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llvm-6502/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
Andrew Trick 47c144505b misched preparation: clarify ScheduleDAG and ScheduleDAGInstrs roles. 
ScheduleDAG is responsible for the DAG: SUnits and SDeps. It provides target hooks for latency computation.

ScheduleDAGInstrs extends ScheduleDAG and defines the current scheduling region in terms of MachineInstr iterators. It has access to the target's scheduling itinerary data. ScheduleDAGInstrs provides the logic for building the ScheduleDAG for the sequence of MachineInstrs in the current region. Target's can implement highly custom schedulers by extending this class.

ScheduleDAGPostRATDList provides the driver and diagnostics for current postRA scheduling. It maintains a current Sequence of scheduled machine instructions and logic for splicing them into the block. During scheduling, it uses the ScheduleHazardRecognizer provided by the target.

Specific changes:
- Removed driver code from ScheduleDAG. clearDAG is the only interface needed.

- Added enterRegion/exitRegion hooks to ScheduleDAGInstrs to delimit the scope of each scheduling region and associated DAG. They should be used to setup and cleanup any region-specific state in addition to the DAG itself. This is necessary because we reuse the same ScheduleDAG object for the entire function. The target may extend these hooks to do things at regions boundaries, like bundle terminators. The hooks are called even if we decide not to schedule the region. So all instructions in a block are "covered" by these calls.

- Added ScheduleDAGInstrs::begin()/end() public API.

- Moved Sequence into the driver layer, which is specific to the scheduling algorithm.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152208 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-07 05:21:52 +00:00

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//===-- SelectionDAGISel.cpp - Implement the SelectionDAGISel class -------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This implements the SelectionDAGISel class.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "isel"
#include "ScheduleDAGSDNodes.h"
#include "SelectionDAGBuilder.h"
#include "llvm/CodeGen/FunctionLoweringInfo.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/Analysis/DebugInfo.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/InlineAsm.h"
#include "llvm/Instructions.h"
#include "llvm/Intrinsics.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/CodeGen/FastISel.h"
#include "llvm/CodeGen/GCStrategy.h"
#include "llvm/CodeGen/GCMetadata.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
#include "llvm/CodeGen/SchedulerRegistry.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetIntrinsicInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Timer.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/Statistic.h"
#include <algorithm>
using namespace llvm;
STATISTIC(NumFastIselFailures, "Number of instructions fast isel failed on");
STATISTIC(NumFastIselSuccess, "Number of instructions fast isel selected");
STATISTIC(NumFastIselBlocks, "Number of blocks selected entirely by fast isel");
STATISTIC(NumDAGBlocks, "Number of blocks selected using DAG");
STATISTIC(NumDAGIselRetries,"Number of times dag isel has to try another path");
#ifndef NDEBUG
static cl::opt<bool>
EnableFastISelVerbose2("fast-isel-verbose2", cl::Hidden,
cl::desc("Enable extra verbose messages in the \"fast\" "
"instruction selector"));
// Terminators
STATISTIC(NumFastIselFailRet,"Fast isel fails on Ret");
STATISTIC(NumFastIselFailBr,"Fast isel fails on Br");
STATISTIC(NumFastIselFailSwitch,"Fast isel fails on Switch");
STATISTIC(NumFastIselFailIndirectBr,"Fast isel fails on IndirectBr");
STATISTIC(NumFastIselFailInvoke,"Fast isel fails on Invoke");
STATISTIC(NumFastIselFailResume,"Fast isel fails on Resume");
STATISTIC(NumFastIselFailUnreachable,"Fast isel fails on Unreachable");
// Standard binary operators...
STATISTIC(NumFastIselFailAdd,"Fast isel fails on Add");
STATISTIC(NumFastIselFailFAdd,"Fast isel fails on FAdd");
STATISTIC(NumFastIselFailSub,"Fast isel fails on Sub");
STATISTIC(NumFastIselFailFSub,"Fast isel fails on FSub");
STATISTIC(NumFastIselFailMul,"Fast isel fails on Mul");
STATISTIC(NumFastIselFailFMul,"Fast isel fails on FMul");
STATISTIC(NumFastIselFailUDiv,"Fast isel fails on UDiv");
STATISTIC(NumFastIselFailSDiv,"Fast isel fails on SDiv");
STATISTIC(NumFastIselFailFDiv,"Fast isel fails on FDiv");
STATISTIC(NumFastIselFailURem,"Fast isel fails on URem");
STATISTIC(NumFastIselFailSRem,"Fast isel fails on SRem");
STATISTIC(NumFastIselFailFRem,"Fast isel fails on FRem");
// Logical operators...
STATISTIC(NumFastIselFailAnd,"Fast isel fails on And");
STATISTIC(NumFastIselFailOr,"Fast isel fails on Or");
STATISTIC(NumFastIselFailXor,"Fast isel fails on Xor");
// Memory instructions...
STATISTIC(NumFastIselFailAlloca,"Fast isel fails on Alloca");
STATISTIC(NumFastIselFailLoad,"Fast isel fails on Load");
STATISTIC(NumFastIselFailStore,"Fast isel fails on Store");
STATISTIC(NumFastIselFailAtomicCmpXchg,"Fast isel fails on AtomicCmpXchg");
STATISTIC(NumFastIselFailAtomicRMW,"Fast isel fails on AtomicRWM");
STATISTIC(NumFastIselFailFence,"Fast isel fails on Frence");
STATISTIC(NumFastIselFailGetElementPtr,"Fast isel fails on GetElementPtr");
// Convert instructions...
STATISTIC(NumFastIselFailTrunc,"Fast isel fails on Trunc");
STATISTIC(NumFastIselFailZExt,"Fast isel fails on ZExt");
STATISTIC(NumFastIselFailSExt,"Fast isel fails on SExt");
STATISTIC(NumFastIselFailFPTrunc,"Fast isel fails on FPTrunc");
STATISTIC(NumFastIselFailFPExt,"Fast isel fails on FPExt");
STATISTIC(NumFastIselFailFPToUI,"Fast isel fails on FPToUI");
STATISTIC(NumFastIselFailFPToSI,"Fast isel fails on FPToSI");
STATISTIC(NumFastIselFailUIToFP,"Fast isel fails on UIToFP");
STATISTIC(NumFastIselFailSIToFP,"Fast isel fails on SIToFP");
STATISTIC(NumFastIselFailIntToPtr,"Fast isel fails on IntToPtr");
STATISTIC(NumFastIselFailPtrToInt,"Fast isel fails on PtrToInt");
STATISTIC(NumFastIselFailBitCast,"Fast isel fails on BitCast");
// Other instructions...
STATISTIC(NumFastIselFailICmp,"Fast isel fails on ICmp");
STATISTIC(NumFastIselFailFCmp,"Fast isel fails on FCmp");
STATISTIC(NumFastIselFailPHI,"Fast isel fails on PHI");
STATISTIC(NumFastIselFailSelect,"Fast isel fails on Select");
STATISTIC(NumFastIselFailCall,"Fast isel fails on Call");
STATISTIC(NumFastIselFailShl,"Fast isel fails on Shl");
STATISTIC(NumFastIselFailLShr,"Fast isel fails on LShr");
STATISTIC(NumFastIselFailAShr,"Fast isel fails on AShr");
STATISTIC(NumFastIselFailVAArg,"Fast isel fails on VAArg");
STATISTIC(NumFastIselFailExtractElement,"Fast isel fails on ExtractElement");
STATISTIC(NumFastIselFailInsertElement,"Fast isel fails on InsertElement");
STATISTIC(NumFastIselFailShuffleVector,"Fast isel fails on ShuffleVector");
STATISTIC(NumFastIselFailExtractValue,"Fast isel fails on ExtractValue");
STATISTIC(NumFastIselFailInsertValue,"Fast isel fails on InsertValue");
STATISTIC(NumFastIselFailLandingPad,"Fast isel fails on LandingPad");
#endif
static cl::opt<bool>
EnableFastISelVerbose("fast-isel-verbose", cl::Hidden,
cl::desc("Enable verbose messages in the \"fast\" "
"instruction selector"));
static cl::opt<bool>
EnableFastISelAbort("fast-isel-abort", cl::Hidden,
cl::desc("Enable abort calls when \"fast\" instruction fails"));
static cl::opt<bool>
UseMBPI("use-mbpi",
cl::desc("use Machine Branch Probability Info"),
cl::init(true), cl::Hidden);
#ifndef NDEBUG
static cl::opt<bool>
ViewDAGCombine1("view-dag-combine1-dags", cl::Hidden,
cl::desc("Pop up a window to show dags before the first "
"dag combine pass"));
static cl::opt<bool>
ViewLegalizeTypesDAGs("view-legalize-types-dags", cl::Hidden,
cl::desc("Pop up a window to show dags before legalize types"));
static cl::opt<bool>
ViewLegalizeDAGs("view-legalize-dags", cl::Hidden,
cl::desc("Pop up a window to show dags before legalize"));
static cl::opt<bool>
ViewDAGCombine2("view-dag-combine2-dags", cl::Hidden,
cl::desc("Pop up a window to show dags before the second "
"dag combine pass"));
static cl::opt<bool>
ViewDAGCombineLT("view-dag-combine-lt-dags", cl::Hidden,
cl::desc("Pop up a window to show dags before the post legalize types"
" dag combine pass"));
static cl::opt<bool>
ViewISelDAGs("view-isel-dags", cl::Hidden,
cl::desc("Pop up a window to show isel dags as they are selected"));
static cl::opt<bool>
ViewSchedDAGs("view-sched-dags", cl::Hidden,
cl::desc("Pop up a window to show sched dags as they are processed"));
static cl::opt<bool>
ViewSUnitDAGs("view-sunit-dags", cl::Hidden,
cl::desc("Pop up a window to show SUnit dags after they are processed"));
#else
static const bool ViewDAGCombine1 = false,
ViewLegalizeTypesDAGs = false, ViewLegalizeDAGs = false,
ViewDAGCombine2 = false,
ViewDAGCombineLT = false,
ViewISelDAGs = false, ViewSchedDAGs = false,
ViewSUnitDAGs = false;
#endif
//===---------------------------------------------------------------------===//
///
/// RegisterScheduler class - Track the registration of instruction schedulers.
///
//===---------------------------------------------------------------------===//
MachinePassRegistry RegisterScheduler::Registry;
//===---------------------------------------------------------------------===//
///
/// ISHeuristic command line option for instruction schedulers.
///
//===---------------------------------------------------------------------===//
static cl::opt<RegisterScheduler::FunctionPassCtor, false,
RegisterPassParser<RegisterScheduler> >
ISHeuristic("pre-RA-sched",
cl::init(&createDefaultScheduler),
cl::desc("Instruction schedulers available (before register"
" allocation):"));
static RegisterScheduler
defaultListDAGScheduler("default", "Best scheduler for the target",
createDefaultScheduler);
namespace llvm {
//===--------------------------------------------------------------------===//
/// createDefaultScheduler - This creates an instruction scheduler appropriate
/// for the target.
ScheduleDAGSDNodes* createDefaultScheduler(SelectionDAGISel *IS,
CodeGenOpt::Level OptLevel) {
const TargetLowering &TLI = IS->getTargetLowering();
if (OptLevel == CodeGenOpt::None ||
TLI.getSchedulingPreference() == Sched::Source)
return createSourceListDAGScheduler(IS, OptLevel);
if (TLI.getSchedulingPreference() == Sched::RegPressure)
return createBURRListDAGScheduler(IS, OptLevel);
if (TLI.getSchedulingPreference() == Sched::Hybrid)
return createHybridListDAGScheduler(IS, OptLevel);
if (TLI.getSchedulingPreference() == Sched::VLIW)
return createVLIWDAGScheduler(IS, OptLevel);
assert(TLI.getSchedulingPreference() == Sched::ILP &&
"Unknown sched type!");
return createILPListDAGScheduler(IS, OptLevel);
}
}
// EmitInstrWithCustomInserter - This method should be implemented by targets
// that mark instructions with the 'usesCustomInserter' flag. These
// instructions are special in various ways, which require special support to
// insert. The specified MachineInstr is created but not inserted into any
// basic blocks, and this method is called to expand it into a sequence of
// instructions, potentially also creating new basic blocks and control flow.
// When new basic blocks are inserted and the edges from MBB to its successors
// are modified, the method should insert pairs of <OldSucc, NewSucc> into the
// DenseMap.
MachineBasicBlock *
TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
MachineBasicBlock *MBB) const {
#ifndef NDEBUG
dbgs() << "If a target marks an instruction with "
"'usesCustomInserter', it must implement "
"TargetLowering::EmitInstrWithCustomInserter!";
#endif
llvm_unreachable(0);
}
void TargetLowering::AdjustInstrPostInstrSelection(MachineInstr *MI,
SDNode *Node) const {
assert(!MI->hasPostISelHook() &&
"If a target marks an instruction with 'hasPostISelHook', "
"it must implement TargetLowering::AdjustInstrPostInstrSelection!");
}
//===----------------------------------------------------------------------===//
// SelectionDAGISel code
//===----------------------------------------------------------------------===//
void SelectionDAGISel::ISelUpdater::anchor() { }
SelectionDAGISel::SelectionDAGISel(const TargetMachine &tm,
CodeGenOpt::Level OL) :
MachineFunctionPass(ID), TM(tm), TLI(*tm.getTargetLowering()),
FuncInfo(new FunctionLoweringInfo(TLI)),
CurDAG(new SelectionDAG(tm, OL)),
SDB(new SelectionDAGBuilder(*CurDAG, *FuncInfo, OL)),
GFI(),
OptLevel(OL),
DAGSize(0) {
initializeGCModuleInfoPass(*PassRegistry::getPassRegistry());
initializeAliasAnalysisAnalysisGroup(*PassRegistry::getPassRegistry());
initializeBranchProbabilityInfoPass(*PassRegistry::getPassRegistry());
initializeTargetLibraryInfoPass(*PassRegistry::getPassRegistry());
}
SelectionDAGISel::~SelectionDAGISel() {
delete SDB;
delete CurDAG;
delete FuncInfo;
}
void SelectionDAGISel::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<AliasAnalysis>();
AU.addPreserved<AliasAnalysis>();
AU.addRequired<GCModuleInfo>();
AU.addPreserved<GCModuleInfo>();
AU.addRequired<TargetLibraryInfo>();
if (UseMBPI && OptLevel != CodeGenOpt::None)
AU.addRequired<BranchProbabilityInfo>();
MachineFunctionPass::getAnalysisUsage(AU);
}
/// SplitCriticalSideEffectEdges - Look for critical edges with a PHI value that
/// may trap on it. In this case we have to split the edge so that the path
/// through the predecessor block that doesn't go to the phi block doesn't
/// execute the possibly trapping instruction.
///
/// This is required for correctness, so it must be done at -O0.
