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//===-- LegalizeTypes.cpp - Common code for DAG type legalizer ------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the SelectionDAG::LegalizeTypes method. It transforms
// an arbitrary well-formed SelectionDAG to only consist of legal types. This
// is common code shared among the LegalizeTypes*.cpp files.
//
//===----------------------------------------------------------------------===//
#include "LegalizeTypes.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
#define DEBUG_TYPE "legalize-types"
static cl::opt<bool>
EnableExpensiveChecks("enable-legalize-types-checking", cl::Hidden);
/// Do extensive, expensive, basic correctness checking.
void DAGTypeLegalizer::PerformExpensiveChecks() {
// If a node is not processed, then none of its values should be mapped by any
// of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues.
// If a node is processed, then each value with an illegal type must be mapped
// by exactly one of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues.
// Values with a legal type may be mapped by ReplacedValues, but not by any of
// the other maps.
// Note that these invariants may not hold momentarily when processing a node:
// the node being processed may be put in a map before being marked Processed.
// Note that it is possible to have nodes marked NewNode in the DAG. This can
// occur in two ways. Firstly, a node may be created during legalization but
// never passed to the legalization core. This is usually due to the implicit
// folding that occurs when using the DAG.getNode operators. Secondly, a new
// node may be passed to the legalization core, but when analyzed may morph
// into a different node, leaving the original node as a NewNode in the DAG.
// A node may morph if one of its operands changes during analysis. Whether
// it actually morphs or not depends on whether, after updating its operands,
// it is equivalent to an existing node: if so, it morphs into that existing
// node (CSE). An operand can change during analysis if the operand is a new
// node that morphs, or it is a processed value that was mapped to some other
// value (as recorded in ReplacedValues) in which case the operand is turned
// into that other value. If a node morphs then the node it morphed into will
// be used instead of it for legalization, however the original node continues
// to live on in the DAG.
// The conclusion is that though there may be nodes marked NewNode in the DAG,
// all uses of such nodes are also marked NewNode: the result is a fungus of
// NewNodes growing on top of the useful nodes, and perhaps using them, but
// not used by them.
// If a value is mapped by ReplacedValues, then it must have no uses, except
// by nodes marked NewNode (see above).
// The final node obtained by mapping by ReplacedValues is not marked NewNode.
// Note that ReplacedValues should be applied iteratively.
// Note that the ReplacedValues map may also map deleted nodes (by iterating
// over the DAG we never dereference deleted nodes). This means that it may
// also map nodes marked NewNode if the deallocated memory was reallocated as
// another node, and that new node was not seen by the LegalizeTypes machinery
// (for example because it was created but not used). In general, we cannot
// distinguish between new nodes and deleted nodes.
SmallVector<SDNode*, 16> NewNodes;
for (SDNode &Node : DAG.allnodes()) {
// Remember nodes marked NewNode - they are subject to extra checking below.
if (Node.getNodeId() == NewNode)
NewNodes.push_back(&Node);
for (unsigned i = 0, e = Node.getNumValues(); i != e; ++i) {
SDValue Res(&Node, i);
bool Failed = false;
// Don't create a value in map.
auto ResId = ValueToIdMap.lookup(Res);
unsigned Mapped = 0;
if (ResId) {
auto I = ReplacedValues.find(ResId);
if (I != ReplacedValues.end()) {
Mapped |= 1;
// Check that remapped values are only used by nodes marked NewNode.
for (SDNode::use_iterator UI = Node.use_begin(), UE = Node.use_end();
UI != UE; ++UI)
if (UI.getUse().getResNo() == i)
assert(UI->getNodeId() == NewNode &&
"Remapped value has non-trivial use!");
// Check that the final result of applying ReplacedValues is not
// marked NewNode.
auto NewValId = I->second;
I = ReplacedValues.find(NewValId);
while (I != ReplacedValues.end()) {
NewValId = I->second;
I = ReplacedValues.find(NewValId);
}
SDValue NewVal = getSDValue(NewValId);
(void)NewVal;
assert(NewVal.getNode()->getNodeId() != NewNode &&
"ReplacedValues maps to a new node!");
}
if (PromotedIntegers.count(ResId))
Mapped |= 2;
if (SoftenedFloats.count(ResId))
Mapped |= 4;
if (ScalarizedVectors.count(ResId))
Mapped |= 8;
if (ExpandedIntegers.count(ResId))
Mapped |= 16;
if (ExpandedFloats.count(ResId))
Mapped |= 32;
if (SplitVectors.count(ResId))
Mapped |= 64;
if (WidenedVectors.count(ResId))
Mapped |= 128;
if (PromotedFloats.count(ResId))
Mapped |= 256;
if (SoftPromotedHalfs.count(ResId))
Mapped |= 512;
}
if (Node.getNodeId() != Processed) {
// Since we allow ReplacedValues to map deleted nodes, it may map nodes
// marked NewNode too, since a deleted node may have been reallocated as
// another node that has not been seen by the LegalizeTypes machinery.
