNode*, 16> &Visited) {
if (found ||
Use->getNodeId() < Def->getNodeId() ||
!Visited.insert(Use))
return;
for (unsigned i = 0, e = Use->getNumOperands(); !found && i != e; ++i) {
SDNode *N = Use->getOperand(i).getNode();
if (N == Def) {
if (Use == ImmedUse || Use == Root)
continue; // We are not looking for immediate use.
assert(N != Root);
found = true;
break;
}
// Traverse up the operand chain.
findNonImmUse(N, Def, ImmedUse, Root, found, Visited);
}
}
/// isNonImmUse - Start searching from Root up the DAG to check is Def can
/// be reached. Return true if that's the case. However, ignore direct uses
/// by ImmedUse (which would be U in the example illustrated in
/// IsLegalAndProfitableToFold) and by Root (which can happen in the store
/// case).
/// FIXME: to be really generic, we should allow direct use by any node
/// that is being folded. But realisticly since we only fold loads which
/// have one non-chain use, we only need to watch out for load/op/store
/// and load/op/cmp case where the root (store / cmp) may reach the load via
/// its chain operand.
static inline bool isNonImmUse(SDNode *Root, SDNode *Def, SDNode *ImmedUse) {
SmallPtrSet<SDNode*, 16> Visited;
bool found = false;
findNonImmUse(Root, Def, ImmedUse, Root, found, Visited);
return found;
}
bool X86DAGToDAGISel::IsLegalAndProfitableToFold(SDNode *N, SDNode *U,
SDNode *Root) const {
if (Fast) return false;
if (U == Root)
switch (U->getOpcode()) {
default: break;
case ISD::ADD:
case ISD::ADDC:
case ISD::ADDE:
case ISD::AND:
case ISD::OR:
case ISD::XOR: {
// If the other operand is a 8-bit immediate we should fold the immediate
// instead. This reduces code size.
// e.g.
// movl 4(%esp), %eax
// addl $4, %eax
// vs.
// movl $4, %eax
// addl 4(%esp), %eax
// The former is 2 bytes shorter. In case where the increment is 1, then
// the saving can be 4 bytes (by using incl %eax).
ConstantSDNode *Imm = dyn_cast<ConstantSDNode>(U->getOperand(1));
if (Imm) {
if (U->getValueType(0) == MVT::i64) {
if ((int32_t)Imm->getZExtValue() == (int64_t)Imm->getZExtValue())
return false;
} else {
if ((int8_t)Imm->getZExtValue() == (int64_t)Imm->getZExtValue())
return false;
}
}
}
}
// If Root use can somehow reach N through a path that that doesn't contain
// U then folding N would create a cycle. e.g. In the following
// diagram, Root can reach N through X. If N is folded into into Root, then
// X is both a predecessor and a successor of U.
//
// [N*] //
// ^ ^ //
// / \ //
// [U*] [X]? //
// ^ ^ //
// \ / //
// \ / //
// [Root*] //
//
// * indicates nodes to be folded together.
//
// If Root produces a flag, then it gets (even more) interesting. Since it
// will be "glued" together with its flag use in the scheduler, we need to
// check if it might reach N.
//
// [N*] //
// ^ ^ //
// / \ //
// [U*] [X]? //
// ^ ^ //
// \ \ //
// \ | //
// [Root*] | //
// ^ | //
// f | //
// | / //
// [Y] / //
// ^ / //
// f / //
// | / //
// [FU] //
//
// If FU (flag use) indirectly reaches N (the load), and Root folds N
// (call it Fold), then X is a predecessor of FU and a successor of
// Fold. But since Fold and FU are flagged together, this will create
// a cycle in the scheduling graph.
MVT VT = Root->getValueType(Root->getNumValues()-1);
while (VT == MVT::Flag) {
SDNode *FU = findFlagUse(Root);
if (FU == NULL)
break;
Root = FU;
VT = Root->getValueType(Root->getNumValues()-1);
}
return !isNonImmUse(Root, N, U);
}
/// MoveBelowTokenFactor - Replace TokenFactor operand with load's chain operand
/// and move load below the TokenFactor. Replace store's chain operand with
/// load's chain result.
static void MoveBelowTokenFactor(SelectionDAG *CurDAG, SDValue Load,
SDValue Store, SDValue TF) {
SmallVector<SDValue, 4> Ops;
for (unsigned i = 0, e = TF.getNode()->getNumOperands(); i != e; ++i)
if (Load.getNode() == TF.getOperand(i).getNode())
Ops.push_back(Load.getOperand(0));
else
Ops.push_back(TF.getOperand(i));
CurDAG->UpdateNodeOperands(TF, &Ops[0], Ops.size());
CurDAG->UpdateNodeOperands(Load, TF, Load.getOperand(1), Load.getOperand(2));
CurDAG->UpdateNodeOperands(Store, Load.getValue(1), Store.getOperand(1),
Store.getOperand(2), Store.getOperand(3));
}
/// isRMWLoad - Return true if N is a load that's part of RMW sub-DAG.
///
static bool isRMWLoad(SDValue N, SDValue Chain, SDValue Address,
SDValue &Load) {
if (N.getOpcode() == ISD::BIT_CONVERT)
N = N.getOperand(0);
LoadSDNode *LD = dyn_cast<LoadSDNode>(N);
if (!LD || LD->isVolatile())
return false;
if (LD->getAddressingMode() != ISD::UNINDEXED)
return false;
ISD::LoadExtType ExtType = LD->getExtensionType();
if (ExtType != ISD::NON_EXTLOAD && ExtType != ISD::EXTLOAD)
return false;
if (N.hasOneUse() &&
N.getOperand(1) == Address &&
N.getNode()->isOperandOf(Chain.getNode())) {
Load = N;
return true;
}
return false;
}
/// MoveBelowCallSeqStart - Replace CALLSEQ_START operand with load's chain
/// operand and move load below the call's chain operand.
static void MoveBelowCallSeqStart(SelectionDAG *CurDAG, SDValue Load,
SDValue Call, SDValue Chain) {
SmallVector<SDValue, 8> Ops;
for (unsigned i = 0, e = Chain.getNode()->getNumOperands(); i != e; ++i)
if (Load.getNode() == Chain.getOperand(i).getNode())
Ops.push_back(Load.getOperand(0));
else
Ops.push_back(Chain.getOperand(i));
CurDAG->UpdateNodeOperands(Chain, &Ops[0], Ops.size());
CurDAG->UpdateNodeOperands(Load, Call.getOperand(0),
Load.getOperand(1), Load.getOperand(2));
Ops.clear();
Ops.push_back(SDValue(Load.getNode(), 1));
for (unsigned i = 1, e = Call.getNode()->getNumOperands(); i != e; ++i)
Ops.push_back(Call.getOperand(i));
CurDAG->UpdateNodeOperands(Call, &Ops[0], Ops.size());
}
/// isCalleeLoad - Return true if call address is a load and it can be
/// moved below CALLSEQ_START and the chains leading up to the call.