///
static void SplitCriticalSideEffectEdges(Function &Fn, Pass *SDISel) {
// Loop for blocks with phi nodes.
for (Function::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) {
PHINode *PN = dyn_cast<PHINode>(BB->begin());
if (PN == 0) continue;
ReprocessBlock:
// For each block with a PHI node, check to see if any of the input values
// are potentially trapping constant expressions. Constant expressions are
// the only potentially trapping value that can occur as the argument to a
// PHI.
for (BasicBlock::iterator I = BB->begin(); (PN = dyn_cast<PHINode>(I)); ++I)
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
ConstantExpr *CE = dyn_cast<ConstantExpr>(PN->getIncomingValue(i));
if (CE == 0 || !CE->canTrap()) continue;
// The only case we have to worry about is when the edge is critical.
// Since this block has a PHI Node, we assume it has multiple input
// edges: check to see if the pred has multiple successors.
BasicBlock *Pred = PN->getIncomingBlock(i);
if (Pred->getTerminator()->getNumSuccessors() == 1)
continue;
// Okay, we have to split this edge.
SplitCriticalEdge(Pred->getTerminator(),
GetSuccessorNumber(Pred, BB), SDISel, true);
goto ReprocessBlock;
}
}
}
bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
// Do some sanity-checking on the command-line options.
assert((!EnableFastISelVerbose || TM.Options.EnableFastISel) &&
"-fast-isel-verbose requires -fast-isel");
assert((!EnableFastISelAbort || TM.Options.EnableFastISel) &&
"-fast-isel-abort requires -fast-isel");
const Function &Fn = *mf.getFunction();
const TargetInstrInfo &TII = *TM.getInstrInfo();
const TargetRegisterInfo &TRI = *TM.getRegisterInfo();
MF = &mf;
RegInfo = &MF->getRegInfo();
AA = &getAnalysis<AliasAnalysis>();
LibInfo = &getAnalysis<TargetLibraryInfo>();
GFI = Fn.hasGC() ? &getAnalysis<GCModuleInfo>().getFunctionInfo(Fn) : 0;
DEBUG(dbgs() << "\n\n\n=== " << Fn.getName() << "\n");
SplitCriticalSideEffectEdges(const_cast<Function&>(Fn), this);
CurDAG->init(*MF);
FuncInfo->set(Fn, *MF);
if (UseMBPI && OptLevel != CodeGenOpt::None)
FuncInfo->BPI = &getAnalysis<BranchProbabilityInfo>();
else
FuncInfo->BPI = 0;
SDB->init(GFI, *AA, LibInfo);
SelectAllBasicBlocks(Fn);
// If the first basic block in the function has live ins that need to be
// copied into vregs, emit the copies into the top of the block before
// emitting the code for the block.
MachineBasicBlock *EntryMBB = MF->begin();
RegInfo->EmitLiveInCopies(EntryMBB, TRI, TII);
DenseMap<unsigned, unsigned> LiveInMap;
if (!FuncInfo->ArgDbgValues.empty())
for (MachineRegisterInfo::livein_iterator LI = RegInfo->livein_begin(),
E = RegInfo->livein_end(); LI != E; ++LI)
if (LI->second)
LiveInMap.insert(std::make_pair(LI->first, LI->second));
// Insert DBG_VALUE instructions for function arguments to the entry block.
for (unsigned i = 0, e = FuncInfo->ArgDbgValues.size(); i != e; ++i) {
MachineInstr *MI = FuncInfo->ArgDbgValues[e-i-1];
unsigned Reg = MI->getOperand(0).getReg();
if (TargetRegisterInfo::isPhysicalRegister(Reg))
EntryMBB->insert(EntryMBB->begin(), MI);
else {
MachineInstr *Def = RegInfo->getVRegDef(Reg);
MachineBasicBlock::iterator InsertPos = Def;
// FIXME: VR def may not be in entry block.
Def->getParent()->insert(llvm::next(InsertPos), MI);
}
// If Reg is live-in then update debug info to track its copy in a vreg.
DenseMap<unsigned, unsigned>::iterator LDI = LiveInMap.find(Reg);
if (LDI != LiveInMap.end()) {
MachineInstr *Def = RegInfo->getVRegDef(LDI->second);
MachineBasicBlock::iterator InsertPos = Def;
const MDNode *Variable =
MI->getOperand(MI->getNumOperands()-1).getMetadata();
unsigned Offset = MI->getOperand(1).getImm();
// Def is never a terminator here, so it is ok to increment InsertPos.
BuildMI(*EntryMBB, ++InsertPos, MI->getDebugLoc(),
TII.get(TargetOpcode::DBG_VALUE))
.addReg(LDI->second, RegState::Debug)
.addImm(Offset).addMetadata(Variable);
// If this vreg is directly copied into an exported register then
// that COPY instructions also need DBG_VALUE, if it is the only
// user of LDI->second.
MachineInstr *CopyUseMI = NULL;
for (MachineRegisterInfo::use_iterator
UI = RegInfo->use_begin(LDI->second);
MachineInstr *UseMI = UI.skipInstruction();) {
if (UseMI->isDebugValue()) continue;
if (UseMI->isCopy() && !CopyUseMI && UseMI->getParent() == EntryMBB) {
CopyUseMI = UseMI; continue;
}
// Otherwise this is another use or second copy use.
CopyUseMI = NULL; break;
}
if (CopyUseMI) {
MachineInstr *NewMI =
BuildMI(*MF, CopyUseMI->getDebugLoc(),
TII.get(TargetOpcode::DBG_VALUE))
.addReg(CopyUseMI->getOperand(0).getReg(), RegState::Debug)
.addImm(Offset).addMetadata(Variable);
MachineBasicBlock::iterator Pos = CopyUseMI;
EntryMBB->insertAfter(Pos, NewMI);
}
}
}
// Determine if there are any calls in this machine function.
MachineFrameInfo *MFI = MF->getFrameInfo();
if (!MFI->hasCalls()) {
for (MachineFunction::const_iterator
I = MF->begin(), E = MF->end(); I != E; ++I) {
const MachineBasicBlock *MBB = I;
for (MachineBasicBlock::const_iterator
II = MBB->begin(), IE = MBB->end(); II != IE; ++II) {
const MCInstrDesc &MCID = TM.getInstrInfo()->get(II->getOpcode());
if ((MCID.isCall() && !MCID.isReturn()) ||
II->isStackAligningInlineAsm()) {
MFI->setHasCalls(true);
goto done;
}
}
}
done:;
}
// Determine if there is a call to setjmp in the machine function.
MF->setExposesReturnsTwice(Fn.callsFunctionThatReturnsTwice());
// Replace forward-declared registers with the registers containing
// the desired value.
MachineRegisterInfo &MRI = MF->getRegInfo();
for (DenseMap<unsigned, unsigned>::iterator
I = FuncInfo->RegFixups.begin(), E = FuncInfo->RegFixups.end();
I != E; ++I) {
unsigned From = I->first;
unsigned To = I->second;
// If To is also scheduled to be replaced, find what its ultimate
// replacement is.
for (;;) {
DenseMap<unsigned, unsigned>::iterator J =
FuncInfo->RegFixups.find(To);
if (J == E) break;
To = J->second;
}
// Replace it.
MRI.replaceRegWith(From, To);
}
// Release function-specific state. SDB and CurDAG are already cleared
// at this point.
FuncInfo->clear();
return true;
}
void SelectionDAGISel::SelectBasicBlock(BasicBlock::const_iterator Begin,
BasicBlock::const_iterator End,
bool &HadTailCall) {
// Lower all of the non-terminator instructions. If a call is emitted
// as a tail call, cease emitting nodes for this block. Terminators
// are handled below.
for (BasicBlock::const_iterator I = Begin; I != End && !SDB->HasTailCall; ++I)
SDB->visit(*I);
// Make sure the root of the DAG is up-to-date.
CurDAG->setRoot(SDB->getControlRoot());
HadTailCall = SDB->HasTailCall;
SDB->clear();
// Final step, emit the lowered DAG as machine code.
CodeGenAndEmitDAG();
}
void SelectionDAGISel::ComputeLiveOutVRegInfo() {
SmallPtrSet<SDNode*, 128> VisitedNodes;
SmallVector<SDNode*, 128> Worklist;
Worklist.push_back(CurDAG->getRoot().getNode());
APInt Mask;
APInt KnownZero;
APInt KnownOne;
do {
SDNode *N = Worklist.pop_back_val();
// If we've already seen this node, ignore it.
if (!VisitedNodes.insert(N))
continue;
// Otherwise, add all chain operands to the worklist.
for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
if (N->getOperand(i).getValueType() == MVT::Other)
Worklist.push_back(N->getOperand(i).getNode());
// If this is a CopyToReg with a vreg dest, process it.
if (N->getOpcode() != ISD::CopyToReg)
continue;
unsigned DestReg = cast<RegisterSDNode>(N->getOperand(1))->getReg();
if (!TargetRegisterInfo::isVirtualRegister(DestReg))
continue;
// Ignore non-scalar or non-integer values.
SDValue Src = N->getOperand(2);
EVT SrcVT = Src.getValueType();
if (!SrcVT.isInteger() || SrcVT.isVector())
continue;
unsigned NumSignBits = CurDAG->ComputeNumSignBits(Src);
Mask = APInt::getAllOnesValue(SrcVT.getSizeInBits());
CurDAG->ComputeMaskedBits(Src, Mask, KnownZero, KnownOne);
FuncInfo->AddLiveOutRegInfo(DestReg, NumSignBits, KnownZero, KnownOne);
} while (!Worklist.empty());
}
void SelectionDAGISel::CodeGenAndEmitDAG() {
std::string GroupName;
if (TimePassesIsEnabled)
GroupName = "Instruction Selection and Scheduling";
std::string BlockName;
int BlockNumber = -1;
(void)BlockNumber;
#ifdef NDEBUG
if (ViewDAGCombine1 || ViewLegalizeTypesDAGs || ViewLegalizeDAGs ||
ViewDAGCombine2 || ViewDAGCombineLT || ViewISelDAGs || ViewSchedDAGs ||
ViewSUnitDAGs)
#endif
{
BlockNumber = FuncInfo->MBB->getNumber();
BlockName = MF->getFunction()->getName().str() + ":" +
FuncInfo->MBB->getBasicBlock()->getName().str();
}
DEBUG(dbgs() << "Initial selection DAG: BB#" << BlockNumber
<< " '" << BlockName << "'\n"; CurDAG->dump());
if (ViewDAGCombine1) CurDAG->viewGraph("dag-combine1 input for " + BlockName);
// Run the DAG combiner in pre-legalize mode.
{
NamedRegionTimer T("DAG Combining 1", GroupName, TimePassesIsEnabled);
CurDAG->Combine(BeforeLegalizeTypes, *AA, OptLevel);
}
DEBUG(dbgs() << "Optimized lowered selection DAG: BB#" << BlockNumber
<< " '" << BlockName << "'\n"; CurDAG->dump());
// Second step, hack on the DAG until it only uses operations and types that
// the target supports.
if (ViewLegalizeTypesDAGs) CurDAG->viewGraph("legalize-types input for " +
BlockName);
bool Changed;
{
NamedRegionTimer T("Type Legalization", GroupName, TimePassesIsEnabled);
Changed = CurDAG->LegalizeTypes();
}
DEBUG(dbgs() << "Type-legalized selection DAG: BB#" << BlockNumber
<< " '" << BlockName << "'\n"; CurDAG->dump());
if (Changed) {
if (ViewDAGCombineLT)
CurDAG->viewGraph("dag-combine-lt input for " + BlockName);
// Run the DAG combiner in post-type-legalize mode.
{
NamedRegionTimer T("DAG Combining after legalize types", GroupName,
TimePassesIsEnabled);
CurDAG->Combine(AfterLegalizeTypes, *AA, OptLevel);
}
DEBUG(dbgs() << "Optimized type-legalized selection DAG: BB#" << BlockNumber
<< " '" << BlockName << "'\n"; CurDAG->dump());
}
{
NamedRegionTimer T("Vector Legalization", GroupName, TimePassesIsEnabled);
Changed = CurDAG->LegalizeVectors();
}
if (Changed) {
{
NamedRegionTimer T("Type Legalization 2", GroupName, TimePassesIsEnabled);
CurDAG->LegalizeTypes();
}
if (ViewDAGCombineLT)
CurDAG->viewGraph("dag-combine-lv input for " + BlockName);
// Run the DAG combiner in post-type-legalize mode.
{
NamedRegionTimer T("DAG Combining after legalize vectors", GroupName,
TimePassesIsEnabled);
CurDAG->Combine(AfterLegalizeVectorOps, *AA, OptLevel);
}
DEBUG(dbgs() << "Optimized vector-legalized selection DAG: BB#"
<< BlockNumber << " '" << BlockName << "'\n"; CurDAG->dump());
}
if (ViewLegalizeDAGs) CurDAG->viewGraph("legalize input for " + BlockName);
{
NamedRegionTimer T("DAG Legalization", GroupName, TimePassesIsEnabled);
CurDAG->Legalize();
}
DEBUG(dbgs() << "Legalized selection DAG: BB#" << BlockNumber
<< " '" << BlockName << "'\n"; CurDAG->dump());
if (ViewDAGCombine2) CurDAG->viewGraph("dag-combine2 input for " + BlockName);
// Run the DAG combiner in post-legalize mode.
{
NamedRegionTimer T("DAG Combining 2", GroupName, TimePassesIsEnabled);
CurDAG->Combine(AfterLegalizeDAG, *AA, OptLevel);
}
DEBUG(dbgs() << "Optimized legalized selection DAG: BB#" << BlockNumber
<< " '" << BlockName << "'\n"; CurDAG->dump());
if (OptLevel != CodeGenOpt::None)
ComputeLiveOutVRegInfo();
if (ViewISelDAGs) CurDAG->viewGraph("isel input for " + BlockName);
// Third, instruction select all of the operations to machine code, adding the
// code to the MachineBasicBlock.
{
NamedRegionTimer T("Instruction Selection", GroupName, TimePassesIsEnabled);
DoInstructionSelection();
}
DEBUG(dbgs() << "Selected selection DAG: BB#" << BlockNumber
<< " '" << BlockName << "'\n"; CurDAG->dump());
if (ViewSchedDAGs) CurDAG->viewGraph("scheduler input for " + BlockName);
// Schedule machine code.
ScheduleDAGSDNodes *Scheduler = CreateScheduler();
{
NamedRegionTimer T("Instruction Scheduling", GroupName,
TimePassesIsEnabled);
Scheduler->Run(CurDAG, FuncInfo->MBB);
}
if (ViewSUnitDAGs) Scheduler->viewGraph();
// Emit machine code to BB. This can change 'BB' to the last block being
// inserted into.
MachineBasicBlock *FirstMBB = FuncInfo->MBB, *LastMBB;
{
NamedRegionTimer T("Instruction Creation", GroupName, TimePassesIsEnabled);
// FuncInfo->InsertPt is passed by reference and set to the end of the
// scheduled instructions.
LastMBB = FuncInfo->MBB = Scheduler->EmitSchedule(FuncInfo->InsertPt);
}
// If the block was split, make sure we update any references that are used to
// update PHI nodes later on.
if (FirstMBB != LastMBB)
SDB->UpdateSplitBlock(FirstMBB, LastMBB);
// Free the scheduler state.