if ((Node.getNodeId() == NewNode && Mapped > 1) ||
(Node.getNodeId() != NewNode && Mapped != 0)) {
dbgs() << "Unprocessed value in a map!";
Failed = true;
}
} else if (isTypeLegal(Res.getValueType()) || IgnoreNodeResults(&Node)) {
if (Mapped > 1) {
dbgs() << "Value with legal type was transformed!";
Failed = true;
}
} else {
if (Mapped == 0) {
SDValue NodeById = IdToValueMap.lookup(ResId);
// It is possible the node has been remapped to another node and had
// its Id updated in the Value to Id table. The node it remapped to
// may not have been processed yet. Look up the Id in the Id to Value
// table and re-check the Processed state. If the node hasn't been
// remapped we'll get the same state as we got earlier.
if (NodeById->getNodeId() == Processed) {
dbgs() << "Processed value not in any map!";
Failed = true;
}
} else if (Mapped & (Mapped - 1)) {
dbgs() << "Value in multiple maps!";
Failed = true;
}
}
if (Failed) {
if (Mapped & 1)
dbgs() << " ReplacedValues";
if (Mapped & 2)
dbgs() << " PromotedIntegers";
if (Mapped & 4)
dbgs() << " SoftenedFloats";
if (Mapped & 8)
dbgs() << " ScalarizedVectors";
if (Mapped & 16)
dbgs() << " ExpandedIntegers";
if (Mapped & 32)
dbgs() << " ExpandedFloats";
if (Mapped & 64)
dbgs() << " SplitVectors";
if (Mapped & 128)
dbgs() << " WidenedVectors";
if (Mapped & 256)
dbgs() << " PromotedFloats";
if (Mapped & 512)
dbgs() << " SoftPromoteHalfs";
dbgs() << "\n";
llvm_unreachable(nullptr);
}
}
}
#ifndef NDEBUG
// Checked that NewNodes are only used by other NewNodes.
for (unsigned i = 0, e = NewNodes.size(); i != e; ++i) {
SDNode *N = NewNodes[i];
for (SDNode *U : N->uses())
assert(U->getNodeId() == NewNode && "NewNode used by non-NewNode!");
}
#endif
}
/// This is the main entry point for the type legalizer. This does a top-down
/// traversal of the dag, legalizing types as it goes. Returns "true" if it made
/// any changes.
bool DAGTypeLegalizer::run() {
bool Changed = false;
// 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(DAG.getRoot());
Dummy.setNodeId(Unanalyzed);
// The root of the dag may dangle to deleted nodes until the type legalizer is
// done. Set it to null to avoid confusion.
DAG.setRoot(SDValue());
// Walk all nodes in the graph, assigning them a NodeId of 'ReadyToProcess'
// (and remembering them) if they are leaves and assigning 'Unanalyzed' if
// non-leaves.
for (SDNode &Node : DAG.allnodes()) {
if (Node.getNumOperands() == 0) {
Node.setNodeId(ReadyToProcess);
Worklist.push_back(&Node);
} else {
Node.setNodeId(Unanalyzed);
}
}
// Now that we have a set of nodes to process, handle them all.
while (!Worklist.empty()) {
#ifndef EXPENSIVE_CHECKS
if (EnableExpensiveChecks)
#endif
PerformExpensiveChecks();
SDNode *N = Worklist.pop_back_val();
assert(N->getNodeId() == ReadyToProcess &&
"Node should be ready if on worklist!");
LLVM_DEBUG(dbgs() << "\nLegalizing node: "; N->dump(&DAG));
if (IgnoreNodeResults(N)) {
LLVM_DEBUG(dbgs() << "Ignoring node results\n");
goto ScanOperands;
}
// Scan the values produced by the node, checking to see if any result
// types are illegal.
for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) {
EVT ResultVT = N->getValueType(i);
LLVM_DEBUG(dbgs() << "Analyzing result type: " << ResultVT << "\n");
switch (getTypeAction(ResultVT)) {
case TargetLowering::TypeLegal:
LLVM_DEBUG(dbgs() << "Legal result type\n");
break;
case TargetLowering::TypeScalarizeScalableVector:
report_fatal_error(
"Scalarization of scalable vectors is not supported.");
// The following calls must take care of *all* of the node's results,
// not just the illegal result they were passed (this includes results
// with a legal type). Results can be remapped using ReplaceValueWith,
// or their promoted/expanded/etc values registered in PromotedIntegers,
// ExpandedIntegers etc.
case TargetLowering::TypePromoteInteger:
PromoteIntegerResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypeExpandInteger:
ExpandIntegerResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypeSoftenFloat:
SoftenFloatResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypeExpandFloat:
ExpandFloatResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypeScalarizeVector:
ScalarizeVectorResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypeSplitVector:
SplitVectorResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypeWidenVector:
WidenVectorResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypePromoteFloat:
PromoteFloatResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypeSoftPromoteHalf:
SoftPromoteHalfResult(N, i);
Changed = true;
goto NodeDone;
}
}
ScanOperands:
// Scan the operand list for the node, handling any nodes with operands that
// are illegal.