/// Return the CALLSEQ_START by reference as a second output.
static bool isCalleeLoad(SDValue Callee, SDValue &Chain) {
if (Callee.getNode() == Chain.getNode() || !Callee.hasOneUse())
return false;
LoadSDNode *LD = dyn_cast<LoadSDNode>(Callee.getNode());
if (!LD ||
LD->isVolatile() ||
LD->getAddressingMode() != ISD::UNINDEXED ||
LD->getExtensionType() != ISD::NON_EXTLOAD)
return false;
// Now let's find the callseq_start.
while (Chain.getOpcode() != ISD::CALLSEQ_START) {
if (!Chain.hasOneUse())
return false;
Chain = Chain.getOperand(0);
}
return Chain.getOperand(0).getNode() == Callee.getNode();
}
/// PreprocessForRMW - Preprocess the DAG to make instruction selection better.
/// This is only run if not in -fast mode (aka -O0).
/// This allows the instruction selector to pick more read-modify-write
/// instructions. This is a common case:
///
/// [Load chain]
/// ^
/// |
/// [Load]
/// ^ ^
/// | |
/// / \-
/// / |
/// [TokenFactor] [Op]
/// ^ ^
/// | |
/// \ /
/// \ /
/// [Store]
///
/// The fact the store's chain operand != load's chain will prevent the
/// (store (op (load))) instruction from being selected. We can transform it to:
///
/// [Load chain]
/// ^
/// |
/// [TokenFactor]
/// ^
/// |
/// [Load]
/// ^ ^
/// | |
/// | \-
/// | |
/// | [Op]
/// | ^
/// | |
/// \ /
/// \ /
/// [Store]
void X86DAGToDAGISel::PreprocessForRMW() {
for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(),
E = CurDAG->allnodes_end(); I != E; ++I) {
if (I->getOpcode() == X86ISD::CALL) {
/// Also try moving call address load from outside callseq_start to just
/// before the call to allow it to be folded.
///
/// [Load chain]
/// ^
/// |
/// [Load]
/// ^ ^
/// | |
/// / \--
/// / |
///[CALLSEQ_START] |
/// ^ |
/// | |
/// [LOAD/C2Reg] |
/// | |
/// \ /
/// \ /
/// [CALL]
SDValue Chain = I->getOperand(0);
SDValue Load = I->getOperand(1);
if (!isCalleeLoad(Load, Chain))
continue;
MoveBelowCallSeqStart(CurDAG, Load, SDValue(I, 0), Chain);
++NumLoadMoved;
continue;
}
if (!ISD::isNON_TRUNCStore(I))
continue;
SDValue Chain = I->getOperand(0);
if (Chain.getNode()->getOpcode() != ISD::TokenFactor)
continue;
SDValue N1 = I->getOperand(1);
SDValue N2 = I->getOperand(2);
if ((N1.getValueType().isFloatingPoint() &&
!N1.getValueType().isVector()) ||
!N1.hasOneUse())
continue;
bool RModW = false;
SDValue Load;
unsigned Opcode = N1.getNode()->getOpcode();
switch (Opcode) {
case ISD::ADD:
case ISD::MUL:
case ISD::AND:
case ISD::OR:
case ISD::XOR:
case ISD::ADDC:
case ISD::ADDE:
case ISD::VECTOR_SHUFFLE: {
SDValue N10 = N1.getOperand(0);
SDValue N11 = N1.getOperand(1);
RModW = isRMWLoad(N10, Chain, N2, Load);
if (!RModW)
RModW = isRMWLoad(N11, Chain, N2, Load);
break;
}
case ISD::SUB:
case ISD::SHL:
case ISD::SRA:
case ISD::SRL:
case ISD::ROTL:
case ISD::ROTR:
case ISD::SUBC:
case ISD::SUBE:
case X86ISD::SHLD:
case X86ISD::SHRD: {
SDValue N10 = N1.getOperand(0);
RModW = isRMWLoad(N10, Chain, N2, Load);
break;
}
}
if (RModW) {
MoveBelowTokenFactor(CurDAG, Load, SDValue(I, 0), Chain);
++NumLoadMoved;
}
}
}
/// PreprocessForFPConvert - Walk over the dag lowering fpround and fpextend
/// nodes that target the FP stack to be store and load to the stack. This is a
/// gross hack. We would like to simply mark these as being illegal, but when
/// we do that, legalize produces these when it expands calls, then expands
/// these in the same legalize pass. We would like dag combine to be able to
/// hack on these between the call expansion and the node legalization. As such
/// this pass basically does "really late" legalization of these inline with the
/// X86 isel pass.
void X86DAGToDAGISel::PreprocessForFPConvert() {
for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(),
E = CurDAG->allnodes_end(); I != E; ) {
SDNode *N = I++; // Preincrement iterator to avoid invalidation issues.
if (N->getOpcode() != ISD::FP_ROUND && N->getOpcode() != ISD::FP_EXTEND)
continue;
// If the source and destination are SSE registers, then this is a legal
// conversion that should not be lowered.
MVT SrcVT = N->getOperand(0).getValueType();
MVT DstVT = N->getValueType(0);
bool SrcIsSSE = X86Lowering.isScalarFPTypeInSSEReg(SrcVT);
bool DstIsSSE = X86Lowering.isScalarFPTypeInSSEReg(DstVT);
if (SrcIsSSE && DstIsSSE)
continue;
if (!SrcIsSSE && !DstIsSSE) {
// If this is an FPStack extension, it is a noop.
if (N->getOpcode() == ISD::FP_EXTEND)
continue;
// If this is a value-preserving FPStack truncation, it is a noop.
if (N->getConstantOperandVal(1))
continue;
}
// Here we could have an FP stack truncation or an FPStack <-> SSE convert.