{
NamedRegionTimer T("Instruction Scheduling Cleanup", GroupName,
TimePassesIsEnabled);
delete Scheduler;
}
// Free the SelectionDAG state, now that we're finished with it.
CurDAG->clear();
}
void SelectionDAGISel::DoInstructionSelection() {
DEBUG(errs() << "===== Instruction selection begins: BB#"
<< FuncInfo->MBB->getNumber()
<< " '" << FuncInfo->MBB->getName() << "'\n");
PreprocessISelDAG();
// Select target instructions for the DAG.
{
// Number all nodes with a topological order and set DAGSize.
DAGSize = CurDAG->AssignTopologicalOrder();
// Create a dummy node (which is not added to allnodes), that adds
// a reference to the root node, preventing it from being deleted,
// and tracking any changes of the root.
HandleSDNode Dummy(CurDAG->getRoot());
ISelPosition = SelectionDAG::allnodes_iterator(CurDAG->getRoot().getNode());
++ISelPosition;
// The AllNodes list is now topological-sorted. Visit the
// nodes by starting at the end of the list (the root of the
// graph) and preceding back toward the beginning (the entry
// node).
while (ISelPosition != CurDAG->allnodes_begin()) {
SDNode *Node = --ISelPosition;
// Skip dead nodes. DAGCombiner is expected to eliminate all dead nodes,
// but there are currently some corner cases that it misses. Also, this
// makes it theoretically possible to disable the DAGCombiner.
if (Node->use_empty())
continue;
SDNode *ResNode = Select(Node);
// FIXME: This is pretty gross. 'Select' should be changed to not return
// anything at all and this code should be nuked with a tactical strike.
// If node should not be replaced, continue with the next one.
if (ResNode == Node || Node->getOpcode() == ISD::DELETED_NODE)
continue;
// Replace node.
if (ResNode)
ReplaceUses(Node, ResNode);
// If after the replacement this node is not used any more,
// remove this dead node.
if (Node->use_empty()) { // Don't delete EntryToken, etc.
ISelUpdater ISU(ISelPosition);
CurDAG->RemoveDeadNode(Node, &ISU);
}
}
CurDAG->setRoot(Dummy.getValue());
}
DEBUG(errs() << "===== Instruction selection ends:\n");
PostprocessISelDAG();
}
/// PrepareEHLandingPad - Emit an EH_LABEL, set up live-in registers, and
/// do other setup for EH landing-pad blocks.
void SelectionDAGISel::PrepareEHLandingPad() {
MachineBasicBlock *MBB = FuncInfo->MBB;
// Add a label to mark the beginning of the landing pad. Deletion of the
// landing pad can thus be detected via the MachineModuleInfo.
MCSymbol *Label = MF->getMMI().addLandingPad(MBB);
// Assign the call site to the landing pad's begin label.
MF->getMMI().setCallSiteLandingPad(Label, SDB->LPadToCallSiteMap[MBB]);
const MCInstrDesc &II = TM.getInstrInfo()->get(TargetOpcode::EH_LABEL);
BuildMI(*MBB, FuncInfo->InsertPt, SDB->getCurDebugLoc(), II)
.addSym(Label);
// Mark exception register as live in.
unsigned Reg = TLI.getExceptionPointerRegister();
if (Reg) MBB->addLiveIn(Reg);
// Mark exception selector register as live in.
Reg = TLI.getExceptionSelectorRegister();
if (Reg) MBB->addLiveIn(Reg);
}
/// TryToFoldFastISelLoad - We're checking to see if we can fold the specified
/// load into the specified FoldInst. Note that we could have a sequence where
/// multiple LLVM IR instructions are folded into the same machineinstr. For
/// example we could have:
/// A: x = load i32 *P
/// B: y = icmp A, 42
/// C: br y, ...
///
/// In this scenario, LI is "A", and FoldInst is "C". We know about "B" (and
/// any other folded instructions) because it is between A and C.
///
/// If we succeed in folding the load into the operation, return true.
///
bool SelectionDAGISel::TryToFoldFastISelLoad(const LoadInst *LI,
const Instruction *FoldInst,
FastISel *FastIS) {
// We know that the load has a single use, but don't know what it is. If it
// isn't one of the folded instructions, then we can't succeed here. Handle
// this by scanning the single-use users of the load until we get to FoldInst.
unsigned MaxUsers = 6; // Don't scan down huge single-use chains of instrs.
const Instruction *TheUser = LI->use_back();
while (TheUser != FoldInst && // Scan up until we find FoldInst.
// Stay in the right block.
TheUser->getParent() == FoldInst->getParent() &&
--MaxUsers) { // Don't scan too far.
// If there are multiple or no uses of this instruction, then bail out.
if (!TheUser->hasOneUse())
return false;
TheUser = TheUser->use_back();
}
// If we didn't find the fold instruction, then we failed to collapse the
// sequence.
if (TheUser != FoldInst)
return false;
// Don't try to fold volatile loads. Target has to deal with alignment
// constraints.
if (LI->isVolatile()) return false;
// Figure out which vreg this is going into. If there is no assigned vreg yet
// then there actually was no reference to it. Perhaps the load is referenced
// by a dead instruction.
unsigned LoadReg = FastIS->getRegForValue(LI);
if (LoadReg == 0)
return false;
// Check to see what the uses of this vreg are. If it has no uses, or more
// than one use (at the machine instr level) then we can't fold it.
MachineRegisterInfo::reg_iterator RI = RegInfo->reg_begin(LoadReg);
if (RI == RegInfo->reg_end())
return false;
// See if there is exactly one use of the vreg. If there are multiple uses,
// then the instruction got lowered to multiple machine instructions or the
// use of the loaded value ended up being multiple operands of the result, in
// either case, we can't fold this.
MachineRegisterInfo::reg_iterator PostRI = RI; ++PostRI;
if (PostRI != RegInfo->reg_end())
return false;
assert(RI.getOperand().isUse() &&
"The only use of the vreg must be a use, we haven't emitted the def!");
MachineInstr *User = &*RI;
// Set the insertion point properly. Folding the load can cause generation of
// other random instructions (like sign extends) for addressing modes, make
// sure they get inserted in a logical place before the new instruction.
FuncInfo->InsertPt = User;
FuncInfo->MBB = User->getParent();
// Ask the target to try folding the load.
return FastIS->TryToFoldLoad(User, RI.getOperandNo(), LI);
}
/// isFoldedOrDeadInstruction - Return true if the specified instruction is
/// side-effect free and is either dead or folded into a generated instruction.
/// Return false if it needs to be emitted.
static bool isFoldedOrDeadInstruction(const Instruction *I,
FunctionLoweringInfo *FuncInfo) {
return !I->mayWriteToMemory() && // Side-effecting instructions aren't folded.
!isa<TerminatorInst>(I) && // Terminators aren't folded.
!isa<DbgInfoIntrinsic>(I) && // Debug instructions aren't folded.
!isa<LandingPadInst>(I) && // Landingpad instructions aren't folded.
!FuncInfo->isExportedInst(I); // Exported instrs must be computed.
}
#ifndef NDEBUG
// Collect per Instruction statistics for fast-isel misses. Only those
// instructions that cause the bail are accounted for. It does not account for
// instructions higher in the block. Thus, summing the per instructions stats
// will not add up to what is reported by NumFastIselFailures.
static void collectFailStats(const Instruction *I) {
switch (I->getOpcode()) {
default: assert (0 && "<Invalid operator> ");
// Terminators
case Instruction::Ret: NumFastIselFailRet++; return;
case Instruction::Br: NumFastIselFailBr++; return;
case Instruction::Switch: NumFastIselFailSwitch++; return;
case Instruction::IndirectBr: NumFastIselFailIndirectBr++; return;
case Instruction::Invoke: NumFastIselFailInvoke++; return;
case Instruction::Resume: NumFastIselFailResume++; return;
case Instruction::Unreachable: NumFastIselFailUnreachable++; return;
// Standard binary operators...
case Instruction::Add: NumFastIselFailAdd++; return;
case Instruction::FAdd: NumFastIselFailFAdd++; return;
case Instruction::Sub: NumFastIselFailSub++; return;
case Instruction::FSub: NumFastIselFailFSub++; return;
case Instruction::Mul: NumFastIselFailMul++; return;
case Instruction::FMul: NumFastIselFailFMul++; return;
case Instruction::UDiv: NumFastIselFailUDiv++; return;
case Instruction::SDiv: NumFastIselFailSDiv++; return;
case Instruction::FDiv: NumFastIselFailFDiv++; return;
case Instruction::URem: NumFastIselFailURem++; return;
case Instruction::SRem: NumFastIselFailSRem++; return;
case Instruction::FRem: NumFastIselFailFRem++; return;
// Logical operators...
case Instruction::And: NumFastIselFailAnd++; return;
case Instruction::Or: NumFastIselFailOr++; return;
case Instruction::Xor: NumFastIselFailXor++; return;
// Memory instructions...
case Instruction::Alloca: NumFastIselFailAlloca++; return;
case Instruction::Load: NumFastIselFailLoad++; return;
case Instruction::Store: NumFastIselFailStore++; return;
case Instruction::AtomicCmpXchg: NumFastIselFailAtomicCmpXchg++; return;
case Instruction::AtomicRMW: NumFastIselFailAtomicRMW++; return;
case Instruction::Fence: NumFastIselFailFence++; return;
case Instruction::GetElementPtr: NumFastIselFailGetElementPtr++; return;
// Convert instructions...
case Instruction::Trunc: NumFastIselFailTrunc++; return;
case Instruction::ZExt: NumFastIselFailZExt++; return;
case Instruction::SExt: NumFastIselFailSExt++; return;
case Instruction::FPTrunc: NumFastIselFailFPTrunc++; return;
case Instruction::FPExt: NumFastIselFailFPExt++; return;
case Instruction::FPToUI: NumFastIselFailFPToUI++; return;
case Instruction::FPToSI: NumFastIselFailFPToSI++; return;
case Instruction::UIToFP: NumFastIselFailUIToFP++; return;
case Instruction::SIToFP: NumFastIselFailSIToFP++; return;
case Instruction::IntToPtr: NumFastIselFailIntToPtr++; return;
case Instruction::PtrToInt: NumFastIselFailPtrToInt++; return;
case Instruction::BitCast: NumFastIselFailBitCast++; return;
// Other instructions...
case Instruction::ICmp: NumFastIselFailICmp++; return;
case Instruction::FCmp: NumFastIselFailFCmp++; return;
case Instruction::PHI: NumFastIselFailPHI++; return;
case Instruction::Select: NumFastIselFailSelect++; return;
case Instruction::Call: NumFastIselFailCall++; return;
case Instruction::Shl: NumFastIselFailShl++; return;
case Instruction::LShr: NumFastIselFailLShr++; return;
case Instruction::AShr: NumFastIselFailAShr++; return;
case Instruction::VAArg: NumFastIselFailVAArg++; return;
case Instruction::ExtractElement: NumFastIselFailExtractElement++; return;
case Instruction::InsertElement: NumFastIselFailInsertElement++; return;
case Instruction::ShuffleVector: NumFastIselFailShuffleVector++; return;
case Instruction::ExtractValue: NumFastIselFailExtractValue++; return;
case Instruction::InsertValue: NumFastIselFailInsertValue++; return;
case Instruction::LandingPad: NumFastIselFailLandingPad++; return;
}
}
#endif
void SelectionDAGISel::SelectAllBasicBlocks(const Function &Fn) {
// Initialize the Fast-ISel state, if needed.
FastISel *FastIS = 0;
if (TM.Options.EnableFastISel)
FastIS = TLI.createFastISel(*FuncInfo);
// Iterate over all basic blocks in the function.
ReversePostOrderTraversal<const Function*> RPOT(&Fn);
for (ReversePostOrderTraversal<const Function*>::rpo_iterator
I = RPOT.begin(), E = RPOT.end(); I != E; ++I) {
const BasicBlock *LLVMBB = *I;
if (OptLevel != CodeGenOpt::None) {
bool AllPredsVisited = true;
for (const_pred_iterator PI = pred_begin(LLVMBB), PE = pred_end(LLVMBB);
PI != PE; ++PI) {
if (!FuncInfo->VisitedBBs.count(*PI)) {
AllPredsVisited = false;
break;
}
}
if (AllPredsVisited) {
for (BasicBlock::const_iterator I = LLVMBB->begin();
isa<PHINode>(I); ++I)
FuncInfo->ComputePHILiveOutRegInfo(cast<PHINode>(I));
} else {
for (BasicBlock::const_iterator I = LLVMBB->begin();
isa<PHINode>(I); ++I)
FuncInfo->InvalidatePHILiveOutRegInfo(cast<PHINode>(I));
}
FuncInfo->VisitedBBs.insert(LLVMBB);
}
FuncInfo->MBB = FuncInfo->MBBMap[LLVMBB];
FuncInfo->InsertPt = FuncInfo->MBB->getFirstNonPHI();
BasicBlock::const_iterator const Begin = LLVMBB->getFirstNonPHI();
BasicBlock::const_iterator const End = LLVMBB->end();
BasicBlock::const_iterator BI = End;
FuncInfo->InsertPt = FuncInfo->MBB->getFirstNonPHI();
// Setup an EH landing-pad block.
if (FuncInfo->MBB->isLandingPad())
PrepareEHLandingPad();
// Lower any arguments needed in this block if this is the entry block.
if (LLVMBB == &Fn.getEntryBlock())
LowerArguments(LLVMBB);
// Before doing SelectionDAG ISel, see if FastISel has been requested.
if (FastIS) {
FastIS->startNewBlock();
// Emit code for any incoming arguments. This must happen before
// beginning FastISel on the entry block.
if (LLVMBB == &Fn.getEntryBlock()) {
CurDAG->setRoot(SDB->getControlRoot());
SDB->clear();
CodeGenAndEmitDAG();
// If we inserted any instructions at the beginning, make a note of
// where they are, so we can be sure to emit subsequent instructions
// after them.
if (FuncInfo->InsertPt != FuncInfo->MBB->begin())
FastIS->setLastLocalValue(llvm::prior(FuncInfo->InsertPt));
else
FastIS->setLastLocalValue(0);
}
unsigned NumFastIselRemaining = std::distance(Begin, End);
// Do FastISel on as many instructions as possible.
for (; BI != Begin; --BI) {
const Instruction *Inst = llvm::prior(BI);
// If we no longer require this instruction, skip it.
if (isFoldedOrDeadInstruction(Inst, FuncInfo)) {
--NumFastIselRemaining;
continue;
}
// Bottom-up: reset the insert pos at the top, after any local-value
// instructions.
FastIS->recomputeInsertPt();
// Try to select the instruction with FastISel.
if (FastIS->SelectInstruction(Inst)) {
--NumFastIselRemaining;
++NumFastIselSuccess;
// If fast isel succeeded, skip over all the folded instructions, and
// then see if there is a load right before the selected instructions.