{
unsigned NumOperands = N->getNumOperands();
bool NeedsReanalyzing = false;
unsigned i;
for (i = 0; i != NumOperands; ++i) {
if (IgnoreNodeResults(N->getOperand(i).getNode()))
continue;
const auto &Op = N->getOperand(i);
LLVM_DEBUG(dbgs() << "Analyzing operand: "; Op.dump(&DAG));
EVT OpVT = Op.getValueType();
switch (getTypeAction(OpVT)) {
case TargetLowering::TypeLegal:
LLVM_DEBUG(dbgs() << "Legal operand\n");
continue;
case TargetLowering::TypeScalarizeScalableVector:
report_fatal_error(
"Scalarization of scalable vectors is not supported.");
// The following calls must either replace all of the node's results
// using ReplaceValueWith, and return "false"; or update the node's
// operands in place, and return "true".
case TargetLowering::TypePromoteInteger:
NeedsReanalyzing = PromoteIntegerOperand(N, i);
Changed = true;
break;
case TargetLowering::TypeExpandInteger:
NeedsReanalyzing = ExpandIntegerOperand(N, i);
Changed = true;
break;
case TargetLowering::TypeSoftenFloat:
NeedsReanalyzing = SoftenFloatOperand(N, i);
Changed = true;
break;
case TargetLowering::TypeExpandFloat:
NeedsReanalyzing = ExpandFloatOperand(N, i);
Changed = true;
break;
case TargetLowering::TypeScalarizeVector:
NeedsReanalyzing = ScalarizeVectorOperand(N, i);
Changed = true;
break;
case TargetLowering::TypeSplitVector:
NeedsReanalyzing = SplitVectorOperand(N, i);
Changed = true;
break;
case TargetLowering::TypeWidenVector:
NeedsReanalyzing = WidenVectorOperand(N, i);
Changed = true;
break;
case TargetLowering::TypePromoteFloat:
NeedsReanalyzing = PromoteFloatOperand(N, i);
Changed = true;
break;
case TargetLowering::TypeSoftPromoteHalf:
NeedsReanalyzing = SoftPromoteHalfOperand(N, i);
Changed = true;
break;
}
break;
}
// The sub-method updated N in place. Check to see if any operands are new,
// and if so, mark them. If the node needs revisiting, don't add all users
// to the worklist etc.
if (NeedsReanalyzing) {
assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?");
N->setNodeId(NewNode);
// Recompute the NodeId and correct processed operands, adding the node to
// the worklist if ready.
SDNode *M = AnalyzeNewNode(N);
if (M == N)
// The node didn't morph - nothing special to do, it will be revisited.
continue;
// The node morphed - this is equivalent to legalizing by replacing every
// value of N with the corresponding value of M. So do that now.
assert(N->getNumValues() == M->getNumValues() &&
"Node morphing changed the number of results!");
for (unsigned i = 0, e = N->getNumValues(); i != e; ++i)
// Replacing the value takes care of remapping the new value.
ReplaceValueWith(SDValue(N, i), SDValue(M, i));
assert(N->getNodeId() == NewNode && "Unexpected node state!");
// The node continues to live on as part of the NewNode fungus that
// grows on top of the useful nodes. Nothing more needs to be done
// with it - move on to the next node.
continue;
}
if (i == NumOperands) {
LLVM_DEBUG(dbgs() << "Legally typed node: "; N->dump(&DAG));
}
}
NodeDone:
// If we reach here, the node was processed, potentially creating new nodes.
// Mark it as processed and add its users to the worklist as appropriate.
assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?");
N->setNodeId(Processed);
for (SDNode *User : N->uses()) {
int NodeId = User->getNodeId();
// This node has two options: it can either be a new node or its Node ID
// may be a count of the number of operands it has that are not ready.
if (NodeId > 0) {
User->setNodeId(NodeId-1);
// If this was the last use it was waiting on, add it to the ready list.
if (NodeId-1 == ReadyToProcess)
Worklist.push_back(User);
continue;
}
// If this is an unreachable new node, then ignore it. If it ever becomes
// reachable by being used by a newly created node then it will be handled
// by AnalyzeNewNode.
if (NodeId == NewNode)
continue;
// Otherwise, this node is new: this is the first operand of it that
// became ready. Its new NodeId is the number of operands it has minus 1
// (as this node is now processed).
assert(NodeId == Unanalyzed && "Unknown node ID!");
User->setNodeId(User->getNumOperands() - 1);
// If the node only has a single operand, it is now ready.
if (User->getNumOperands() == 1)
Worklist.push_back(User);
}
}
#ifndef EXPENSIVE_CHECKS
if (EnableExpensiveChecks)
#endif
PerformExpensiveChecks();
// If the root changed (e.g. it was a dead load) update the root.