// FPStack has extload and truncstore. SSE can fold direct loads into other
// operations. Based on this, decide what we want to do.
MVT MemVT;
if (N->getOpcode() == ISD::FP_ROUND)
MemVT = DstVT; // FP_ROUND must use DstVT, we can't do a 'trunc load'.
else
MemVT = SrcIsSSE ? SrcVT : DstVT;
SDValue MemTmp = CurDAG->CreateStackTemporary(MemVT);
// FIXME: optimize the case where the src/dest is a load or store?
SDValue Store = CurDAG->getTruncStore(CurDAG->getEntryNode(),
N->getOperand(0),
MemTmp, NULL, 0, MemVT);
SDValue Result = CurDAG->getExtLoad(ISD::EXTLOAD, DstVT, Store, MemTmp,
NULL, 0, MemVT);
// We're about to replace all uses of the FP_ROUND/FP_EXTEND with the
// extload we created. This will cause general havok on the dag because
// anything below the conversion could be folded into other existing nodes.
// To avoid invalidating 'I', back it up to the convert node.
--I;
CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Result);
// Now that we did that, the node is dead. Increment the iterator to the
// next node to process, then delete N.
++I;
CurDAG->DeleteNode(N);
}
}
/// InstructionSelectBasicBlock - This callback is invoked by SelectionDAGISel
/// when it has created a SelectionDAG for us to codegen.
void X86DAGToDAGISel::InstructionSelect() {
CurBB = BB; // BB can change as result of isel.
const Function *F = CurDAG->getMachineFunction().getFunction();
OptForSize = F->hasFnAttr(Attribute::OptimizeForSize);
DEBUG(BB->dump());
if (!Fast)
PreprocessForRMW();
// FIXME: This should only happen when not -fast.
PreprocessForFPConvert();
// Codegen the basic block.
#ifndef NDEBUG
DOUT << "===== Instruction selection begins:\n";
Indent = 0;
#endif
SelectRoot(*CurDAG);
#ifndef NDEBUG
DOUT << "===== Instruction selection ends:\n";
#endif
CurDAG->RemoveDeadNodes();
}
/// EmitSpecialCodeForMain - Emit any code that needs to be executed only in
/// the main function.
void X86DAGToDAGISel::EmitSpecialCodeForMain(MachineBasicBlock *BB,
MachineFrameInfo *MFI) {
const TargetInstrInfo *TII = TM.getInstrInfo();
if (Subtarget->isTargetCygMing())
BuildMI(BB, TII->get(X86::CALLpcrel32)).addExternalSymbol("__main");
}
void X86DAGToDAGISel::EmitFunctionEntryCode(Function &Fn, MachineFunction &MF) {
// If this is main, emit special code for main.
MachineBasicBlock *BB = MF.begin();
if (Fn.hasExternalLinkage() && Fn.getName() == "main")
EmitSpecialCodeForMain(BB, MF.getFrameInfo());
}
/// MatchAddress - Add the specified node to the specified addressing mode,
/// returning true if it cannot be done. This just pattern matches for the
/// addressing mode.
bool X86DAGToDAGISel::MatchAddress(SDValue N, X86ISelAddressMode &AM,
bool isRoot, unsigned Depth) {
bool is64Bit = Subtarget->is64Bit();
DOUT << "MatchAddress: "; DEBUG(AM.dump());
// Limit recursion.
if (Depth > 5)
return MatchAddressBase(N, AM, isRoot, Depth);
// RIP relative addressing: %rip + 32-bit displacement!
if (AM.isRIPRel) {
if (!AM.ES && AM.JT != -1 && N.getOpcode() == ISD::Constant) {
uint64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
if (!is64Bit || isInt32(AM.Disp + Val)) {
AM.Disp += Val;
return false;
}
}
return true;
}
switch (N.getOpcode()) {
default: break;
case ISD::Constant: {
uint64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
if (!is64Bit || isInt32(AM.Disp + Val)) {
AM.Disp += Val;
return false;
}
break;
}
case X86ISD::Wrapper: {
DOUT << "Wrapper: 64bit " << is64Bit;
DOUT << " AM "; DEBUG(AM.dump()); DOUT << "\n";
// Under X86-64 non-small code model, GV (and friends) are 64-bits.
// Also, base and index reg must be 0 in order to use rip as base.
if (is64Bit && (TM.getCodeModel() != CodeModel::Small ||
AM.Base.Reg.getNode() || AM.IndexReg.getNode()))
break;
if (AM.GV != 0 || AM.CP != 0 || AM.ES != 0 || AM.JT != -1)
break;
// If value is available in a register both base and index components have
// been picked, we can't fit the result available in the register in the
// addressing mode. Duplicate GlobalAddress or ConstantPool as displacement.
{
SDValue N0 = N.getOperand(0);
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
uint64_t Offset = G->getOffset();
if (!is64Bit || isInt32(AM.Disp + Offset)) {
GlobalValue *GV = G->getGlobal();
AM.GV = GV;
AM.Disp += Offset;
AM.isRIPRel = TM.symbolicAddressesAreRIPRel();
return false;
}
} else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(N0)) {
uint64_t Offset = CP->getOffset();
if (!is64Bit || isInt32(AM.Disp + Offset)) {
AM.CP = CP->getConstVal();
AM.Align = CP->getAlignment();
AM.Disp += Offset;
AM.isRIPRel = TM.symbolicAddressesAreRIPRel();
return false;
}
} else if (ExternalSymbolSDNode *S =dyn_cast<ExternalSymbolSDNode>(N0)) {
AM.ES = S->getSymbol();
AM.isRIPRel = TM.symbolicAddressesAreRIPRel();
return false;
} else if (JumpTableSDNode *J = dyn_cast<JumpTableSDNode>(N0)) {
AM.JT = J->getIndex();
AM.isRIPRel = TM.symbolicAddressesAreRIPRel();
return false;
}
}
break;
}
case ISD::FrameIndex:
if (AM.BaseType == X86ISelAddressMode::RegBase
&& AM.Base.Reg.getNode() == 0) {
AM.BaseType = X86ISelAddressMode::FrameIndexBase;
AM.Base.FrameIndex = cast<FrameIndexSDNode>(N)->getIndex();
return false;
}
break;
case ISD::SHL:
if (AM.IndexReg.getNode() != 0 || AM.Scale != 1 || AM.isRIPRel)
break;
if (ConstantSDNode
*CN = dyn_cast<ConstantSDNode>(N.getNode()->getOperand(1))) {
unsigned Val = CN->getZExtValue();
if (Val == 1 || Val == 2 || Val == 3) {
AM.Scale = 1 << Val;
SDValue ShVal = N.getNode()->getOperand(0);
// Okay, we know that we have a scale by now. However, if the scaled
// value is an add of something and a constant, we can fold the
// constant into the disp field here.