// Try to fold the load if so.
const Instruction *BeforeInst = Inst;
while (BeforeInst != Begin) {
BeforeInst = llvm::prior(BasicBlock::const_iterator(BeforeInst));
if (!isFoldedOrDeadInstruction(BeforeInst, FuncInfo))
break;
}
if (BeforeInst != Inst && isa<LoadInst>(BeforeInst) &&
BeforeInst->hasOneUse() &&
TryToFoldFastISelLoad(cast<LoadInst>(BeforeInst), Inst, FastIS)) {
// If we succeeded, don't re-select the load.
BI = llvm::next(BasicBlock::const_iterator(BeforeInst));
--NumFastIselRemaining;
++NumFastIselSuccess;
}
continue;
}
#ifndef NDEBUG
if (EnableFastISelVerbose2)
collectFailStats(Inst);
#endif
// Then handle certain instructions as single-LLVM-Instruction blocks.
if (isa<CallInst>(Inst)) {
if (EnableFastISelVerbose || EnableFastISelAbort) {
dbgs() << "FastISel missed call: ";
Inst->dump();
}
if (!Inst->getType()->isVoidTy() && !Inst->use_empty()) {
unsigned &R = FuncInfo->ValueMap[Inst];
if (!R)
R = FuncInfo->CreateRegs(Inst->getType());
}
bool HadTailCall = false;
SelectBasicBlock(Inst, BI, HadTailCall);
// Recompute NumFastIselRemaining as Selection DAG instruction
// selection may have handled the call, input args, etc.
unsigned RemainingNow = std::distance(Begin, BI);
NumFastIselFailures += NumFastIselRemaining - RemainingNow;
// If the call was emitted as a tail call, we're done with the block.
if (HadTailCall) {
--BI;
break;
}
NumFastIselRemaining = RemainingNow;
continue;
}
if (isa<TerminatorInst>(Inst) && !isa<BranchInst>(Inst)) {
// Don't abort, and use a different message for terminator misses.
NumFastIselFailures += NumFastIselRemaining;
if (EnableFastISelVerbose || EnableFastISelAbort) {
dbgs() << "FastISel missed terminator: ";
Inst->dump();
}
} else {
NumFastIselFailures += NumFastIselRemaining;
if (EnableFastISelVerbose || EnableFastISelAbort) {
dbgs() << "FastISel miss: ";
Inst->dump();
}
if (EnableFastISelAbort)
// The "fast" selector couldn't handle something and bailed.
// For the purpose of debugging, just abort.
llvm_unreachable("FastISel didn't select the entire block");
}
break;
}
FastIS->recomputeInsertPt();
}
if (Begin != BI)
++NumDAGBlocks;
else
++NumFastIselBlocks;
if (Begin != BI) {
// Run SelectionDAG instruction selection on the remainder of the block
// not handled by FastISel. If FastISel is not run, this is the entire
// block.
bool HadTailCall;
SelectBasicBlock(Begin, BI, HadTailCall);
}
FinishBasicBlock();
FuncInfo->PHINodesToUpdate.clear();
}
delete FastIS;
SDB->clearDanglingDebugInfo();
}
void
SelectionDAGISel::FinishBasicBlock() {
DEBUG(dbgs() << "Total amount of phi nodes to update: "
<< FuncInfo->PHINodesToUpdate.size() << "\n";
for (unsigned i = 0, e = FuncInfo->PHINodesToUpdate.size(); i != e; ++i)
dbgs() << "Node " << i << " : ("
<< FuncInfo->PHINodesToUpdate[i].first
<< ", " << FuncInfo->PHINodesToUpdate[i].second << ")\n");
// Next, now that we know what the last MBB the LLVM BB expanded is, update
// PHI nodes in successors.
if (SDB->SwitchCases.empty() &&
SDB->JTCases.empty() &&
SDB->BitTestCases.empty()) {
for (unsigned i = 0, e = FuncInfo->PHINodesToUpdate.size(); i != e; ++i) {
MachineInstr *PHI = FuncInfo->PHINodesToUpdate[i].first;
assert(PHI->isPHI() &&
"This is not a machine PHI node that we are updating!");
if (!FuncInfo->MBB->isSuccessor(PHI->getParent()))
continue;
PHI->addOperand(
MachineOperand::CreateReg(FuncInfo->PHINodesToUpdate[i].second, false));
PHI->addOperand(MachineOperand::CreateMBB(FuncInfo->MBB));
}
return;
}
for (unsigned i = 0, e = SDB->BitTestCases.size(); i != e; ++i) {
// Lower header first, if it wasn't already lowered
if (!SDB->BitTestCases[i].Emitted) {
// Set the current basic block to the mbb we wish to insert the code into
FuncInfo->MBB = SDB->BitTestCases[i].Parent;
FuncInfo->InsertPt = FuncInfo->MBB->end();
// Emit the code
SDB->visitBitTestHeader(SDB->BitTestCases[i], FuncInfo->MBB);
CurDAG->setRoot(SDB->getRoot());
SDB->clear();
CodeGenAndEmitDAG();
}
for (unsigned j = 0, ej = SDB->BitTestCases[i].Cases.size(); j != ej; ++j) {
// Set the current basic block to the mbb we wish to insert the code into
FuncInfo->MBB = SDB->BitTestCases[i].Cases[j].ThisBB;
FuncInfo->InsertPt = FuncInfo->MBB->end();
// Emit the code
if (j+1 != ej)
SDB->visitBitTestCase(SDB->BitTestCases[i],
SDB->BitTestCases[i].Cases[j+1].ThisBB,
SDB->BitTestCases[i].Reg,
SDB->BitTestCases[i].Cases[j],
FuncInfo->MBB);
else
SDB->visitBitTestCase(SDB->BitTestCases[i],
SDB->BitTestCases[i].Default,
SDB->BitTestCases[i].Reg,
SDB->BitTestCases[i].Cases[j],
FuncInfo->MBB);
CurDAG->setRoot(SDB->getRoot());
SDB->clear();
CodeGenAndEmitDAG();
}
// Update PHI Nodes
for (unsigned pi = 0, pe = FuncInfo->PHINodesToUpdate.size();
pi != pe; ++pi) {
MachineInstr *PHI = FuncInfo->PHINodesToUpdate[pi].first;
MachineBasicBlock *PHIBB = PHI->getParent();
assert(PHI->isPHI() &&
"This is not a machine PHI node that we are updating!");
// This is "default" BB. We have two jumps to it. From "header" BB and
// from last "case" BB.
if (PHIBB == SDB->BitTestCases[i].Default) {
PHI->addOperand(MachineOperand::
CreateReg(FuncInfo->PHINodesToUpdate[pi].second,
false));
PHI->addOperand(MachineOperand::CreateMBB(SDB->BitTestCases[i].Parent));
PHI->addOperand(MachineOperand::
CreateReg(FuncInfo->PHINodesToUpdate[pi].second,
false));
PHI->addOperand(MachineOperand::CreateMBB(SDB->BitTestCases[i].Cases.
back().ThisBB));
}
// One of "cases" BB.
for (unsigned j = 0, ej = SDB->BitTestCases[i].Cases.size();
j != ej; ++j) {
MachineBasicBlock* cBB = SDB->BitTestCases[i].Cases[j].ThisBB;
if (cBB->isSuccessor(PHIBB)) {
PHI->addOperand(MachineOperand::
CreateReg(FuncInfo->PHINodesToUpdate[pi].second,
false));
PHI->addOperand(MachineOperand::CreateMBB(cBB));
}
}
}
}
SDB->BitTestCases.clear();
// If the JumpTable record is filled in, then we need to emit a jump table.
// Updating the PHI nodes is tricky in this case, since we need to determine
// whether the PHI is a successor of the range check MBB or the jump table MBB
for (unsigned i = 0, e = SDB->JTCases.size(); i != e; ++i) {
// Lower header first, if it wasn't already lowered
if (!SDB->JTCases[i].first.Emitted) {
// Set the current basic block to the mbb we wish to insert the code into
FuncInfo->MBB = SDB->JTCases[i].first.HeaderBB;
FuncInfo->InsertPt = FuncInfo->MBB->end();
// Emit the code
SDB->visitJumpTableHeader(SDB->JTCases[i].second, SDB->JTCases[i].first,
FuncInfo->MBB);
CurDAG->setRoot(SDB->getRoot());
SDB->clear();
CodeGenAndEmitDAG();
}
// Set the current basic block to the mbb we wish to insert the code into
FuncInfo->MBB = SDB->JTCases[i].second.MBB;
FuncInfo->InsertPt = FuncInfo->MBB->end();
// Emit the code
SDB->visitJumpTable(SDB->JTCases[i].second);
CurDAG->setRoot(SDB->getRoot());
SDB->clear();
CodeGenAndEmitDAG();
// Update PHI Nodes
for (unsigned pi = 0, pe = FuncInfo->PHINodesToUpdate.size();
pi != pe; ++pi) {
MachineInstr *PHI = FuncInfo->PHINodesToUpdate[pi].first;
MachineBasicBlock *PHIBB = PHI->getParent();
assert(PHI->isPHI() &&
"This is not a machine PHI node that we are updating!");
// "default" BB. We can go there only from header BB.
if (PHIBB == SDB->JTCases[i].second.Default) {
PHI->addOperand
(MachineOperand::CreateReg(FuncInfo->PHINodesToUpdate[pi].second,
false));
PHI->addOperand
(MachineOperand::CreateMBB(SDB->JTCases[i].first.HeaderBB));
}
// JT BB. Just iterate over successors here
if (FuncInfo->MBB->isSuccessor(PHIBB)) {
PHI->addOperand
(MachineOperand::CreateReg(FuncInfo->PHINodesToUpdate[pi].second,
false));
PHI->addOperand(MachineOperand::CreateMBB(FuncInfo->MBB));
}
}
}
SDB->JTCases.clear();
// If the switch block involved a branch to one of the actual successors, we
// need to update PHI nodes in that block.
for (unsigned i = 0, e = FuncInfo->PHINodesToUpdate.size(); i != e; ++i) {
MachineInstr *PHI = FuncInfo->PHINodesToUpdate[i].first;
assert(PHI->isPHI() &&
"This is not a machine PHI node that we are updating!");
if (FuncInfo->MBB->isSuccessor(PHI->getParent())) {
PHI->addOperand(
MachineOperand::CreateReg(FuncInfo->PHINodesToUpdate[i].second, false));
PHI->addOperand(MachineOperand::CreateMBB(FuncInfo->MBB));
}
}
// If we generated any switch lowering information, build and codegen any
// additional DAGs necessary.
for (unsigned i = 0, e = SDB->SwitchCases.size(); i != e; ++i) {
// Set the current basic block to the mbb we wish to insert the code into
FuncInfo->MBB = SDB->SwitchCases[i].ThisBB;
FuncInfo->InsertPt = FuncInfo->MBB->end();
// Determine the unique successors.
SmallVector<MachineBasicBlock *, 2> Succs;
Succs.push_back(SDB->SwitchCases[i].TrueBB);
if (SDB->SwitchCases[i].TrueBB != SDB->SwitchCases[i].FalseBB)
Succs.push_back(SDB->SwitchCases[i].FalseBB);
// Emit the code. Note that this could result in FuncInfo->MBB being split.
SDB->visitSwitchCase(SDB->SwitchCases[i], FuncInfo->MBB);
CurDAG->setRoot(SDB->getRoot());
SDB->clear();
CodeGenAndEmitDAG();
// Remember the last block, now that any splitting is done, for use in
// populating PHI nodes in successors.
MachineBasicBlock *ThisBB = FuncInfo->MBB;
// Handle any PHI nodes in successors of this chunk, as if we were coming
// from the original BB before switch expansion. Note that PHI nodes can
// occur multiple times in PHINodesToUpdate. We have to be very careful to
// handle them the right number of times.
for (unsigned i = 0, e = Succs.size(); i != e; ++i) {
FuncInfo->MBB = Succs[i];
FuncInfo->InsertPt = FuncInfo->MBB->end();
// FuncInfo->MBB may have been removed from the CFG if a branch was
// constant folded.
if (ThisBB->isSuccessor(FuncInfo->MBB)) {
for (MachineBasicBlock::iterator Phi = FuncInfo->MBB->begin();
Phi != FuncInfo->MBB->end() && Phi->isPHI();
++Phi) {
// This value for this PHI node is recorded in PHINodesToUpdate.
for (unsigned pn = 0; ; ++pn) {
assert(pn != FuncInfo->PHINodesToUpdate.size() &&
"Didn't find PHI entry!");
if (FuncInfo->PHINodesToUpdate[pn].first == Phi) {
Phi->addOperand(MachineOperand::
CreateReg(FuncInfo->PHINodesToUpdate[pn].second,
false));
Phi->addOperand(MachineOperand::CreateMBB(ThisBB));
break;
}
}
}
}
}
}
SDB->SwitchCases.clear();
}
/// Create the scheduler. If a specific scheduler was specified
/// via the SchedulerRegistry, use it, otherwise select the
/// one preferred by the target.
///
ScheduleDAGSDNodes *SelectionDAGISel::CreateScheduler() {
RegisterScheduler::FunctionPassCtor Ctor = RegisterScheduler::getDefault();
if (!Ctor) {
Ctor = ISHeuristic;
RegisterScheduler::setDefault(Ctor);
}
return Ctor(this, OptLevel);
}
//===----------------------------------------------------------------------===//
// Helper functions used by the generated instruction selector.
//===----------------------------------------------------------------------===//
// Calls to these methods are generated by tblgen.
/// CheckAndMask - The isel is trying to match something like (and X, 255). If
/// the dag combiner simplified the 255, we still want to match. RHS is the
/// actual value in the DAG on the RHS of an AND, and DesiredMaskS is the value
/// specified in the .td file (e.g. 255).
bool SelectionDAGISel::CheckAndMask(SDValue LHS, ConstantSDNode *RHS,
int64_t DesiredMaskS) const {
const APInt &ActualMask = RHS->getAPIntValue();
const APInt &DesiredMask = APInt(LHS.getValueSizeInBits(), DesiredMaskS);
// If the actual mask exactly matches, success!
if (ActualMask == DesiredMask)
return true;
// If the actual AND mask is allowing unallowed bits, this doesn't match.
if (ActualMask.intersects(~DesiredMask))
return false;
// Otherwise, the DAG Combiner may have proven that the value coming in is
// either already zero or is not demanded. Check for known zero input bits.
APInt NeededMask = DesiredMask & ~ActualMask;
if (CurDAG->MaskedValueIsZero(LHS, NeededMask))
return true;
// TODO: check to see if missing bits are just not demanded.
// Otherwise, this pattern doesn't match.
return false;
}
/// CheckOrMask - The isel is trying to match something like (or X, 255). If
/// the dag combiner simplified the 255, we still want to match. RHS is the
/// actual value in the DAG on the RHS of an OR, and DesiredMaskS is the value
/// specified in the .td file (e.g. 255).
bool SelectionDAGISel::CheckOrMask(SDValue LHS, ConstantSDNode *RHS,
int64_t DesiredMaskS) const {
const APInt &ActualMask = RHS->getAPIntValue();
const APInt &DesiredMask = APInt(LHS.getValueSizeInBits(), DesiredMaskS);
// If the actual mask exactly matches, success!
if (ActualMask == DesiredMask)
return true;
// If the actual AND mask is allowing unallowed bits, this doesn't match.
if (ActualMask.intersects(~DesiredMask))
return false;
// Otherwise, the DAG Combiner may have proven that the value coming in is
// either already zero or is not demanded. Check for known zero input bits.