DAG.setRoot(Dummy.getValue());
// Remove dead nodes. This is important to do for cleanliness but also before
// the checking loop below. Implicit folding by the DAG.getNode operators and
// node morphing can cause unreachable nodes to be around with their flags set
// to new.
DAG.RemoveDeadNodes();
// In a debug build, scan all the nodes to make sure we found them all. This
// ensures that there are no cycles and that everything got processed.
#ifndef NDEBUG
for (SDNode &Node : DAG.allnodes()) {
bool Failed = false;
// Check that all result types are legal.
if (!IgnoreNodeResults(&Node))
for (unsigned i = 0, NumVals = Node.getNumValues(); i < NumVals; ++i)
if (!isTypeLegal(Node.getValueType(i))) {
dbgs() << "Result type " << i << " illegal: ";
Node.dump(&DAG);
Failed = true;
}
// Check that all operand types are legal.
for (unsigned i = 0, NumOps = Node.getNumOperands(); i < NumOps; ++i)
if (!IgnoreNodeResults(Node.getOperand(i).getNode()) &&
!isTypeLegal(Node.getOperand(i).getValueType())) {
dbgs() << "Operand type " << i << " illegal: ";
Node.getOperand(i).dump(&DAG);
Failed = true;
}
if (Node.getNodeId() != Processed) {
if (Node.getNodeId() == NewNode)
dbgs() << "New node not analyzed?\n";
else if (Node.getNodeId() == Unanalyzed)
dbgs() << "Unanalyzed node not noticed?\n";
else if (Node.getNodeId() > 0)
dbgs() << "Operand not processed?\n";
else if (Node.getNodeId() == ReadyToProcess)
dbgs() << "Not added to worklist?\n";
Failed = true;
}
if (Failed) {
Node.dump(&DAG); dbgs() << "\n";
llvm_unreachable(nullptr);
}
}
#endif
return Changed;
}
/// The specified node is the root of a subtree of potentially new nodes.
/// Correct any processed operands (this may change the node) and calculate the
/// NodeId. If the node itself changes to a processed node, it is not remapped -
/// the caller needs to take care of this. Returns the potentially changed node.
SDNode *DAGTypeLegalizer::AnalyzeNewNode(SDNode *N) {
// If this was an existing node that is already done, we're done.
if (N->getNodeId() != NewNode && N->getNodeId() != Unanalyzed)
return N;
// Okay, we know that this node is new. Recursively walk all of its operands
// to see if they are new also. The depth of this walk is bounded by the size
// of the new tree that was constructed (usually 2-3 nodes), so we don't worry
// about revisiting of nodes.
//
// As we walk the operands, keep track of the number of nodes that are
// processed. If non-zero, this will become the new nodeid of this node.
// Operands may morph when they are analyzed. If so, the node will be
// updated after all operands have been analyzed. Since this is rare,
// the code tries to minimize overhead in the non-morphing case.
std::vector<SDValue> NewOps;
unsigned NumProcessed = 0;
for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
SDValue OrigOp = N->getOperand(i);
SDValue Op = OrigOp;
AnalyzeNewValue(Op); // Op may morph.
if (Op.getNode()->getNodeId() == Processed)
++NumProcessed;
if (!NewOps.empty()) {
// Some previous operand changed. Add this one to the list.
NewOps.push_back(Op);
} else if (Op != OrigOp) {
// This is the first operand to change - add all operands so far.
NewOps.insert(NewOps.end(), N->op_begin(), N->op_begin() + i);
NewOps.push_back(Op);
}
}
// Some operands changed - update the node.
if (!NewOps.empty()) {
SDNode *M = DAG.UpdateNodeOperands(N, NewOps);
if (M != N) {
// The node morphed into a different node. Normally for this to happen
// the original node would have to be marked NewNode. However this can
// in theory momentarily not be the case while ReplaceValueWith is doing
// its stuff. Mark the original node NewNode to help basic correctness
// checking.
N->setNodeId(NewNode);
if (M->getNodeId() != NewNode && M->getNodeId() != Unanalyzed)
// It morphed into a previously analyzed node - nothing more to do.
return M;
// It morphed into a different new node. Do the equivalent of passing
// it to AnalyzeNewNode: expunge it and calculate the NodeId. No need
// to remap the operands, since they are the same as the operands we
// remapped above.
N = M;
}
}
// Calculate the NodeId.
N->setNodeId(N->getNumOperands() - NumProcessed);
if (N->getNodeId() == ReadyToProcess)
Worklist.push_back(N);
return N;
}
/// Call AnalyzeNewNode, updating the node in Val if needed.