if (ShVal.getNode()->getOpcode() == ISD::ADD && ShVal.hasOneUse() &&
isa<ConstantSDNode>(ShVal.getNode()->getOperand(1))) {
AM.IndexReg = ShVal.getNode()->getOperand(0);
ConstantSDNode *AddVal =
cast<ConstantSDNode>(ShVal.getNode()->getOperand(1));
uint64_t Disp = AM.Disp + (AddVal->getZExtValue() << Val);
if (!is64Bit || isInt32(Disp))
AM.Disp = Disp;
else
AM.IndexReg = ShVal;
} else {
AM.IndexReg = ShVal;
}
return false;
}
break;
}
case ISD::SMUL_LOHI:
case ISD::UMUL_LOHI:
// A mul_lohi where we need the low part can be folded as a plain multiply.
if (N.getResNo() != 0) break;
// FALL THROUGH
case ISD::MUL:
// X*[3,5,9] -> X+X*[2,4,8]
if (AM.BaseType == X86ISelAddressMode::RegBase &&
AM.Base.Reg.getNode() == 0 &&
AM.IndexReg.getNode() == 0 &&
!AM.isRIPRel) {
if (ConstantSDNode
*CN = dyn_cast<ConstantSDNode>(N.getNode()->getOperand(1)))
if (CN->getZExtValue() == 3 || CN->getZExtValue() == 5 ||
CN->getZExtValue() == 9) {
AM.Scale = unsigned(CN->getZExtValue())-1;
SDValue MulVal = N.getNode()->getOperand(0);
SDValue Reg;
// Okay, we know that we have a scale by now. However, if the scaled
// value is an add of something and a constant, we can fold the
// constant into the disp field here.
if (MulVal.getNode()->getOpcode() == ISD::ADD && MulVal.hasOneUse() &&
isa<ConstantSDNode>(MulVal.getNode()->getOperand(1))) {
Reg = MulVal.getNode()->getOperand(0);
ConstantSDNode *AddVal =
cast<ConstantSDNode>(MulVal.getNode()->getOperand(1));
uint64_t Disp = AM.Disp + AddVal->getZExtValue() *
CN->getZExtValue();
if (!is64Bit || isInt32(Disp))
AM.Disp = Disp;
else
Reg = N.getNode()->getOperand(0);
} else {
Reg = N.getNode()->getOperand(0);
}
AM.IndexReg = AM.Base.Reg = Reg;
return false;
}
}
break;
case ISD::ADD:
{
X86ISelAddressMode Backup = AM;
if (!MatchAddress(N.getNode()->getOperand(0), AM, false, Depth+1) &&
!MatchAddress(N.getNode()->getOperand(1), AM, false, Depth+1))
return false;
AM = Backup;
if (!MatchAddress(N.getNode()->getOperand(1), AM, false, Depth+1) &&
!MatchAddress(N.getNode()->getOperand(0), AM, false, Depth+1))
return false;
AM = Backup;
}
break;
case ISD::OR:
// Handle "X | C" as "X + C" iff X is known to have C bits clear.
if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
X86ISelAddressMode Backup = AM;
uint64_t Offset = CN->getSExtValue();
// Start with the LHS as an addr mode.
if (!MatchAddress(N.getOperand(0), AM, false) &&
// Address could not have picked a GV address for the displacement.
AM.GV == NULL &&
// On x86-64, the resultant disp must fit in 32-bits.
(!is64Bit || isInt32(AM.Disp + Offset)) &&
// Check to see if the LHS & C is zero.
CurDAG->MaskedValueIsZero(N.getOperand(0), CN->getAPIntValue())) {
AM.Disp += Offset;
return false;
}
AM = Backup;
}
break;
case ISD::AND: {
// Handle "(x << C1) & C2" as "(X & (C2>>C1)) << C1" if safe and if this
// allows us to fold the shift into this addressing mode.
SDValue Shift = N.getOperand(0);
if (Shift.getOpcode() != ISD::SHL) break;
// Scale must not be used already.
if (AM.IndexReg.getNode() != 0 || AM.Scale != 1) break;
// Not when RIP is used as the base.
if (AM.isRIPRel) break;
ConstantSDNode *C2 = dyn_cast<ConstantSDNode>(N.getOperand(1));
ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(Shift.getOperand(1));
if (!C1 || !C2) break;
// Not likely to be profitable if either the AND or SHIFT node has more
// than one use (unless all uses are for address computation). Besides,
// isel mechanism requires their node ids to be reused.
if (!N.hasOneUse() || !Shift.hasOneUse())
break;
// Verify that the shift amount is something we can fold.
unsigned ShiftCst = C1->getZExtValue();
if (ShiftCst != 1 && ShiftCst != 2 && ShiftCst != 3)
break;
// Get the new AND mask, this folds to a constant.