APInt NeededMask = DesiredMask & ~ActualMask;
APInt KnownZero, KnownOne;
CurDAG->ComputeMaskedBits(LHS, NeededMask, KnownZero, KnownOne);
// If all the missing bits in the or are already known to be set, match!
if ((NeededMask & KnownOne) == NeededMask)
return true;
// TODO: check to see if missing bits are just not demanded.
// Otherwise, this pattern doesn't match.
return false;
}
/// SelectInlineAsmMemoryOperands - Calls to this are automatically generated
/// by tblgen. Others should not call it.
void SelectionDAGISel::
SelectInlineAsmMemoryOperands(std::vector<SDValue> &Ops) {
std::vector<SDValue> InOps;
std::swap(InOps, Ops);
Ops.push_back(InOps[InlineAsm::Op_InputChain]); // 0
Ops.push_back(InOps[InlineAsm::Op_AsmString]); // 1
Ops.push_back(InOps[InlineAsm::Op_MDNode]); // 2, !srcloc
Ops.push_back(InOps[InlineAsm::Op_ExtraInfo]); // 3 (SideEffect, AlignStack)
unsigned i = InlineAsm::Op_FirstOperand, e = InOps.size();
if (InOps[e-1].getValueType() == MVT::Glue)
--e; // Don't process a glue operand if it is here.
while (i != e) {
unsigned Flags = cast<ConstantSDNode>(InOps[i])->getZExtValue();
if (!InlineAsm::isMemKind(Flags)) {
// Just skip over this operand, copying the operands verbatim.
Ops.insert(Ops.end(), InOps.begin()+i,
InOps.begin()+i+InlineAsm::getNumOperandRegisters(Flags) + 1);
i += InlineAsm::getNumOperandRegisters(Flags) + 1;
} else {
assert(InlineAsm::getNumOperandRegisters(Flags) == 1 &&
"Memory operand with multiple values?");
// Otherwise, this is a memory operand. Ask the target to select it.
std::vector<SDValue> SelOps;
if (SelectInlineAsmMemoryOperand(InOps[i+1], 'm', SelOps))
report_fatal_error("Could not match memory address. Inline asm"
" failure!");
// Add this to the output node.
unsigned NewFlags =
InlineAsm::getFlagWord(InlineAsm::Kind_Mem, SelOps.size());
Ops.push_back(CurDAG->getTargetConstant(NewFlags, MVT::i32));
Ops.insert(Ops.end(), SelOps.begin(), SelOps.end());
i += 2;
}
}
// Add the glue input back if present.
if (e != InOps.size())
Ops.push_back(InOps.back());
}
/// findGlueUse - Return use of MVT::Glue value produced by the specified
/// SDNode.
///
static SDNode *findGlueUse(SDNode *N) {
unsigned FlagResNo = N->getNumValues()-1;
for (SDNode::use_iterator I = N->use_begin(), E = N->use_end(); I != E; ++I) {
SDUse &Use = I.getUse();
if (Use.getResNo() == FlagResNo)
return Use.getUser();
}
return NULL;
}
/// findNonImmUse - Return true if "Use" is a non-immediate use of "Def".
/// This function recursively traverses up the operand chain, ignoring
/// certain nodes.
static bool findNonImmUse(SDNode *Use, SDNode* Def, SDNode *ImmedUse,
SDNode *Root, SmallPtrSet<SDNode*, 16> &Visited,
bool IgnoreChains) {
// The NodeID's are given uniques ID's where a node ID is guaranteed to be
// greater than all of its (recursive) operands. If we scan to a point where
// 'use' is smaller than the node we're scanning for, then we know we will
// never find it.
//
// The Use may be -1 (unassigned) if it is a newly allocated node. This can
// happen because we scan down to newly selected nodes in the case of glue
// uses.
if ((Use->getNodeId() < Def->getNodeId() && Use->getNodeId() != -1))
return false;
// Don't revisit nodes if we already scanned it and didn't fail, we know we
// won't fail if we scan it again.
if (!Visited.insert(Use))
return false;
for (unsigned i = 0, e = Use->getNumOperands(); i != e; ++i) {
// Ignore chain uses, they are validated by HandleMergeInputChains.
if (Use->getOperand(i).getValueType() == MVT::Other && IgnoreChains)
continue;
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);
return true;
}
// Traverse up the operand chain.
if (findNonImmUse(N, Def, ImmedUse, Root, Visited, IgnoreChains))
return true;
}
return false;
}
/// IsProfitableToFold - Returns true if it's profitable to fold the specific
/// operand node N of U during instruction selection that starts at Root.
bool SelectionDAGISel::IsProfitableToFold(SDValue N, SDNode *U,
SDNode *Root) const {
if (OptLevel == CodeGenOpt::None) return false;
return N.hasOneUse();
}
/// IsLegalToFold - Returns true if the specific operand node N of
/// U can be folded during instruction selection that starts at Root.
bool SelectionDAGISel::IsLegalToFold(SDValue N, SDNode *U, SDNode *Root,
CodeGenOpt::Level OptLevel,
bool IgnoreChains) {
if (OptLevel == CodeGenOpt::None) 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 glue, then it gets (even more) interesting. Since it
// will be "glued" together with its glue use in the scheduler, we need to
// check if it might reach N.
//
// [N*] //
// ^ ^ //
// / \ //
// [U*] [X]? //
// ^ ^ //
// \ \ //
// \ | //
// [Root*] | //
// ^ | //
// f | //
// | / //
// [Y] / //
// ^ / //
// f / //
// | / //
// [GU] //
//
// If GU (glue use) indirectly reaches N (the load), and Root folds N
// (call it Fold), then X is a predecessor of GU and a successor of
// Fold. But since Fold and GU are glued together, this will create
// a cycle in the scheduling graph.
// If the node has glue, walk down the graph to the "lowest" node in the
// glueged set.
EVT VT = Root->getValueType(Root->getNumValues()-1);
while (VT == MVT::Glue) {
SDNode *GU = findGlueUse(Root);
if (GU == NULL)
break;
Root = GU;
VT = Root->getValueType(Root->getNumValues()-1);
// If our query node has a glue result with a use, we've walked up it. If
// the user (which has already been selected) has a chain or indirectly uses
// the chain, our WalkChainUsers predicate will not consider it. Because of
// this, we cannot ignore chains in this predicate.
IgnoreChains = false;
}
SmallPtrSet<SDNode*, 16> Visited;
return !findNonImmUse(Root, N.getNode(), U, Root, Visited, IgnoreChains);
}
SDNode *SelectionDAGISel::Select_INLINEASM(SDNode *N) {
std::vector<SDValue> Ops(N->op_begin(), N->op_end());
SelectInlineAsmMemoryOperands(Ops);
std::vector<EVT> VTs;
VTs.push_back(MVT::Other);
VTs.push_back(MVT::Glue);
SDValue New = CurDAG->getNode(ISD::INLINEASM, N->getDebugLoc(),
VTs, &Ops[0], Ops.size());
New->setNodeId(-1);
return New.getNode();
}
SDNode *SelectionDAGISel::Select_UNDEF(SDNode *N) {
return CurDAG->SelectNodeTo(N, TargetOpcode::IMPLICIT_DEF,N->getValueType(0));
}
/// GetVBR - decode a vbr encoding whose top bit is set.
LLVM_ATTRIBUTE_ALWAYS_INLINE static uint64_t
GetVBR(uint64_t Val, const unsigned char *MatcherTable, unsigned &Idx) {
assert(Val >= 128 && "Not a VBR");
Val &= 127; // Remove first vbr bit.
unsigned Shift = 7;
uint64_t NextBits;
do {
NextBits = MatcherTable[Idx++];
Val |= (NextBits&127) << Shift;
Shift += 7;
} while (NextBits & 128);
return Val;
}
/// UpdateChainsAndGlue - When a match is complete, this method updates uses of
/// interior glue and chain results to use the new glue and chain results.
void SelectionDAGISel::
UpdateChainsAndGlue(SDNode *NodeToMatch, SDValue InputChain,
const SmallVectorImpl<SDNode*> &ChainNodesMatched,
SDValue InputGlue,
const SmallVectorImpl<SDNode*> &GlueResultNodesMatched,
bool isMorphNodeTo) {
SmallVector<SDNode*, 4> NowDeadNodes;
ISelUpdater ISU(ISelPosition);
// Now that all the normal results are replaced, we replace the chain and
// glue results if present.
if (!ChainNodesMatched.empty()) {
assert(InputChain.getNode() != 0 &&
"Matched input chains but didn't produce a chain");
// Loop over all of the nodes we matched that produced a chain result.
// Replace all the chain results with the final chain we ended up with.
for (unsigned i = 0, e = ChainNodesMatched.size(); i != e; ++i) {
SDNode *ChainNode = ChainNodesMatched[i];
// If this node was already deleted, don't look at it.
if (ChainNode->getOpcode() == ISD::DELETED_NODE)
continue;
// Don't replace the results of the root node if we're doing a
// MorphNodeTo.
if (ChainNode == NodeToMatch && isMorphNodeTo)
continue;
SDValue ChainVal = SDValue(ChainNode, ChainNode->getNumValues()-1);
if (ChainVal.getValueType() == MVT::Glue)
ChainVal = ChainVal.getValue(ChainVal->getNumValues()-2);
assert(ChainVal.getValueType() == MVT::Other && "Not a chain?");
CurDAG->ReplaceAllUsesOfValueWith(ChainVal, InputChain, &ISU);
// If the node became dead and we haven't already seen it, delete it.
if (ChainNode->use_empty() &&
!std::count(NowDeadNodes.begin(), NowDeadNodes.end(), ChainNode))
NowDeadNodes.push_back(ChainNode);
}
}
// If the result produces glue, update any glue results in the matched
// pattern with the glue result.
if (InputGlue.getNode() != 0) {
// Handle any interior nodes explicitly marked.
for (unsigned i = 0, e = GlueResultNodesMatched.size(); i != e; ++i) {
SDNode *FRN = GlueResultNodesMatched[i];
// If this node was already deleted, don't look at it.
if (FRN->getOpcode() == ISD::DELETED_NODE)
continue;
assert(FRN->getValueType(FRN->getNumValues()-1) == MVT::Glue &&
"Doesn't have a glue result");
CurDAG->ReplaceAllUsesOfValueWith(SDValue(FRN, FRN->getNumValues()-1),
InputGlue, &ISU);
// If the node became dead and we haven't already seen it, delete it.
if (FRN->use_empty() &&
!std::count(NowDeadNodes.begin(), NowDeadNodes.end(), FRN))
NowDeadNodes.push_back(FRN);
}
}
if (!NowDeadNodes.empty())
CurDAG->RemoveDeadNodes(NowDeadNodes, &ISU);
DEBUG(errs() << "ISEL: Match complete!\n");
}
enum ChainResult {
CR_Simple,
CR_InducesCycle,
CR_LeadsToInteriorNode
};
/// WalkChainUsers - Walk down the users of the specified chained node that is
/// part of the pattern we're matching, looking at all of the users we find.
/// This determines whether something is an interior node, whether we have a
/// non-pattern node in between two pattern nodes (which prevent folding because
/// it would induce a cycle) and whether we have a TokenFactor node sandwiched
/// between pattern nodes (in which case the TF becomes part of the pattern).
///
/// The walk we do here is guaranteed to be small because we quickly get down to
/// already selected nodes "below" us.
static ChainResult
WalkChainUsers(SDNode *ChainedNode,
SmallVectorImpl<SDNode*> &ChainedNodesInPattern,
SmallVectorImpl<SDNode*> &InteriorChainedNodes) {
ChainResult Result = CR_Simple;
for (SDNode::use_iterator UI = ChainedNode->use_begin(),
E = ChainedNode->use_end(); UI != E; ++UI) {
// Make sure the use is of the chain, not some other value we produce.
if (UI.getUse().getValueType() != MVT::Other) continue;
SDNode *User = *UI;
// If we see an already-selected machine node, then we've gone beyond the
// pattern that we're selecting down into the already selected chunk of the
// DAG.
if (User->isMachineOpcode() ||
User->getOpcode() == ISD::HANDLENODE) // Root of the graph.
continue;
if (User->getOpcode() == ISD::CopyToReg ||
User->getOpcode() == ISD::CopyFromReg ||
User->getOpcode() == ISD::INLINEASM ||
User->getOpcode() == ISD::EH_LABEL) {
// If their node ID got reset to -1 then they've already been selected.
// Treat them like a MachineOpcode.
if (User->getNodeId() == -1)
continue;
}
// If we have a TokenFactor, we handle it specially.
if (User->getOpcode() != ISD::TokenFactor) {
// If the node isn't a token factor and isn't part of our pattern, then it
// must be a random chained node in between two nodes we're selecting.
// This happens when we have something like:
// x = load ptr
// call
// y = x+4
// store y -> ptr
// Because we structurally match the load/store as a read/modify/write,
// but the call is chained between them. We cannot fold in this case
// because it would induce a cycle in the graph.
if (!std::count(ChainedNodesInPattern.begin(),
ChainedNodesInPattern.end(), User))
return CR_InducesCycle;
// Otherwise we found a node that is part of our pattern. For example in:
// x = load ptr
// y = x+4
// store y -> ptr
// This would happen when we're scanning down from the load and see the
// store as a user. Record that there is a use of ChainedNode that is
// part of the pattern and keep scanning uses.
Result = CR_LeadsToInteriorNode;
InteriorChainedNodes.push_back(User);
continue;
}
// If we found a TokenFactor, there are two cases to consider: first if the
// TokenFactor is just hanging "below" the pattern we're matching (i.e. no
// uses of the TF are in our pattern) we just want to ignore it. Second,
// the TokenFactor can be sandwiched in between two chained nodes, like so:
// [Load chain]
// ^
// |
// [Load]
// ^ ^
// | \ DAG's like cheese
// / \ do you?
// / |
// [TokenFactor] [Op]
// ^ ^
// | |
// \ /
// \ /
// [Store]
//
// In this case, the TokenFactor becomes part of our match and we rewrite it
// as a new TokenFactor.
//
// To distinguish these two cases, do a recursive walk down the uses.
switch (WalkChainUsers(User, ChainedNodesInPattern, InteriorChainedNodes)) {
case CR_Simple:
// If the uses of the TokenFactor are just already-selected nodes, ignore
// it, it is "below" our pattern.
continue;
case CR_InducesCycle:
// If the uses of the TokenFactor lead to nodes that are not part of our
// pattern that are not selected, folding would turn this into a cycle,
// bail out now.
return CR_InducesCycle;
case CR_LeadsToInteriorNode:
break; // Otherwise, keep processing.
}
// Okay, we know we're in the interesting interior case. The TokenFactor
// is now going to be considered part of the pattern so that we rewrite its
// uses (it may have uses that are not part of the pattern) with the
// ultimate chain result of the generated code. We will also add its chain
// inputs as inputs to the ultimate TokenFactor we create.