/// If the node changes to a processed node, then remap it.
void DAGTypeLegalizer::AnalyzeNewValue(SDValue &Val) {
Val.setNode(AnalyzeNewNode(Val.getNode()));
if (Val.getNode()->getNodeId() == Processed)
// We were passed a processed node, or it morphed into one - remap it.
RemapValue(Val);
}
/// If the specified value was already legalized to another value,
/// replace it by that value.
void DAGTypeLegalizer::RemapValue(SDValue &V) {
auto Id = getTableId(V);
V = getSDValue(Id);
}
void DAGTypeLegalizer::RemapId(TableId &Id) {
auto I = ReplacedValues.find(Id);
if (I != ReplacedValues.end()) {
assert(Id != I->second && "Id is mapped to itself.");
// Use path compression to speed up future lookups if values get multiply
// replaced with other values.
RemapId(I->second);
Id = I->second;
// Note that N = IdToValueMap[Id] it is possible to have
// N.getNode()->getNodeId() == NewNode at this point because it is possible
// for a node to be put in the map before being processed.
}
}
namespace {
/// This class is a DAGUpdateListener that listens for updates to nodes and
/// recomputes their ready state.
class NodeUpdateListener : public SelectionDAG::DAGUpdateListener {
DAGTypeLegalizer &DTL;
SmallSetVector<SDNode*, 16> &NodesToAnalyze;
public:
explicit NodeUpdateListener(DAGTypeLegalizer &dtl,
SmallSetVector<SDNode*, 16> &nta)
: SelectionDAG::DAGUpdateListener(dtl.getDAG()),
DTL(dtl), NodesToAnalyze(nta) {}
void NodeDeleted(SDNode *N, SDNode *E) override {
assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
N->getNodeId() != DAGTypeLegalizer::Processed &&
"Invalid node ID for RAUW deletion!");
// It is possible, though rare, for the deleted node N to occur as a
// target in a map, so note the replacement N -> E in ReplacedValues.
assert(E && "Node not replaced?");
DTL.NoteDeletion(N, E);
// In theory the deleted node could also have been scheduled for analysis.
// So remove it from the set of nodes which will be analyzed.
NodesToAnalyze.remove(N);
// In general nothing needs to be done for E, since it didn't change but
// only gained new uses. However N -> E was just added to ReplacedValues,
// and the result of a ReplacedValues mapping is not allowed to be marked
// NewNode. So if E is marked NewNode, then it needs to be analyzed.
if (E->getNodeId() == DAGTypeLegalizer::NewNode)
NodesToAnalyze.insert(E);
}
void NodeUpdated(SDNode *N) override {
// Node updates can mean pretty much anything. It is possible that an
// operand was set to something already processed (f.e.) in which case
// this node could become ready. Recompute its flags.
assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
N->getNodeId() != DAGTypeLegalizer::Processed &&
"Invalid node ID for RAUW deletion!");
N->setNodeId(DAGTypeLegalizer::NewNode);
NodesToAnalyze.insert(N);
}
};
}
/// The specified value was legalized to the specified other value.
/// Update the DAG and NodeIds replacing any uses of From to use To instead.
void DAGTypeLegalizer::ReplaceValueWith(SDValue From, SDValue To) {
assert(From.getNode() != To.getNode() && "Potential legalization loop!");
// If expansion produced new nodes, make sure they are properly marked.
AnalyzeNewValue(To);
// Anything that used the old node should now use the new one. Note that this
// can potentially cause recursive merging.
SmallSetVector<SDNode*, 16> NodesToAnalyze;
NodeUpdateListener NUL(*this, NodesToAnalyze);
do {
// The old node may be present in a map like ExpandedIntegers or
// PromotedIntegers. Inform maps about the replacement.
auto FromId = getTableId(From);
auto ToId = getTableId(To);
if (FromId != ToId)
ReplacedValues[FromId] = ToId;
DAG.ReplaceAllUsesOfValueWith(From, To);
// Process the list of nodes that need to be reanalyzed.
while (!NodesToAnalyze.empty()) {
SDNode *N = NodesToAnalyze.pop_back_val();
if (N->getNodeId() != DAGTypeLegalizer::NewNode)
// The node was analyzed while reanalyzing an earlier node - it is safe
// to skip. Note that this is not a morphing node - otherwise it would
// still be marked NewNode.
continue;
// Analyze the node's operands and recalculate the node ID.
SDNode *M = AnalyzeNewNode(N);
if (M != N) {
// The node morphed into a different node. Make everyone use the new
// node instead.
assert(M->getNodeId() != NewNode && "Analysis resulted in NewNode!");
assert(N->getNumValues() == M->getNumValues() &&
"Node morphing changed the number of results!");
for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) {
SDValue OldVal(N, i);
SDValue NewVal(M, i);
if (M->getNodeId() == Processed)
RemapValue(NewVal);
// OldVal may be a target of the ReplacedValues map which was marked
// NewNode to force reanalysis because it was updated. Ensure that
// anything that ReplacedValues mapped to OldVal will now be mapped
// all the way to NewVal.
auto OldValId = getTableId(OldVal);
auto NewValId = getTableId(NewVal);
DAG.ReplaceAllUsesOfValueWith(OldVal, NewVal);
if (OldValId != NewValId)
ReplacedValues[OldValId] = NewValId;
}
// The original node continues to exist in the DAG, marked NewNode.