SDValue X = Shift.getOperand(0);
SDValue NewANDMask = CurDAG->getNode(ISD::SRL, N.getValueType(),
SDValue(C2, 0), SDValue(C1, 0));
SDValue NewAND = CurDAG->getNode(ISD::AND, N.getValueType(), X, NewANDMask);
SDValue NewSHIFT = CurDAG->getNode(ISD::SHL, N.getValueType(),
NewAND, SDValue(C1, 0));
// Insert the new nodes into the topological ordering.
if (C1->getNodeId() > X.getNode()->getNodeId()) {
CurDAG->RepositionNode(X.getNode(), C1);
C1->setNodeId(X.getNode()->getNodeId());
}
if (NewANDMask.getNode()->getNodeId() == -1 ||
NewANDMask.getNode()->getNodeId() > X.getNode()->getNodeId()) {
CurDAG->RepositionNode(X.getNode(), NewANDMask.getNode());
NewANDMask.getNode()->setNodeId(X.getNode()->getNodeId());
}
if (NewAND.getNode()->getNodeId() == -1 ||
NewAND.getNode()->getNodeId() > Shift.getNode()->getNodeId()) {
CurDAG->RepositionNode(Shift.getNode(), NewAND.getNode());
NewAND.getNode()->setNodeId(Shift.getNode()->getNodeId());
}
if (NewSHIFT.getNode()->getNodeId() == -1 ||
NewSHIFT.getNode()->getNodeId() > N.getNode()->getNodeId()) {
CurDAG->RepositionNode(N.getNode(), NewSHIFT.getNode());
NewSHIFT.getNode()->setNodeId(N.getNode()->getNodeId());
}
CurDAG->ReplaceAllUsesWith(N, NewSHIFT);
AM.Scale = 1 << ShiftCst;
AM.IndexReg = NewAND;
return false;
}
}
return MatchAddressBase(N, AM, isRoot, Depth);
}
/// MatchAddressBase - Helper for MatchAddress. Add the specified node to the
/// specified addressing mode without any further recursion.
bool X86DAGToDAGISel::MatchAddressBase(SDValue N, X86ISelAddressMode &AM,
bool isRoot, unsigned Depth) {
// Is the base register already occupied?
if (AM.BaseType != X86ISelAddressMode::RegBase || AM.Base.Reg.getNode()) {
// If so, check to see if the scale index register is set.
if (AM.IndexReg.getNode() == 0 && !AM.isRIPRel) {
AM.IndexReg = N;
AM.Scale = 1;
return false;
}
// Otherwise, we cannot select it.
return true;
}
// Default, generate it as a register.
AM.BaseType = X86ISelAddressMode::RegBase;
AM.Base.Reg = N;
return false;
}
/// SelectAddr - returns true if it is able pattern match an addressing mode.
/// It returns the operands which make up the maximal addressing mode it can
/// match by reference.
bool X86DAGToDAGISel::SelectAddr(SDValue Op, SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index,
SDValue &Disp) {
X86ISelAddressMode AM;
if (MatchAddress(N, AM))
return false;
MVT VT = N.getValueType();
if (AM.BaseType == X86ISelAddressMode::RegBase) {
if (!AM.Base.Reg.getNode())
AM.Base.Reg = CurDAG->getRegister(0, VT);
}
if (!AM.IndexReg.getNode())
AM.IndexReg = CurDAG->getRegister(0, VT);
getAddressOperands(AM, Base, Scale, Index, Disp);
return true;
}
/// SelectScalarSSELoad - Match a scalar SSE load. In particular, we want to
/// match a load whose top elements are either undef or zeros. The load flavor
/// is derived from the type of N, which is either v4f32 or v2f64.
bool X86DAGToDAGISel::SelectScalarSSELoad(SDValue Op, SDValue Pred,
SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index,
SDValue &Disp, SDValue &InChain,
SDValue &OutChain) {
if (N.getOpcode() == ISD::SCALAR_TO_VECTOR) {
InChain = N.getOperand(0).getValue(1);
if (ISD::isNON_EXTLoad(InChain.getNode()) &&
InChain.getValue(0).hasOneUse() &&
N.hasOneUse() &&
IsLegalAndProfitableToFold(N.getNode(), Pred.getNode(), Op.getNode())) {
LoadSDNode *LD = cast<LoadSDNode>(InChain);
if (!SelectAddr(Op, LD->getBasePtr(), Base, Scale, Index, Disp))
return false;
OutChain = LD->getChain();
return true;
}
}
// Also handle the case where we explicitly require zeros in the top
// elements. This is a vector shuffle from the zero vector.
if (N.getOpcode() == X86ISD::VZEXT_MOVL && N.getNode()->hasOneUse() &&
// Check to see if the top elements are all zeros (or bitcast of zeros).
N.getOperand(0).getOpcode() == ISD::SCALAR_TO_VECTOR &&
N.getOperand(0).getNode()->hasOneUse() &&
ISD::isNON_EXTLoad(N.getOperand(0).getOperand(0).getNode()) &&
N.getOperand(0).getOperand(0).hasOneUse()) {
// Okay, this is a zero extending load. Fold it.
LoadSDNode *LD = cast<LoadSDNode>(N.getOperand(0).getOperand(0));
if (!SelectAddr(Op, LD->getBasePtr(), Base, Scale, Index, Disp))
return false;
OutChain = LD->getChain();
InChain = SDValue(LD, 1);
return true;
}
return false;
}
/// SelectLEAAddr - it calls SelectAddr and determines if the maximal addressing
/// mode it matches can be cost effectively emitted as an LEA instruction.
bool X86DAGToDAGISel::SelectLEAAddr(SDValue Op, SDValue N,
SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp) {
X86ISelAddressMode AM;
if (MatchAddress(N, AM))
return false;
MVT VT = N.getValueType();
unsigned Complexity = 0;
if (AM.BaseType == X86ISelAddressMode::RegBase)
if (AM.Base.Reg.getNode())
Complexity = 1;
else
AM.Base.Reg = CurDAG->getRegister(0, VT);
else if (AM.BaseType == X86ISelAddressMode::FrameIndexBase)
Complexity = 4;
if (AM.IndexReg.getNode())
Complexity++;
else
AM.IndexReg = CurDAG->getRegister(0, VT);
// Don't match just leal(,%reg,2). It's cheaper to do addl %reg, %reg, or with
// a simple shift.
if (AM.Scale > 1)
Complexity++;
// FIXME: We are artificially lowering the criteria to turn ADD %reg, $GA
// to a LEA. This is determined with some expermentation but is by no means
// optimal (especially for code size consideration). LEA is nice because of
// its three-address nature. Tweak the cost function again when we can run
// convertToThreeAddress() at register allocation time.
if (AM.GV || AM.CP || AM.ES || AM.JT != -1) {
// For X86-64, we should always use lea to materialize RIP relative
// addresses.
if (Subtarget->is64Bit())
Complexity = 4;
else
Complexity += 2;
}
if (AM.Disp && (AM.Base.Reg.getNode() || AM.IndexReg.getNode()))
Complexity++;
if (Complexity > 2) {
getAddressOperands(AM, Base, Scale, Index, Disp);
return true;
}
return false;
}
bool X86DAGToDAGISel::TryFoldLoad(SDValue P, SDValue N,
SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp) {
if (ISD::isNON_EXTLoad(N.getNode()) &&
N.hasOneUse() &&
IsLegalAndProfitableToFold(N.getNode(), P.getNode(), P.getNode()))
return SelectAddr(P, N.getOperand(1), Base, Scale, Index, Disp);
return false;
}
/// getGlobalBaseReg - Return an SDNode that returns the value of
/// the global base register. Output instructions required to
/// initialize the global base register, if necessary.