Result = CR_LeadsToInteriorNode;
ChainedNodesInPattern.push_back(User);
InteriorChainedNodes.push_back(User);
continue;
}
return Result;
}
/// HandleMergeInputChains - This implements the OPC_EmitMergeInputChains
/// operation for when the pattern matched at least one node with a chains. The
/// input vector contains a list of all of the chained nodes that we match. We
/// must determine if this is a valid thing to cover (i.e. matching it won't
/// induce cycles in the DAG) and if so, creating a TokenFactor node. that will
/// be used as the input node chain for the generated nodes.
static SDValue
HandleMergeInputChains(SmallVectorImpl<SDNode*> &ChainNodesMatched,
SelectionDAG *CurDAG) {
// Walk all of the chained nodes we've matched, recursively scanning down the
// users of the chain result. This adds any TokenFactor nodes that are caught
// in between chained nodes to the chained and interior nodes list.
SmallVector<SDNode*, 3> InteriorChainedNodes;
for (unsigned i = 0, e = ChainNodesMatched.size(); i != e; ++i) {
if (WalkChainUsers(ChainNodesMatched[i], ChainNodesMatched,
InteriorChainedNodes) == CR_InducesCycle)
return SDValue(); // Would induce a cycle.
}
// Okay, we have walked all the matched nodes and collected TokenFactor nodes
// that we are interested in. Form our input TokenFactor node.
SmallVector<SDValue, 3> InputChains;
for (unsigned i = 0, e = ChainNodesMatched.size(); i != e; ++i) {
// Add the input chain of this node to the InputChains list (which will be
// the operands of the generated TokenFactor) if it's not an interior node.
SDNode *N = ChainNodesMatched[i];
if (N->getOpcode() != ISD::TokenFactor) {
if (std::count(InteriorChainedNodes.begin(),InteriorChainedNodes.end(),N))
continue;
// Otherwise, add the input chain.
SDValue InChain = ChainNodesMatched[i]->getOperand(0);
assert(InChain.getValueType() == MVT::Other && "Not a chain");
InputChains.push_back(InChain);
continue;
}
// If we have a token factor, we want to add all inputs of the token factor
// that are not part of the pattern we're matching.
for (unsigned op = 0, e = N->getNumOperands(); op != e; ++op) {
if (!std::count(ChainNodesMatched.begin(), ChainNodesMatched.end(),
N->getOperand(op).getNode()))
InputChains.push_back(N->getOperand(op));
}
}
SDValue Res;
if (InputChains.size() == 1)
return InputChains[0];
return CurDAG->getNode(ISD::TokenFactor, ChainNodesMatched[0]->getDebugLoc(),
MVT::Other, &InputChains[0], InputChains.size());
}
/// MorphNode - Handle morphing a node in place for the selector.
SDNode *SelectionDAGISel::
MorphNode(SDNode *Node, unsigned TargetOpc, SDVTList VTList,
const SDValue *Ops, unsigned NumOps, unsigned EmitNodeInfo) {
// It is possible we're using MorphNodeTo to replace a node with no
// normal results with one that has a normal result (or we could be
// adding a chain) and the input could have glue and chains as well.
// In this case we need to shift the operands down.
// FIXME: This is a horrible hack and broken in obscure cases, no worse
// than the old isel though.
int OldGlueResultNo = -1, OldChainResultNo = -1;
unsigned NTMNumResults = Node->getNumValues();
if (Node->getValueType(NTMNumResults-1) == MVT::Glue) {
OldGlueResultNo = NTMNumResults-1;
if (NTMNumResults != 1 &&
Node->getValueType(NTMNumResults-2) == MVT::Other)
OldChainResultNo = NTMNumResults-2;
} else if (Node->getValueType(NTMNumResults-1) == MVT::Other)
OldChainResultNo = NTMNumResults-1;
// Call the underlying SelectionDAG routine to do the transmogrification. Note
// that this deletes operands of the old node that become dead.
SDNode *Res = CurDAG->MorphNodeTo(Node, ~TargetOpc, VTList, Ops, NumOps);
// MorphNodeTo can operate in two ways: if an existing node with the
// specified operands exists, it can just return it. Otherwise, it
// updates the node in place to have the requested operands.
if (Res == Node) {
// If we updated the node in place, reset the node ID. To the isel,
// this should be just like a newly allocated machine node.
Res->setNodeId(-1);
}
unsigned ResNumResults = Res->getNumValues();
// Move the glue if needed.
if ((EmitNodeInfo & OPFL_GlueOutput) && OldGlueResultNo != -1 &&
(unsigned)OldGlueResultNo != ResNumResults-1)
CurDAG->ReplaceAllUsesOfValueWith(SDValue(Node, OldGlueResultNo),
SDValue(Res, ResNumResults-1));
if ((EmitNodeInfo & OPFL_GlueOutput) != 0)
--ResNumResults;
// Move the chain reference if needed.
if ((EmitNodeInfo & OPFL_Chain) && OldChainResultNo != -1 &&
(unsigned)OldChainResultNo != ResNumResults-1)
CurDAG->ReplaceAllUsesOfValueWith(SDValue(Node, OldChainResultNo),
SDValue(Res, ResNumResults-1));
// Otherwise, no replacement happened because the node already exists. Replace
// Uses of the old node with the new one.
if (Res != Node)
CurDAG->ReplaceAllUsesWith(Node, Res);
return Res;
}
/// CheckPatternPredicate - Implements OP_CheckPatternPredicate.
LLVM_ATTRIBUTE_ALWAYS_INLINE static bool
CheckSame(const unsigned char *MatcherTable, unsigned &MatcherIndex,
SDValue N,
const SmallVectorImpl<std::pair<SDValue, SDNode*> > &RecordedNodes) {
// Accept if it is exactly the same as a previously recorded node.
unsigned RecNo = MatcherTable[MatcherIndex++];
assert(RecNo < RecordedNodes.size() && "Invalid CheckSame");
return N == RecordedNodes[RecNo].first;
}
/// CheckPatternPredicate - Implements OP_CheckPatternPredicate.
LLVM_ATTRIBUTE_ALWAYS_INLINE static bool
CheckPatternPredicate(const unsigned char *MatcherTable, unsigned &MatcherIndex,
SelectionDAGISel &SDISel) {
return SDISel.CheckPatternPredicate(MatcherTable[MatcherIndex++]);
}
/// CheckNodePredicate - Implements OP_CheckNodePredicate.
LLVM_ATTRIBUTE_ALWAYS_INLINE static bool
CheckNodePredicate(const unsigned char *MatcherTable, unsigned &MatcherIndex,
SelectionDAGISel &SDISel, SDNode *N) {
return SDISel.CheckNodePredicate(N, MatcherTable[MatcherIndex++]);
}
LLVM_ATTRIBUTE_ALWAYS_INLINE static bool
CheckOpcode(const unsigned char *MatcherTable, unsigned &MatcherIndex,
SDNode *N) {
uint16_t Opc = MatcherTable[MatcherIndex++];
Opc |= (unsigned short)MatcherTable[MatcherIndex++] << 8;
return N->getOpcode() == Opc;
}
LLVM_ATTRIBUTE_ALWAYS_INLINE static bool
CheckType(const unsigned char *MatcherTable, unsigned &MatcherIndex,
SDValue N, const TargetLowering &TLI) {
MVT::SimpleValueType VT = (MVT::SimpleValueType)MatcherTable[MatcherIndex++];
if (N.getValueType() == VT) return true;
// Handle the case when VT is iPTR.
return VT == MVT::iPTR && N.getValueType() == TLI.getPointerTy();
}
LLVM_ATTRIBUTE_ALWAYS_INLINE static bool
CheckChildType(const unsigned char *MatcherTable, unsigned &MatcherIndex,
SDValue N, const TargetLowering &TLI,
unsigned ChildNo) {
if (ChildNo >= N.getNumOperands())
return false; // Match fails if out of range child #.
return ::CheckType(MatcherTable, MatcherIndex, N.getOperand(ChildNo), TLI);
}
LLVM_ATTRIBUTE_ALWAYS_INLINE static bool
CheckCondCode(const unsigned char *MatcherTable, unsigned &MatcherIndex,
SDValue N) {
return cast<CondCodeSDNode>(N)->get() ==
(ISD::CondCode)MatcherTable[MatcherIndex++];
}
LLVM_ATTRIBUTE_ALWAYS_INLINE static bool
CheckValueType(const unsigned char *MatcherTable, unsigned &MatcherIndex,
SDValue N, const TargetLowering &TLI) {
MVT::SimpleValueType VT = (MVT::SimpleValueType)MatcherTable[MatcherIndex++];
if (cast<VTSDNode>(N)->getVT() == VT)
return true;
// Handle the case when VT is iPTR.
return VT == MVT::iPTR && cast<VTSDNode>(N)->getVT() == TLI.getPointerTy();
}
LLVM_ATTRIBUTE_ALWAYS_INLINE static bool
CheckInteger(const unsigned char *MatcherTable, unsigned &MatcherIndex,
SDValue N) {
int64_t Val = MatcherTable[MatcherIndex++];
if (Val & 128)
Val = GetVBR(Val, MatcherTable, MatcherIndex);
ConstantSDNode *C = dyn_cast<ConstantSDNode>(N);
return C != 0 && C->getSExtValue() == Val;
}
LLVM_ATTRIBUTE_ALWAYS_INLINE static bool
CheckAndImm(const unsigned char *MatcherTable, unsigned &MatcherIndex,
SDValue N, SelectionDAGISel &SDISel) {
int64_t Val = MatcherTable[MatcherIndex++];
if (Val & 128)
Val = GetVBR(Val, MatcherTable, MatcherIndex);
if (N->getOpcode() != ISD::AND) return false;
ConstantSDNode *C = dyn_cast<ConstantSDNode>(N->getOperand(1));
return C != 0 && SDISel.CheckAndMask(N.getOperand(0), C, Val);
}
LLVM_ATTRIBUTE_ALWAYS_INLINE static bool
CheckOrImm(const unsigned char *MatcherTable, unsigned &MatcherIndex,
SDValue N, SelectionDAGISel &SDISel) {
int64_t Val = MatcherTable[MatcherIndex++];
if (Val & 128)
Val = GetVBR(Val, MatcherTable, MatcherIndex);
if (N->getOpcode() != ISD::OR) return false;
ConstantSDNode *C = dyn_cast<ConstantSDNode>(N->getOperand(1));
return C != 0 && SDISel.CheckOrMask(N.getOperand(0), C, Val);
}
/// IsPredicateKnownToFail - If we know how and can do so without pushing a
/// scope, evaluate the current node. If the current predicate is known to
/// fail, set Result=true and return anything. If the current predicate is
/// known to pass, set Result=false and return the MatcherIndex to continue
/// with. If the current predicate is unknown, set Result=false and return the
/// MatcherIndex to continue with.
static unsigned IsPredicateKnownToFail(const unsigned char *Table,
unsigned Index, SDValue N,
bool &Result, SelectionDAGISel &SDISel,
SmallVectorImpl<std::pair<SDValue, SDNode*> > &RecordedNodes) {
switch (Table[Index++]) {
default:
Result = false;
return Index-1; // Could not evaluate this predicate.
case SelectionDAGISel::OPC_CheckSame:
Result = !::CheckSame(Table, Index, N, RecordedNodes);
return Index;
case SelectionDAGISel::OPC_CheckPatternPredicate:
Result = !::CheckPatternPredicate(Table, Index, SDISel);
return Index;
case SelectionDAGISel::OPC_CheckPredicate:
Result = !::CheckNodePredicate(Table, Index, SDISel, N.getNode());
return Index;
case SelectionDAGISel::OPC_CheckOpcode:
Result = !::CheckOpcode(Table, Index, N.getNode());
return Index;
case SelectionDAGISel::OPC_CheckType:
Result = !::CheckType(Table, Index, N, SDISel.TLI);
return Index;
case SelectionDAGISel::OPC_CheckChild0Type:
case SelectionDAGISel::OPC_CheckChild1Type:
case SelectionDAGISel::OPC_CheckChild2Type:
case SelectionDAGISel::OPC_CheckChild3Type:
case SelectionDAGISel::OPC_CheckChild4Type:
case SelectionDAGISel::OPC_CheckChild5Type:
case SelectionDAGISel::OPC_CheckChild6Type:
case SelectionDAGISel::OPC_CheckChild7Type:
Result = !::CheckChildType(Table, Index, N, SDISel.TLI,
Table[Index-1] - SelectionDAGISel::OPC_CheckChild0Type);
return Index;
case SelectionDAGISel::OPC_CheckCondCode:
Result = !::CheckCondCode(Table, Index, N);
return Index;
case SelectionDAGISel::OPC_CheckValueType:
Result = !::CheckValueType(Table, Index, N, SDISel.TLI);
return Index;
case SelectionDAGISel::OPC_CheckInteger:
Result = !::CheckInteger(Table, Index, N);
return Index;
case SelectionDAGISel::OPC_CheckAndImm:
Result = !::CheckAndImm(Table, Index, N, SDISel);
return Index;
case SelectionDAGISel::OPC_CheckOrImm:
Result = !::CheckOrImm(Table, Index, N, SDISel);
return Index;
}
}
namespace {
struct MatchScope {
/// FailIndex - If this match fails, this is the index to continue with.
unsigned FailIndex;
/// NodeStack - The node stack when the scope was formed.
SmallVector<SDValue, 4> NodeStack;
/// NumRecordedNodes - The number of recorded nodes when the scope was formed.
unsigned NumRecordedNodes;
/// NumMatchedMemRefs - The number of matched memref entries.
unsigned NumMatchedMemRefs;
/// InputChain/InputGlue - The current chain/glue
SDValue InputChain, InputGlue;
/// HasChainNodesMatched - True if the ChainNodesMatched list is non-empty.
bool HasChainNodesMatched, HasGlueResultNodesMatched;
};
}
SDNode *SelectionDAGISel::
SelectCodeCommon(SDNode *NodeToMatch, const unsigned char *MatcherTable,
unsigned TableSize) {
// FIXME: Should these even be selected? Handle these cases in the caller?
switch (NodeToMatch->getOpcode()) {
default:
break;
case ISD::EntryToken: // These nodes remain the same.
case ISD::BasicBlock:
case ISD::Register:
case ISD::RegisterMask:
//case ISD::VALUETYPE:
//case ISD::CONDCODE:
case ISD::HANDLENODE:
case ISD::MDNODE_SDNODE:
case ISD::TargetConstant:
case ISD::TargetConstantFP:
case ISD::TargetConstantPool:
case ISD::TargetFrameIndex:
case ISD::TargetExternalSymbol:
case ISD::TargetBlockAddress:
case ISD::TargetJumpTable:
case ISD::TargetGlobalTLSAddress:
case ISD::TargetGlobalAddress:
case ISD::TokenFactor:
case ISD::CopyFromReg:
case ISD::CopyToReg:
case ISD::EH_LABEL:
NodeToMatch->setNodeId(-1); // Mark selected.
return 0;
case ISD::AssertSext:
case ISD::AssertZext:
CurDAG->ReplaceAllUsesOfValueWith(SDValue(NodeToMatch, 0),
NodeToMatch->getOperand(0));
return 0;
case ISD::INLINEASM: return Select_INLINEASM(NodeToMatch);
case ISD::UNDEF: return Select_UNDEF(NodeToMatch);
}
assert(!NodeToMatch->isMachineOpcode() && "Node already selected!");
// Set up the node stack with NodeToMatch as the only node on the stack.