}
}
// When recursively update nodes with new nodes, it is possible to have
// new uses of From due to CSE. If this happens, replace the new uses of
// From with To.
} while (!From.use_empty());
}
void DAGTypeLegalizer::SetPromotedInteger(SDValue Op, SDValue Result) {
assert(Result.getValueType() ==
TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
"Invalid type for promoted integer");
AnalyzeNewValue(Result);
auto &OpIdEntry = PromotedIntegers[getTableId(Op)];
assert((OpIdEntry == 0) && "Node is already promoted!");
OpIdEntry = getTableId(Result);
DAG.transferDbgValues(Op, Result);
}
void DAGTypeLegalizer::SetSoftenedFloat(SDValue Op, SDValue Result) {
#ifndef NDEBUG
EVT VT = Result.getValueType();
LLVMContext &Ctx = *DAG.getContext();
assert((VT == EVT::getIntegerVT(Ctx, 80) ||
VT == TLI.getTypeToTransformTo(Ctx, Op.getValueType())) &&
"Invalid type for softened float");
#endif
AnalyzeNewValue(Result);
auto &OpIdEntry = SoftenedFloats[getTableId(Op)];
assert((OpIdEntry == 0) && "Node is already converted to integer!");
OpIdEntry = getTableId(Result);
}
void DAGTypeLegalizer::SetPromotedFloat(SDValue Op, SDValue Result) {
assert(Result.getValueType() ==
TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
"Invalid type for promoted float");
AnalyzeNewValue(Result);
auto &OpIdEntry = PromotedFloats[getTableId(Op)];
assert((OpIdEntry == 0) && "Node is already promoted!");
OpIdEntry = getTableId(Result);
}
void DAGTypeLegalizer::SetSoftPromotedHalf(SDValue Op, SDValue Result) {
assert(Result.getValueType() == MVT::i16 &&
"Invalid type for soft-promoted half");
AnalyzeNewValue(Result);
auto &OpIdEntry = SoftPromotedHalfs[getTableId(Op)];
assert((OpIdEntry == 0) && "Node is already promoted!");
OpIdEntry = getTableId(Result);
}
void DAGTypeLegalizer::SetScalarizedVector(SDValue Op, SDValue Result) {
// Note that in some cases vector operation operands may be greater than
// the vector element type. For example BUILD_VECTOR of type <1 x i1> with
// a constant i8 operand.
// We don't currently support the scalarization of scalable vector types.
assert(Result.getValueSizeInBits().getFixedValue() >=
Op.getScalarValueSizeInBits() &&
"Invalid type for scalarized vector");
AnalyzeNewValue(Result);
auto &OpIdEntry = ScalarizedVectors[getTableId(Op)];
assert((OpIdEntry == 0) && "Node is already scalarized!");
OpIdEntry = getTableId(Result);
}
void DAGTypeLegalizer::GetExpandedInteger(SDValue Op, SDValue &Lo,
SDValue &Hi) {
std::pair<TableId, TableId> &Entry = ExpandedIntegers[getTableId(Op)];
assert((Entry.first != 0) && "Operand isn't expanded");
Lo = getSDValue(Entry.first);
Hi = getSDValue(Entry.second);
}
void DAGTypeLegalizer::SetExpandedInteger(SDValue Op, SDValue Lo,
SDValue Hi) {
assert(Lo.getValueType() ==
TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
Hi.getValueType() == Lo.getValueType() &&
"Invalid type for expanded integer");
// Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
AnalyzeNewValue(Lo);
AnalyzeNewValue(Hi);
// Transfer debug values. Don't invalidate the source debug value until it's
// been transferred to the high and low bits.
if (DAG.getDataLayout().isBigEndian()) {
DAG.transferDbgValues(Op, Hi, 0, Hi.getValueSizeInBits(), false);
DAG.transferDbgValues(Op, Lo, Hi.getValueSizeInBits(),
Lo.getValueSizeInBits());
} else {
DAG.transferDbgValues(Op, Lo, 0, Lo.getValueSizeInBits(), false);
DAG.transferDbgValues(Op, Hi, Lo.getValueSizeInBits(),
Hi.getValueSizeInBits());
}
// Remember that this is the result of the node.