///
SDNode *X86DAGToDAGISel::getGlobalBaseReg() {
MachineFunction *MF = CurBB->getParent();
unsigned GlobalBaseReg = TM.getInstrInfo()->getGlobalBaseReg(MF);
return CurDAG->getRegister(GlobalBaseReg, TLI.getPointerTy()).getNode();
}
static SDNode *FindCallStartFromCall(SDNode *Node) {
if (Node->getOpcode() == ISD::CALLSEQ_START) return Node;
assert(Node->getOperand(0).getValueType() == MVT::Other &&
"Node doesn't have a token chain argument!");
return FindCallStartFromCall(Node->getOperand(0).getNode());
}
/// getTruncateTo8Bit - return an SDNode that implements a subreg based
/// truncate of the specified operand to i8. This can be done with tablegen,
/// except that this code uses MVT::Flag in a tricky way that happens to
/// improve scheduling in some cases.
SDNode *X86DAGToDAGISel::getTruncateTo8Bit(SDValue N0) {
assert(!Subtarget->is64Bit() &&
"getTruncateTo8Bit is only needed on x86-32!");
SDValue SRIdx = CurDAG->getTargetConstant(1, MVT::i32); // SubRegSet 1
// Ensure that the source register has an 8-bit subreg on 32-bit targets
unsigned Opc;
MVT N0VT = N0.getValueType();
switch (N0VT.getSimpleVT()) {
default: assert(0 && "Unknown truncate!");
case MVT::i16:
Opc = X86::MOV16to16_;
break;
case MVT::i32:
Opc = X86::MOV32to32_;
break;
}
// The use of MVT::Flag here is not strictly accurate, but it helps
// scheduling in some cases.
N0 = SDValue(CurDAG->getTargetNode(Opc, N0VT, MVT::Flag, N0), 0);
return CurDAG->getTargetNode(X86::EXTRACT_SUBREG,
MVT::i8, N0, SRIdx, N0.getValue(1));
}
SDNode *X86DAGToDAGISel::SelectAtomic64(SDNode *Node, unsigned Opc) {
SDValue Chain = Node->getOperand(0);
SDValue In1 = Node->getOperand(1);
SDValue In2L = Node->getOperand(2);
SDValue In2H = Node->getOperand(3);
SDValue Tmp0, Tmp1, Tmp2, Tmp3;
if (!SelectAddr(In1, In1, Tmp0, Tmp1, Tmp2, Tmp3))
return NULL;
SDValue LSI = Node->getOperand(4); // MemOperand
const SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, In2L, In2H, LSI, Chain };
return CurDAG->getTargetNode(Opc, MVT::i32, MVT::i32, MVT::Other, Ops, 8);
}
SDNode *X86DAGToDAGISel::Select(SDValue N) {
SDNode *Node = N.getNode();
MVT NVT = Node->getValueType(0);
unsigned Opc, MOpc;
unsigned Opcode = Node->getOpcode();
#ifndef NDEBUG
DOUT << std::string(Indent, ' ') << "Selecting: ";
DEBUG(Node->dump(CurDAG));
DOUT << "\n";
Indent += 2;
#endif
if (Node->isMachineOpcode()) {
#ifndef NDEBUG
DOUT << std::string(Indent-2, ' ') << "== ";
DEBUG(Node->dump(CurDAG));
DOUT << "\n";
Indent -= 2;
#endif
return NULL; // Already selected.
}
switch (Opcode) {
default: break;
case X86ISD::GlobalBaseReg:
return getGlobalBaseReg();
case X86ISD::ATOMOR64_DAG:
return SelectAtomic64(Node, X86::ATOMOR6432);
case X86ISD::ATOMXOR64_DAG:
return SelectAtomic64(Node, X86::ATOMXOR6432);
case X86ISD::ATOMADD64_DAG:
return SelectAtomic64(Node, X86::ATOMADD6432);
case X86ISD::ATOMSUB64_DAG:
return SelectAtomic64(Node, X86::ATOMSUB6432);
case X86ISD::ATOMNAND64_DAG:
return SelectAtomic64(Node, X86::ATOMNAND6432);
case X86ISD::ATOMAND64_DAG:
return SelectAtomic64(Node, X86::ATOMAND6432);
case X86ISD::ATOMSWAP64_DAG:
return SelectAtomic64(Node, X86::ATOMSWAP6432);
case ISD::SMUL_LOHI:
case ISD::UMUL_LOHI: {
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
bool isSigned = Opcode == ISD::SMUL_LOHI;
if (!isSigned)
switch (NVT.getSimpleVT()) {
default: assert(0 && "Unsupported VT!");
case MVT::i8: Opc = X86::MUL8r; MOpc = X86::MUL8m; break;
case MVT::i16: Opc = X86::MUL16r; MOpc = X86::MUL16m; break;
case MVT::i32: Opc = X86::MUL32r; MOpc = X86::MUL32m; break;
case MVT::i64: Opc = X86::MUL64r; MOpc = X86::MUL64m; break;
}
else
switch (NVT.getSimpleVT()) {
default: assert(0 && "Unsupported VT!");
case MVT::i8: Opc = X86::IMUL8r; MOpc = X86::IMUL8m; break;
case MVT::i16: Opc = X86::IMUL16r; MOpc = X86::IMUL16m; break;
case MVT::i32: Opc = X86::IMUL32r; MOpc = X86::IMUL32m; break;
case MVT::i64: Opc = X86::IMUL64r; MOpc = X86::IMUL64m; break;
}
unsigned LoReg, HiReg;
switch (NVT.getSimpleVT()) {
default: assert(0 && "Unsupported VT!");
case MVT::i8: LoReg = X86::AL; HiReg = X86::AH; break;
case MVT::i16: LoReg = X86::AX; HiReg = X86::DX; break;
case MVT::i32: LoReg = X86::EAX; HiReg = X86::EDX; break;
case MVT::i64: LoReg = X86::RAX; HiReg = X86::RDX; break;
}
SDValue Tmp0, Tmp1, Tmp2, Tmp3;
bool foldedLoad = TryFoldLoad(N, N1, Tmp0, Tmp1, Tmp2, Tmp3);
// multiplty is commmutative
if (!foldedLoad) {
foldedLoad = TryFoldLoad(N, N0, Tmp0, Tmp1, Tmp2, Tmp3);
if (foldedLoad)
std::swap(N0, N1);
}
SDValue InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), LoReg,
N0, SDValue()).getValue(1);
if (foldedLoad) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, N1.getOperand(0), InFlag };
SDNode *CNode =
CurDAG->getTargetNode(MOpc, MVT::Other, MVT::Flag, Ops, 6);
InFlag = SDValue(CNode, 1);
// Update the chain.