SmallVector<SDValue, 8> NodeStack;
SDValue N = SDValue(NodeToMatch, 0);
NodeStack.push_back(N);
// MatchScopes - Scopes used when matching, if a match failure happens, this
// indicates where to continue checking.
SmallVector<MatchScope, 8> MatchScopes;
// RecordedNodes - This is the set of nodes that have been recorded by the
// state machine. The second value is the parent of the node, or null if the
// root is recorded.
SmallVector<std::pair<SDValue, SDNode*>, 8> RecordedNodes;
// MatchedMemRefs - This is the set of MemRef's we've seen in the input
// pattern.
SmallVector<MachineMemOperand*, 2> MatchedMemRefs;
// These are the current input chain and glue for use when generating nodes.
// Various Emit operations change these. For example, emitting a copytoreg
// uses and updates these.
SDValue InputChain, InputGlue;
// ChainNodesMatched - If a pattern matches nodes that have input/output
// chains, the OPC_EmitMergeInputChains operation is emitted which indicates
// which ones they are. The result is captured into this list so that we can
// update the chain results when the pattern is complete.
SmallVector<SDNode*, 3> ChainNodesMatched;
SmallVector<SDNode*, 3> GlueResultNodesMatched;
DEBUG(errs() << "ISEL: Starting pattern match on root node: ";
NodeToMatch->dump(CurDAG);
errs() << '\n');
// Determine where to start the interpreter. Normally we start at opcode #0,
// but if the state machine starts with an OPC_SwitchOpcode, then we
// accelerate the first lookup (which is guaranteed to be hot) with the
// OpcodeOffset table.
unsigned MatcherIndex = 0;
if (!OpcodeOffset.empty()) {
// Already computed the OpcodeOffset table, just index into it.
if (N.getOpcode() < OpcodeOffset.size())
MatcherIndex = OpcodeOffset[N.getOpcode()];
DEBUG(errs() << " Initial Opcode index to " << MatcherIndex << "\n");
} else if (MatcherTable[0] == OPC_SwitchOpcode) {
// Otherwise, the table isn't computed, but the state machine does start
// with an OPC_SwitchOpcode instruction. Populate the table now, since this
// is the first time we're selecting an instruction.
unsigned Idx = 1;
while (1) {
// Get the size of this case.
unsigned CaseSize = MatcherTable[Idx++];
if (CaseSize & 128)
CaseSize = GetVBR(CaseSize, MatcherTable, Idx);
if (CaseSize == 0) break;
// Get the opcode, add the index to the table.
uint16_t Opc = MatcherTable[Idx++];
Opc |= (unsigned short)MatcherTable[Idx++] << 8;
if (Opc >= OpcodeOffset.size())
OpcodeOffset.resize((Opc+1)*2);
OpcodeOffset[Opc] = Idx;
Idx += CaseSize;
}
// Okay, do the lookup for the first opcode.
if (N.getOpcode() < OpcodeOffset.size())
MatcherIndex = OpcodeOffset[N.getOpcode()];
}
while (1) {
assert(MatcherIndex < TableSize && "Invalid index");
#ifndef NDEBUG
unsigned CurrentOpcodeIndex = MatcherIndex;
#endif
BuiltinOpcodes Opcode = (BuiltinOpcodes)MatcherTable[MatcherIndex++];
switch (Opcode) {
case OPC_Scope: {
// Okay, the semantics of this operation are that we should push a scope
// then evaluate the first child. However, pushing a scope only to have
// the first check fail (which then pops it) is inefficient. If we can
// determine immediately that the first check (or first several) will
// immediately fail, don't even bother pushing a scope for them.
unsigned FailIndex;
while (1) {
unsigned NumToSkip = MatcherTable[MatcherIndex++];
if (NumToSkip & 128)
NumToSkip = GetVBR(NumToSkip, MatcherTable, MatcherIndex);
// Found the end of the scope with no match.
if (NumToSkip == 0) {
FailIndex = 0;
break;
}
FailIndex = MatcherIndex+NumToSkip;
unsigned MatcherIndexOfPredicate = MatcherIndex;
(void)MatcherIndexOfPredicate; // silence warning.
// If we can't evaluate this predicate without pushing a scope (e.g. if
// it is a 'MoveParent') or if the predicate succeeds on this node, we
// push the scope and evaluate the full predicate chain.
bool Result;
MatcherIndex = IsPredicateKnownToFail(MatcherTable, MatcherIndex, N,
Result, *this, RecordedNodes);
if (!Result)
break;
DEBUG(errs() << " Skipped scope entry (due to false predicate) at "
<< "index " << MatcherIndexOfPredicate
<< ", continuing at " << FailIndex << "\n");
++NumDAGIselRetries;
// Otherwise, we know that this case of the Scope is guaranteed to fail,
// move to the next case.
MatcherIndex = FailIndex;
}
// If the whole scope failed to match, bail.
if (FailIndex == 0) break;
// Push a MatchScope which indicates where to go if the first child fails
// to match.
MatchScope NewEntry;
NewEntry.FailIndex = FailIndex;
NewEntry.NodeStack.append(NodeStack.begin(), NodeStack.end());
NewEntry.NumRecordedNodes = RecordedNodes.size();
NewEntry.NumMatchedMemRefs = MatchedMemRefs.size();
NewEntry.InputChain = InputChain;
NewEntry.InputGlue = InputGlue;
NewEntry.HasChainNodesMatched = !ChainNodesMatched.empty();
NewEntry.HasGlueResultNodesMatched = !GlueResultNodesMatched.empty();
MatchScopes.push_back(NewEntry);
continue;
}
case OPC_RecordNode: {
// Remember this node, it may end up being an operand in the pattern.
SDNode *Parent = 0;
if (NodeStack.size() > 1)
Parent = NodeStack[NodeStack.size()-2].getNode();
RecordedNodes.push_back(std::make_pair(N, Parent));
continue;
}
case OPC_RecordChild0: case OPC_RecordChild1:
case OPC_RecordChild2: case OPC_RecordChild3:
case OPC_RecordChild4: case OPC_RecordChild5:
case OPC_RecordChild6: case OPC_RecordChild7: {
unsigned ChildNo = Opcode-OPC_RecordChild0;
if (ChildNo >= N.getNumOperands())
break; // Match fails if out of range child #.
RecordedNodes.push_back(std::make_pair(N->getOperand(ChildNo),
N.getNode()));
continue;
}
case OPC_RecordMemRef:
MatchedMemRefs.push_back(cast<MemSDNode>(N)->getMemOperand());
continue;
case OPC_CaptureGlueInput:
// If the current node has an input glue, capture it in InputGlue.
if (N->getNumOperands() != 0 &&
N->getOperand(N->getNumOperands()-1).getValueType() == MVT::Glue)
InputGlue = N->getOperand(N->getNumOperands()-1);
continue;
case OPC_MoveChild: {
unsigned ChildNo = MatcherTable[MatcherIndex++];
if (ChildNo >= N.getNumOperands())
break; // Match fails if out of range child #.
N = N.getOperand(ChildNo);
NodeStack.push_back(N);
continue;
}
case OPC_MoveParent:
// Pop the current node off the NodeStack.
NodeStack.pop_back();
assert(!NodeStack.empty() && "Node stack imbalance!");
N = NodeStack.back();
continue;
case OPC_CheckSame:
if (!::CheckSame(MatcherTable, MatcherIndex, N, RecordedNodes)) break;
continue;
case OPC_CheckPatternPredicate:
if (!::CheckPatternPredicate(MatcherTable, MatcherIndex, *this)) break;
continue;
case OPC_CheckPredicate:
if (!::CheckNodePredicate(MatcherTable, MatcherIndex, *this,
N.getNode()))
break;
continue;
case OPC_CheckComplexPat: {
unsigned CPNum = MatcherTable[MatcherIndex++];
unsigned RecNo = MatcherTable[MatcherIndex++];
assert(RecNo < RecordedNodes.size() && "Invalid CheckComplexPat");
if (!CheckComplexPattern(NodeToMatch, RecordedNodes[RecNo].second,
RecordedNodes[RecNo].first, CPNum,
RecordedNodes))
break;
continue;
}
case OPC_CheckOpcode:
if (!::CheckOpcode(MatcherTable, MatcherIndex, N.getNode())) break;
continue;
case OPC_CheckType:
if (!::CheckType(MatcherTable, MatcherIndex, N, TLI)) break;
continue;
case OPC_SwitchOpcode: {
unsigned CurNodeOpcode = N.getOpcode();
unsigned SwitchStart = MatcherIndex-1; (void)SwitchStart;
unsigned CaseSize;
while (1) {
// Get the size of this case.
CaseSize = MatcherTable[MatcherIndex++];
if (CaseSize & 128)
CaseSize = GetVBR(CaseSize, MatcherTable, MatcherIndex);
if (CaseSize == 0) break;
uint16_t Opc = MatcherTable[MatcherIndex++];
Opc |= (unsigned short)MatcherTable[MatcherIndex++] << 8;
// If the opcode matches, then we will execute this case.
if (CurNodeOpcode == Opc)
break;
// Otherwise, skip over this case.
MatcherIndex += CaseSize;
}
// If no cases matched, bail out.
if (CaseSize == 0) break;
// Otherwise, execute the case we found.
DEBUG(errs() << " OpcodeSwitch from " << SwitchStart
<< " to " << MatcherIndex << "\n");
continue;
}
case OPC_SwitchType: {
MVT CurNodeVT = N.getValueType().getSimpleVT();
unsigned SwitchStart = MatcherIndex-1; (void)SwitchStart;
unsigned CaseSize;
while (1) {
// Get the size of this case.
CaseSize = MatcherTable[MatcherIndex++];
if (CaseSize & 128)
CaseSize = GetVBR(CaseSize, MatcherTable, MatcherIndex);
if (CaseSize == 0) break;
MVT CaseVT = (MVT::SimpleValueType)MatcherTable[MatcherIndex++];
if (CaseVT == MVT::iPTR)
CaseVT = TLI.getPointerTy();
// If the VT matches, then we will execute this case.
if (CurNodeVT == CaseVT)
break;
// Otherwise, skip over this case.
MatcherIndex += CaseSize;
}
// If no cases matched, bail out.
if (CaseSize == 0) break;
// Otherwise, execute the case we found.
DEBUG(errs() << " TypeSwitch[" << EVT(CurNodeVT).getEVTString()
<< "] from " << SwitchStart << " to " << MatcherIndex<<'\n');
continue;
}
case OPC_CheckChild0Type: case OPC_CheckChild1Type:
case OPC_CheckChild2Type: case OPC_CheckChild3Type:
case OPC_CheckChild4Type: case OPC_CheckChild5Type:
case OPC_CheckChild6Type: case OPC_CheckChild7Type:
if (!::CheckChildType(MatcherTable, MatcherIndex, N, TLI,
Opcode-OPC_CheckChild0Type))
break;
continue;
case OPC_CheckCondCode:
if (!::CheckCondCode(MatcherTable, MatcherIndex, N)) break;
continue;
case OPC_CheckValueType:
if (!::CheckValueType(MatcherTable, MatcherIndex, N, TLI)) break;
continue;
case OPC_CheckInteger:
if (!::CheckInteger(MatcherTable, MatcherIndex, N)) break;
continue;
case OPC_CheckAndImm:
if (!::CheckAndImm(MatcherTable, MatcherIndex, N, *this)) break;
continue;
case OPC_CheckOrImm:
if (!::CheckOrImm(MatcherTable, MatcherIndex, N, *this)) break;
continue;
case OPC_CheckFoldableChainNode: {
assert(NodeStack.size() != 1 && "No parent node");
// Verify that all intermediate nodes between the root and this one have
// a single use.
bool HasMultipleUses = false;
for (unsigned i = 1, e = NodeStack.size()-1; i != e; ++i)
if (!NodeStack[i].hasOneUse()) {
HasMultipleUses = true;
break;
}
if (HasMultipleUses) break;
// Check to see that the target thinks this is profitable to fold and that
// we can fold it without inducing cycles in the graph.
if (!IsProfitableToFold(N, NodeStack[NodeStack.size()-2].getNode(),
NodeToMatch) ||
!IsLegalToFold(N, NodeStack[NodeStack.size()-2].getNode(),
NodeToMatch, OptLevel,
true/*We validate our own chains*/))
break;
continue;
}
case OPC_EmitInteger: {
MVT::SimpleValueType VT =
(MVT::SimpleValueType)MatcherTable[MatcherIndex++];
int64_t Val = MatcherTable[MatcherIndex++];
if (Val & 128)
Val = GetVBR(Val, MatcherTable, MatcherIndex);
RecordedNodes.push_back(std::pair<SDValue, SDNode*>(
CurDAG->getTargetConstant(Val, VT), (SDNode*)0));
continue;
}
case OPC_EmitRegister: {
MVT::SimpleValueType VT =
(MVT::SimpleValueType)MatcherTable[MatcherIndex++];
unsigned RegNo = MatcherTable[MatcherIndex++];
RecordedNodes.push_back(std::pair<SDValue, SDNode*>(
CurDAG->getRegister(RegNo, VT), (SDNode*)0));
continue;
}
case OPC_EmitRegister2: {
// For targets w/ more than 256 register names, the register enum
// values are stored in two bytes in the matcher table (just like
// opcodes).
MVT::SimpleValueType VT =
(MVT::SimpleValueType)MatcherTable[MatcherIndex++];
unsigned RegNo = MatcherTable[MatcherIndex++];
RegNo |= MatcherTable[MatcherIndex++] << 8;
RecordedNodes.push_back(std::pair<SDValue, SDNode*>(
CurDAG->getRegister(RegNo, VT), (SDNode*)0));
continue;
}
case OPC_EmitConvertToTarget: {
// Convert from IMM/FPIMM to target version.
unsigned RecNo = MatcherTable[MatcherIndex++];
assert(RecNo < RecordedNodes.size() && "Invalid CheckSame");
SDValue Imm = RecordedNodes[RecNo].first;
if (Imm->getOpcode() == ISD::Constant) {
int64_t Val = cast<ConstantSDNode>(Imm)->getZExtValue();
Imm = CurDAG->getTargetConstant(Val, Imm.getValueType());
} else if (Imm->getOpcode() == ISD::ConstantFP) {
const ConstantFP *Val=cast<ConstantFPSDNode>(Imm)->getConstantFPValue();
Imm = CurDAG->getTargetConstantFP(*Val, Imm.getValueType());
}
RecordedNodes.push_back(std::make_pair(Imm, RecordedNodes[RecNo].second));
continue;
}
case OPC_EmitMergeInputChains1_0: // OPC_EmitMergeInputChains, 1, 0
case OPC_EmitMergeInputChains1_1: { // OPC_EmitMergeInputChains, 1, 1
// These are space-optimized forms of OPC_EmitMergeInputChains.
assert(InputChain.getNode() == 0 &&
"EmitMergeInputChains should be the first chain producing node");
assert(ChainNodesMatched.empty() &&
"Should only have one EmitMergeInputChains per match");
// Read all of the chained nodes.
unsigned RecNo = Opcode == OPC_EmitMergeInputChains1_1;
assert(RecNo < RecordedNodes.size() && "Invalid CheckSame");
ChainNodesMatched.push_back(RecordedNodes[RecNo].first.getNode());
// FIXME: What if other value results of the node have uses not matched
// by this pattern?
if (ChainNodesMatched.back() != NodeToMatch &&
!RecordedNodes[RecNo].first.hasOneUse()) {
ChainNodesMatched.clear();
break;
}
// Merge the input chains if they are not intra-pattern references.