std::pair<TableId, TableId> &Entry = ExpandedIntegers[getTableId(Op)];
assert((Entry.first == 0) && "Node already expanded");
Entry.first = getTableId(Lo);
Entry.second = getTableId(Hi);
}
void DAGTypeLegalizer::GetExpandedFloat(SDValue Op, SDValue &Lo,
SDValue &Hi) {
std::pair<TableId, TableId> &Entry = ExpandedFloats[getTableId(Op)];
assert((Entry.first != 0) && "Operand isn't expanded");
Lo = getSDValue(Entry.first);
Hi = getSDValue(Entry.second);
}
void DAGTypeLegalizer::SetExpandedFloat(SDValue Op, SDValue Lo,
SDValue Hi) {
assert(Lo.getValueType() ==
TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
Hi.getValueType() == Lo.getValueType() &&
"Invalid type for expanded float");
// Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
AnalyzeNewValue(Lo);
AnalyzeNewValue(Hi);
std::pair<TableId, TableId> &Entry = ExpandedFloats[getTableId(Op)];
assert((Entry.first == 0) && "Node already expanded");
Entry.first = getTableId(Lo);
Entry.second = getTableId(Hi);
}
void DAGTypeLegalizer::GetSplitVector(SDValue Op, SDValue &Lo,
SDValue &Hi) {
std::pair<TableId, TableId> &Entry = SplitVectors[getTableId(Op)];
Lo = getSDValue(Entry.first);
Hi = getSDValue(Entry.second);
assert(Lo.getNode() && "Operand isn't split");
;
}
void DAGTypeLegalizer::SetSplitVector(SDValue Op, SDValue Lo,
SDValue Hi) {
assert(Lo.getValueType().getVectorElementType() ==
Op.getValueType().getVectorElementType() &&
Lo.getValueType().getVectorElementCount() * 2 ==
Op.getValueType().getVectorElementCount() &&
Hi.getValueType() == Lo.getValueType() &&
"Invalid type for split vector");
// Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
AnalyzeNewValue(Lo);
AnalyzeNewValue(Hi);
// Remember that this is the result of the node.
std::pair<TableId, TableId> &Entry = SplitVectors[getTableId(Op)];
assert((Entry.first == 0) && "Node already split");
Entry.first = getTableId(Lo);
Entry.second = getTableId(Hi);
}
void DAGTypeLegalizer::SetWidenedVector(SDValue Op, SDValue Result) {
assert(Result.getValueType() ==
TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
"Invalid type for widened vector");
AnalyzeNewValue(Result);
auto &OpIdEntry = WidenedVectors[getTableId(Op)];
assert((OpIdEntry == 0) && "Node already widened!");
OpIdEntry = getTableId(Result);
}
//===----------------------------------------------------------------------===//
// Utilities.
//===----------------------------------------------------------------------===//
/// Convert to an integer of the same size.
SDValue DAGTypeLegalizer::BitConvertToInteger(SDValue Op) {
unsigned BitWidth = Op.getValueSizeInBits();
return DAG.getNode(ISD::BITCAST, SDLoc(Op),
EVT::getIntegerVT(*DAG.getContext(), BitWidth), Op);
}
/// Convert to a vector of integers of the same size.
SDValue DAGTypeLegalizer::BitConvertVectorToIntegerVector(SDValue Op) {
assert(Op.getValueType().isVector() && "Only applies to vectors!");
unsigned EltWidth = Op.getScalarValueSizeInBits();
EVT EltNVT = EVT::getIntegerVT(*DAG.getContext(), EltWidth);
auto EltCnt = Op.getValueType().getVectorElementCount();
return DAG.getNode(ISD::BITCAST, SDLoc(Op),
EVT::getVectorVT(*DAG.getContext(), EltNVT, EltCnt), Op);
}
SDValue DAGTypeLegalizer::CreateStackStoreLoad(SDValue Op,
EVT DestVT) {
SDLoc dl(Op);
// Create the stack frame object. Make sure it is aligned for both
// the source and destination types.
// In cases where the vector is illegal it will be broken down into parts
// and stored in parts - we should use the alignment for the smallest part.
Align DestAlign = DAG.getReducedAlign(DestVT, /*UseABI=*/false);
Align OpAlign = DAG.getReducedAlign(Op.getValueType(), /*UseABI=*/false);
Align Align = std::max(DestAlign, OpAlign);
SDValue StackPtr =
DAG.CreateStackTemporary(Op.getValueType().getStoreSize(), Align);
// Emit a store to the stack slot.
SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, Op, StackPtr,
MachinePointerInfo(), Align);
// Result is a load from the stack slot.
return DAG.getLoad(DestVT, dl, Store, StackPtr, MachinePointerInfo(), Align);
}
/// Replace the node's results with custom code provided by the target and
/// return "true", or do nothing and return "false".
/// The last parameter is FALSE if we are dealing with a node with legal
/// result types and illegal operand. The second parameter denotes the type of
/// illegal OperandNo in that case.