ReplaceUses(N1.getValue(1), SDValue(CNode, 0));
} else {
InFlag =
SDValue(CurDAG->getTargetNode(Opc, MVT::Flag, N1, InFlag), 0);
}
// Copy the low half of the result, if it is needed.
if (!N.getValue(0).use_empty()) {
SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(),
LoReg, NVT, InFlag);
InFlag = Result.getValue(2);
ReplaceUses(N.getValue(0), Result);
#ifndef NDEBUG
DOUT << std::string(Indent-2, ' ') << "=> ";
DEBUG(Result.getNode()->dump(CurDAG));
DOUT << "\n";
#endif
}
// Copy the high half of the result, if it is needed.
if (!N.getValue(1).use_empty()) {
SDValue Result;
if (HiReg == X86::AH && Subtarget->is64Bit()) {
// Prevent use of AH in a REX instruction by referencing AX instead.
// Shift it down 8 bits.
Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(),
X86::AX, MVT::i16, InFlag);
InFlag = Result.getValue(2);
Result = SDValue(CurDAG->getTargetNode(X86::SHR16ri, MVT::i16, Result,
CurDAG->getTargetConstant(8, MVT::i8)), 0);
// Then truncate it down to i8.
SDValue SRIdx = CurDAG->getTargetConstant(1, MVT::i32); // SubRegSet 1
Result = SDValue(CurDAG->getTargetNode(X86::EXTRACT_SUBREG,
MVT::i8, Result, SRIdx), 0);
} else {
Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(),
HiReg, NVT, InFlag);
InFlag = Result.getValue(2);
}
ReplaceUses(N.getValue(1), Result);
#ifndef NDEBUG
DOUT << std::string(Indent-2, ' ') << "=> ";
DEBUG(Result.getNode()->dump(CurDAG));
DOUT << "\n";
#endif
}
#ifndef NDEBUG
Indent -= 2;
#endif
return NULL;
}
case ISD::SDIVREM:
case ISD::UDIVREM: {
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
bool isSigned = Opcode == ISD::SDIVREM;
if (!isSigned)
switch (NVT.getSimpleVT()) {
default: assert(0 && "Unsupported VT!");
case MVT::i8: Opc = X86::DIV8r; MOpc = X86::DIV8m; break;
case MVT::i16: Opc = X86::DIV16r; MOpc = X86::DIV16m; break;
case MVT::i32: Opc = X86::DIV32r; MOpc = X86::DIV32m; break;
case MVT::i64: Opc = X86::DIV64r; MOpc = X86::DIV64m; break;
}
else
switch (NVT.getSimpleVT()) {
default: assert(0 && "Unsupported VT!");
case MVT::i8: Opc = X86::IDIV8r; MOpc = X86::IDIV8m; break;
case MVT::i16: Opc = X86::IDIV16r; MOpc = X86::IDIV16m; break;
case MVT::i32: Opc = X86::IDIV32r; MOpc = X86::IDIV32m; break;
case MVT::i64: Opc = X86::IDIV64r; MOpc = X86::IDIV64m; break;
}
unsigned LoReg, HiReg;
unsigned ClrOpcode, SExtOpcode;
switch (NVT.getSimpleVT()) {
default: assert(0 && "Unsupported VT!");
case MVT::i8:
LoReg = X86::AL; HiReg = X86::AH;
ClrOpcode = 0;
SExtOpcode = X86::CBW;
break;
case MVT::i16:
LoReg = X86::AX; HiReg = X86::DX;
ClrOpcode = X86::MOV16r0;
SExtOpcode = X86::CWD;
break;
case MVT::i32:
LoReg = X86::EAX; HiReg = X86::EDX;
ClrOpcode = X86::MOV32r0;
SExtOpcode = X86::CDQ;
break;
case MVT::i64:
LoReg = X86::RAX; HiReg = X86::RDX;
ClrOpcode = X86::MOV64r0;
SExtOpcode = X86::CQO;
break;
}
SDValue Tmp0, Tmp1, Tmp2, Tmp3;
bool foldedLoad = TryFoldLoad(N, N1, Tmp0, Tmp1, Tmp2, Tmp3);
SDValue InFlag;
if (NVT == MVT::i8 && !isSigned) {
// Special case for div8, just use a move with zero extension to AX to
// clear the upper 8 bits (AH).
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Move, Chain;
if (TryFoldLoad(N, N0, Tmp0, Tmp1, Tmp2, Tmp3)) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, N0.getOperand(0) };
Move =
SDValue(CurDAG->getTargetNode(X86::MOVZX16rm8, MVT::i16, MVT::Other,
Ops, 5), 0);
Chain = Move.getValue(1);
ReplaceUses(N0.getValue(1), Chain);
} else {
Move =
SDValue(CurDAG->getTargetNode(X86::MOVZX16rr8, MVT::i16, N0), 0);
Chain = CurDAG->getEntryNode();
}
Chain = CurDAG->getCopyToReg(Chain, X86::AX, Move, SDValue());
InFlag = Chain.getValue(1);
} else {
InFlag =
CurDAG->getCopyToReg(CurDAG->getEntryNode(),
LoReg, N0, SDValue()).getValue(1);
if (isSigned) {
// Sign extend the low part into the high part.
InFlag =
SDValue(CurDAG->getTargetNode(SExtOpcode, MVT::Flag, InFlag), 0);
} else {
// Zero out the high part, effectively zero extending the input.