InputChain = HandleMergeInputChains(ChainNodesMatched, CurDAG);
if (InputChain.getNode() == 0)
break; // Failed to merge.
continue;
}
case OPC_EmitMergeInputChains: {
assert(InputChain.getNode() == 0 &&
"EmitMergeInputChains should be the first chain producing node");
// This node gets a list of nodes we matched in the input that have
// chains. We want to token factor all of the input chains to these nodes
// together. However, if any of the input chains is actually one of the
// nodes matched in this pattern, then we have an intra-match reference.
// Ignore these because the newly token factored chain should not refer to
// the old nodes.
unsigned NumChains = MatcherTable[MatcherIndex++];
assert(NumChains != 0 && "Can't TF zero chains");
assert(ChainNodesMatched.empty() &&
"Should only have one EmitMergeInputChains per match");
// Read all of the chained nodes.
for (unsigned i = 0; i != NumChains; ++i) {
unsigned RecNo = MatcherTable[MatcherIndex++];
assert(RecNo < RecordedNodes.size() && "Invalid CheckSame");
ChainNodesMatched.push_back(RecordedNodes[RecNo].first.getNode());
// FIXME: What if other value results of the node have uses not matched
// by this pattern?
if (ChainNodesMatched.back() != NodeToMatch &&
!RecordedNodes[RecNo].first.hasOneUse()) {
ChainNodesMatched.clear();
break;
}
}
// If the inner loop broke out, the match fails.
if (ChainNodesMatched.empty())
break;
// Merge the input chains if they are not intra-pattern references.
InputChain = HandleMergeInputChains(ChainNodesMatched, CurDAG);
if (InputChain.getNode() == 0)
break; // Failed to merge.
continue;
}
case OPC_EmitCopyToReg: {
unsigned RecNo = MatcherTable[MatcherIndex++];
assert(RecNo < RecordedNodes.size() && "Invalid CheckSame");
unsigned DestPhysReg = MatcherTable[MatcherIndex++];
if (InputChain.getNode() == 0)
InputChain = CurDAG->getEntryNode();
InputChain = CurDAG->getCopyToReg(InputChain, NodeToMatch->getDebugLoc(),
DestPhysReg, RecordedNodes[RecNo].first,
InputGlue);
InputGlue = InputChain.getValue(1);
continue;
}
case OPC_EmitNodeXForm: {
unsigned XFormNo = MatcherTable[MatcherIndex++];
unsigned RecNo = MatcherTable[MatcherIndex++];
assert(RecNo < RecordedNodes.size() && "Invalid CheckSame");
SDValue Res = RunSDNodeXForm(RecordedNodes[RecNo].first, XFormNo);
RecordedNodes.push_back(std::pair<SDValue,SDNode*>(Res, (SDNode*) 0));
continue;
}
case OPC_EmitNode:
case OPC_MorphNodeTo: {
uint16_t TargetOpc = MatcherTable[MatcherIndex++];
TargetOpc |= (unsigned short)MatcherTable[MatcherIndex++] << 8;
unsigned EmitNodeInfo = MatcherTable[MatcherIndex++];
// Get the result VT list.
unsigned NumVTs = MatcherTable[MatcherIndex++];
SmallVector<EVT, 4> VTs;
for (unsigned i = 0; i != NumVTs; ++i) {
MVT::SimpleValueType VT =
(MVT::SimpleValueType)MatcherTable[MatcherIndex++];
if (VT == MVT::iPTR) VT = TLI.getPointerTy().SimpleTy;
VTs.push_back(VT);
}
if (EmitNodeInfo & OPFL_Chain)
VTs.push_back(MVT::Other);
if (EmitNodeInfo & OPFL_GlueOutput)
VTs.push_back(MVT::Glue);
// This is hot code, so optimize the two most common cases of 1 and 2
// results.
SDVTList VTList;
if (VTs.size() == 1)
VTList = CurDAG->getVTList(VTs[0]);
else if (VTs.size() == 2)
VTList = CurDAG->getVTList(VTs[0], VTs[1]);
else
VTList = CurDAG->getVTList(VTs.data(), VTs.size());
// Get the operand list.
unsigned NumOps = MatcherTable[MatcherIndex++];
SmallVector<SDValue, 8> Ops;
for (unsigned i = 0; i != NumOps; ++i) {
unsigned RecNo = MatcherTable[MatcherIndex++];
if (RecNo & 128)
RecNo = GetVBR(RecNo, MatcherTable, MatcherIndex);
assert(RecNo < RecordedNodes.size() && "Invalid EmitNode");
Ops.push_back(RecordedNodes[RecNo].first);
}
// If there are variadic operands to add, handle them now.
if (EmitNodeInfo & OPFL_VariadicInfo) {
// Determine the start index to copy from.
unsigned FirstOpToCopy = getNumFixedFromVariadicInfo(EmitNodeInfo);
FirstOpToCopy += (EmitNodeInfo & OPFL_Chain) ? 1 : 0;
assert(NodeToMatch->getNumOperands() >= FirstOpToCopy &&
"Invalid variadic node");
// Copy all of the variadic operands, not including a potential glue
// input.
for (unsigned i = FirstOpToCopy, e = NodeToMatch->getNumOperands();
i != e; ++i) {
SDValue V = NodeToMatch->getOperand(i);
if (V.getValueType() == MVT::Glue) break;
Ops.push_back(V);
}
}
// If this has chain/glue inputs, add them.
if (EmitNodeInfo & OPFL_Chain)
Ops.push_back(InputChain);
if ((EmitNodeInfo & OPFL_GlueInput) && InputGlue.getNode() != 0)
Ops.push_back(InputGlue);
// Create the node.
SDNode *Res = 0;
if (Opcode != OPC_MorphNodeTo) {
// If this is a normal EmitNode command, just create the new node and
// add the results to the RecordedNodes list.
Res = CurDAG->getMachineNode(TargetOpc, NodeToMatch->getDebugLoc(),
VTList, Ops.data(), Ops.size());
// Add all the non-glue/non-chain results to the RecordedNodes list.
for (unsigned i = 0, e = VTs.size(); i != e; ++i) {
if (VTs[i] == MVT::Other || VTs[i] == MVT::Glue) break;
RecordedNodes.push_back(std::pair<SDValue,SDNode*>(SDValue(Res, i),
(SDNode*) 0));
}
} else {
Res = MorphNode(NodeToMatch, TargetOpc, VTList, Ops.data(), Ops.size(),
EmitNodeInfo);
}
// If the node had chain/glue results, update our notion of the current
// chain and glue.
if (EmitNodeInfo & OPFL_GlueOutput) {
InputGlue = SDValue(Res, VTs.size()-1);
if (EmitNodeInfo & OPFL_Chain)
InputChain = SDValue(Res, VTs.size()-2);
} else if (EmitNodeInfo & OPFL_Chain)
InputChain = SDValue(Res, VTs.size()-1);
// If the OPFL_MemRefs glue is set on this node, slap all of the
// accumulated memrefs onto it.
//
// FIXME: This is vastly incorrect for patterns with multiple outputs
// instructions that access memory and for ComplexPatterns that match
// loads.
if (EmitNodeInfo & OPFL_MemRefs) {
// Only attach load or store memory operands if the generated
// instruction may load or store.
const MCInstrDesc &MCID = TM.getInstrInfo()->get(TargetOpc);
bool mayLoad = MCID.mayLoad();
bool mayStore = MCID.mayStore();
unsigned NumMemRefs = 0;
for (SmallVector<MachineMemOperand*, 2>::const_iterator I =
MatchedMemRefs.begin(), E = MatchedMemRefs.end(); I != E; ++I) {
if ((*I)->isLoad()) {
if (mayLoad)
++NumMemRefs;
} else if ((*I)->isStore()) {
if (mayStore)
++NumMemRefs;
} else {
++NumMemRefs;
}
}
MachineSDNode::mmo_iterator MemRefs =
MF->allocateMemRefsArray(NumMemRefs);
MachineSDNode::mmo_iterator MemRefsPos = MemRefs;
for (SmallVector<MachineMemOperand*, 2>::const_iterator I =
MatchedMemRefs.begin(), E = MatchedMemRefs.end(); I != E; ++I) {
if ((*I)->isLoad()) {
if (mayLoad)
*MemRefsPos++ = *I;
} else if ((*I)->isStore()) {
if (mayStore)
*MemRefsPos++ = *I;
} else {
*MemRefsPos++ = *I;
}
}
cast<MachineSDNode>(Res)
->setMemRefs(MemRefs, MemRefs + NumMemRefs);
}
DEBUG(errs() << " "
<< (Opcode == OPC_MorphNodeTo ? "Morphed" : "Created")
<< " node: "; Res->dump(CurDAG); errs() << "\n");
// If this was a MorphNodeTo then we're completely done!
if (Opcode == OPC_MorphNodeTo) {
// Update chain and glue uses.
UpdateChainsAndGlue(NodeToMatch, InputChain, ChainNodesMatched,
InputGlue, GlueResultNodesMatched, true);
return Res;
}
continue;
}
case OPC_MarkGlueResults: {
unsigned NumNodes = MatcherTable[MatcherIndex++];
// Read and remember all the glue-result nodes.
for (unsigned i = 0; i != NumNodes; ++i) {
unsigned RecNo = MatcherTable[MatcherIndex++];
if (RecNo & 128)
RecNo = GetVBR(RecNo, MatcherTable, MatcherIndex);
assert(RecNo < RecordedNodes.size() && "Invalid CheckSame");
GlueResultNodesMatched.push_back(RecordedNodes[RecNo].first.getNode());
}
continue;
}
case OPC_CompleteMatch: {
// The match has been completed, and any new nodes (if any) have been
// created. Patch up references to the matched dag to use the newly
// created nodes.
unsigned NumResults = MatcherTable[MatcherIndex++];
for (unsigned i = 0; i != NumResults; ++i) {
unsigned ResSlot = MatcherTable[MatcherIndex++];
if (ResSlot & 128)
ResSlot = GetVBR(ResSlot, MatcherTable, MatcherIndex);
assert(ResSlot < RecordedNodes.size() && "Invalid CheckSame");
SDValue Res = RecordedNodes[ResSlot].first;
assert(i < NodeToMatch->getNumValues() &&
NodeToMatch->getValueType(i) != MVT::Other &&
NodeToMatch->getValueType(i) != MVT::Glue &&
"Invalid number of results to complete!");
assert((NodeToMatch->getValueType(i) == Res.getValueType() ||
NodeToMatch->getValueType(i) == MVT::iPTR ||
Res.getValueType() == MVT::iPTR ||
NodeToMatch->getValueType(i).getSizeInBits() ==
Res.getValueType().getSizeInBits()) &&
"invalid replacement");
CurDAG->ReplaceAllUsesOfValueWith(SDValue(NodeToMatch, i), Res);
}
// If the root node defines glue, add it to the glue nodes to update list.
if (NodeToMatch->getValueType(NodeToMatch->getNumValues()-1) == MVT::Glue)
GlueResultNodesMatched.push_back(NodeToMatch);
// Update chain and glue uses.
UpdateChainsAndGlue(NodeToMatch, InputChain, ChainNodesMatched,
InputGlue, GlueResultNodesMatched, false);
assert(NodeToMatch->use_empty() &&
"Didn't replace all uses of the node?");
// FIXME: We just return here, which interacts correctly with SelectRoot
// above. We should fix this to not return an SDNode* anymore.
return 0;
}
}
// If the code reached this point, then the match failed. See if there is
// another child to try in the current 'Scope', otherwise pop it until we
// find a case to check.
DEBUG(errs() << " Match failed at index " << CurrentOpcodeIndex << "\n");
++NumDAGIselRetries;
while (1) {
if (MatchScopes.empty()) {
CannotYetSelect(NodeToMatch);
return 0;
}
// Restore the interpreter state back to the point where the scope was
// formed.
MatchScope &LastScope = MatchScopes.back();
RecordedNodes.resize(LastScope.NumRecordedNodes);
NodeStack.clear();
NodeStack.append(LastScope.NodeStack.begin(), LastScope.NodeStack.end());
N = NodeStack.back();
if (LastScope.NumMatchedMemRefs != MatchedMemRefs.size())
MatchedMemRefs.resize(LastScope.NumMatchedMemRefs);
MatcherIndex = LastScope.FailIndex;
DEBUG(errs() << " Continuing at " << MatcherIndex << "\n");
InputChain = LastScope.InputChain;
InputGlue = LastScope.InputGlue;
if (!LastScope.HasChainNodesMatched)
ChainNodesMatched.clear();
if (!LastScope.HasGlueResultNodesMatched)
GlueResultNodesMatched.clear();
// Check to see what the offset is at the new MatcherIndex. If it is zero
// we have reached the end of this scope, otherwise we have another child
// in the current scope to try.
unsigned NumToSkip = MatcherTable[MatcherIndex++];
if (NumToSkip & 128)
NumToSkip = GetVBR(NumToSkip, MatcherTable, MatcherIndex);
// If we have another child in this scope to match, update FailIndex and
// try it.
if (NumToSkip != 0) {
LastScope.FailIndex = MatcherIndex+NumToSkip;
break;
}
// End of this scope, pop it and try the next child in the containing
// scope.
MatchScopes.pop_back();
}
}
}
void SelectionDAGISel::CannotYetSelect(SDNode *N) {
std::string msg;
raw_string_ostream Msg(msg);
Msg << "Cannot select: ";
if (N->getOpcode() != ISD::INTRINSIC_W_CHAIN &&
N->getOpcode() != ISD::INTRINSIC_WO_CHAIN &&
N->getOpcode() != ISD::INTRINSIC_VOID) {
N->printrFull(Msg, CurDAG);
} else {
bool HasInputChain = N->getOperand(0).getValueType() == MVT::Other;
unsigned iid =
cast<ConstantSDNode>(N->getOperand(HasInputChain))->getZExtValue();
if (iid < Intrinsic::num_intrinsics)
Msg << "intrinsic %" << Intrinsic::getName((Intrinsic::ID)iid);
else if (const TargetIntrinsicInfo *TII = TM.getIntrinsicInfo())
Msg << "target intrinsic %" << TII->getName(iid);
else
Msg << "unknown intrinsic #" << iid;
}
report_fatal_error(Msg.str());
}
char SelectionDAGISel::ID = 0;
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