SDValue ClrNode = SDValue(CurDAG->getTargetNode(ClrOpcode, NVT), 0);
InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), HiReg,
ClrNode, InFlag).getValue(1);
}
}
if (foldedLoad) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, N1.getOperand(0), InFlag };
SDNode *CNode =
CurDAG->getTargetNode(MOpc, MVT::Other, MVT::Flag, Ops, 6);
InFlag = SDValue(CNode, 1);
// Update the chain.
ReplaceUses(N1.getValue(1), SDValue(CNode, 0));
} else {
InFlag =
SDValue(CurDAG->getTargetNode(Opc, MVT::Flag, N1, InFlag), 0);
}
// Copy the division (low) result, if it is needed.
if (!N.getValue(0).use_empty()) {
SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(),
LoReg, NVT, InFlag);
InFlag = Result.getValue(2);
ReplaceUses(N.getValue(0), Result);
#ifndef NDEBUG
DOUT << std::string(Indent-2, ' ') << "=> ";
DEBUG(Result.getNode()->dump(CurDAG));
DOUT << "\n";
#endif
}
// Copy the remainder (high) result, if it is needed.
if (!N.getValue(1).use_empty()) {
SDValue Result;
if (HiReg == X86::AH && Subtarget->is64Bit()) {
// Prevent use of AH in a REX instruction by referencing AX instead.
// Shift it down 8 bits.
Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(),
X86::AX, MVT::i16, InFlag);
InFlag = Result.getValue(2);
Result = SDValue(CurDAG->getTargetNode(X86::SHR16ri, MVT::i16, Result,
CurDAG->getTargetConstant(8, MVT::i8)), 0);
// Then truncate it down to i8.
SDValue SRIdx = CurDAG->getTargetConstant(1, MVT::i32); // SubRegSet 1
Result = SDValue(CurDAG->getTargetNode(X86::EXTRACT_SUBREG,
MVT::i8, Result, SRIdx), 0);
} else {
Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(),
HiReg, NVT, InFlag);
InFlag = Result.getValue(2);
}
ReplaceUses(N.getValue(1), Result);
#ifndef NDEBUG
DOUT << std::string(Indent-2, ' ') << "=> ";
DEBUG(Result.getNode()->dump(CurDAG));
DOUT << "\n";
#endif
}
#ifndef NDEBUG
Indent -= 2;
#endif
return NULL;
}
case ISD::SIGN_EXTEND_INREG: {
MVT SVT = cast<VTSDNode>(Node->getOperand(1))->getVT();
if (SVT == MVT::i8 && !Subtarget->is64Bit()) {
SDValue N0 = Node->getOperand(0);
SDValue TruncOp = SDValue(getTruncateTo8Bit(N0), 0);
unsigned Opc = 0;
switch (NVT.getSimpleVT()) {
default: assert(0 && "Unknown sign_extend_inreg!");
case MVT::i16:
Opc = X86::MOVSX16rr8;
break;
case MVT::i32:
Opc = X86::MOVSX32rr8;
break;
}
SDNode *ResNode = CurDAG->getTargetNode(Opc, NVT, TruncOp);
#ifndef NDEBUG
DOUT << std::string(Indent-2, ' ') << "=> ";
DEBUG(TruncOp.getNode()->dump(CurDAG));
DOUT << "\n";
DOUT << std::string(Indent-2, ' ') << "=> ";
DEBUG(ResNode->dump(CurDAG));
DOUT << "\n";
Indent -= 2;
#endif
return ResNode;
}
break;
}
case ISD::TRUNCATE: {
if (NVT == MVT::i8 && !Subtarget->is64Bit()) {
SDValue Input = Node->getOperand(0);
SDNode *ResNode = getTruncateTo8Bit(Input);
#ifndef NDEBUG
DOUT << std::string(Indent-2, ' ') << "=> ";
DEBUG(ResNode->dump(CurDAG));
DOUT << "\n";
Indent -= 2;
#endif
return ResNode;
}
break;
}
case ISD::DECLARE: {
// Handle DECLARE nodes here because the second operand may have been
// wrapped in X86ISD::Wrapper.
SDValue Chain = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
SDValue N2 = Node->getOperand(2);
if (!isa<FrameIndexSDNode>(N1))
break;
int FI = cast<FrameIndexSDNode>(N1)->getIndex();
if (N2.getOpcode() == ISD::ADD &&
N2.getOperand(0).getOpcode() == X86ISD::GlobalBaseReg)
N2 = N2.getOperand(1);
if (N2.getOpcode() == X86ISD::Wrapper &&
isa<GlobalAddressSDNode>(N2.getOperand(0))) {
GlobalValue *GV =
cast<GlobalAddressSDNode>(N2.getOperand(0))->getGlobal();
SDValue Tmp1 = CurDAG->getTargetFrameIndex(FI, TLI.getPointerTy());
SDValue Tmp2 = CurDAG->getTargetGlobalAddress(GV, TLI.getPointerTy());
SDValue Ops[] = { Tmp1, Tmp2, Chain };
return CurDAG->getTargetNode(TargetInstrInfo::DECLARE,
MVT::Other, Ops, 3);
}
break;
}
}
SDNode *ResNode = SelectCode(N);
#ifndef NDEBUG
DOUT << std::string(Indent-2, ' ') << "=> ";
if (ResNode == NULL || ResNode == N.getNode())
DEBUG(N.getNode()->dump(CurDAG));
else
DEBUG(ResNode->dump(CurDAG));
DOUT << "\n";
Indent -= 2;
#endif
return ResNode;
}
bool X86DAGToDAGISel::
SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode,
std::vector<SDValue> &OutOps) {
SDValue Op0, Op1, Op2, Op3;
switch (ConstraintCode) {
case 'o': // offsetable ??
case 'v': // not offsetable ??
default: return true;
case 'm': // memory
if (!SelectAddr(Op, Op, Op0, Op1, Op2, Op3))
return true;
break;
}
OutOps.push_back(Op0);
OutOps.push_back(Op1);
OutOps.push_back(Op2);
OutOps.push_back(Op3);
return false;
}
/// createX86ISelDag - This pass converts a legalized DAG into a
/// X86-specific DAG, ready for instruction scheduling.
///
FunctionPass *llvm::createX86ISelDag(X86TargetMachine &TM, bool Fast) {
return new X86DAGToDAGISel(TM, Fast);
}
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