/// The last parameter being TRUE means we are dealing with a
/// node with illegal result types. The second parameter denotes the type of
/// illegal ResNo in that case.
bool DAGTypeLegalizer::CustomLowerNode(SDNode *N, EVT VT, bool LegalizeResult) {
// See if the target wants to custom lower this node.
if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom)
return false;
SmallVector<SDValue, 8> Results;
if (LegalizeResult)
TLI.ReplaceNodeResults(N, Results, DAG);
else
TLI.LowerOperationWrapper(N, Results, DAG);
if (Results.empty())
// The target didn't want to custom lower it after all.
return false;
// Make everything that once used N's values now use those in Results instead.
assert(Results.size() == N->getNumValues() &&
"Custom lowering returned the wrong number of results!");
for (unsigned i = 0, e = Results.size(); i != e; ++i) {
ReplaceValueWith(SDValue(N, i), Results[i]);
}
return true;
}
/// Widen the node's results with custom code provided by the target and return
/// "true", or do nothing and return "false".
bool DAGTypeLegalizer::CustomWidenLowerNode(SDNode *N, EVT VT) {
// See if the target wants to custom lower this node.
if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom)
return false;
SmallVector<SDValue, 8> Results;
TLI.ReplaceNodeResults(N, Results, DAG);
if (Results.empty())
// The target didn't want to custom widen lower its result after all.
return false;
// Update the widening map.
assert(Results.size() == N->getNumValues() &&
"Custom lowering returned the wrong number of results!");
for (unsigned i = 0, e = Results.size(); i != e; ++i) {
// If this is a chain output or already widened just replace it.
bool WasWidened = SDValue(N, i).getValueType() != Results[i].getValueType();
if (WasWidened)
SetWidenedVector(SDValue(N, i), Results[i]);
else
ReplaceValueWith(SDValue(N, i), Results[i]);
}
return true;
}
SDValue DAGTypeLegalizer::DisintegrateMERGE_VALUES(SDNode *N, unsigned ResNo) {
for (unsigned i = 0, e = N->getNumValues(); i != e; ++i)
if (i != ResNo)
ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i)));
return SDValue(N->getOperand(ResNo));
}
/// Use ISD::EXTRACT_ELEMENT nodes to extract the low and high parts of the
/// given value.
void DAGTypeLegalizer::GetPairElements(SDValue Pair,
SDValue &Lo, SDValue &Hi) {
SDLoc dl(Pair);
EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), Pair.getValueType());
std::tie(Lo, Hi) = DAG.SplitScalar(Pair, dl, NVT, NVT);
}
/// Build an integer with low bits Lo and high bits Hi.
SDValue DAGTypeLegalizer::JoinIntegers(SDValue Lo, SDValue Hi) {
// Arbitrarily use dlHi for result SDLoc
SDLoc dlHi(Hi);
SDLoc dlLo(Lo);
EVT LVT = Lo.getValueType();
EVT HVT = Hi.getValueType();
EVT NVT = EVT::getIntegerVT(*DAG.getContext(),
LVT.getSizeInBits() + HVT.getSizeInBits());
EVT ShiftAmtVT = TLI.getShiftAmountTy(NVT, DAG.getDataLayout());
Lo = DAG.getNode(ISD::ZERO_EXTEND, dlLo, NVT, Lo);
Hi = DAG.getNode(ISD::ANY_EXTEND, dlHi, NVT, Hi);
Hi = DAG.getNode(ISD::SHL, dlHi, NVT, Hi,
DAG.getConstant(LVT.getSizeInBits(), dlHi, ShiftAmtVT));
return DAG.getNode(ISD::OR, dlHi, NVT, Lo, Hi);
}
/// Promote the given target boolean to a target boolean of the given type.
/// A target boolean is an integer value, not necessarily of type i1, the bits
/// of which conform to getBooleanContents.
///
/// ValVT is the type of values that produced the boolean.
SDValue DAGTypeLegalizer::PromoteTargetBoolean(SDValue Bool, EVT ValVT) {
return TLI.promoteTargetBoolean(DAG, Bool, ValVT);
}
/// Return the lower LoVT bits of Op in Lo and the upper HiVT bits in Hi.
void DAGTypeLegalizer::SplitInteger(SDValue Op,
EVT LoVT, EVT HiVT,
SDValue &Lo, SDValue &Hi) {
SDLoc dl(Op);
assert(LoVT.getSizeInBits() + HiVT.getSizeInBits() ==
Op.getValueSizeInBits() && "Invalid integer splitting!");
Lo = DAG.getNode(ISD::TRUNCATE, dl, LoVT, Op);
unsigned ReqShiftAmountInBits =
Log2_32_Ceil(Op.getValueType().getSizeInBits());
MVT ShiftAmountTy =
TLI.getScalarShiftAmountTy(DAG.getDataLayout(), Op.getValueType());
if (ReqShiftAmountInBits > ShiftAmountTy.getSizeInBits())
ShiftAmountTy = MVT::getIntegerVT(NextPowerOf2(ReqShiftAmountInBits));
Hi = DAG.getNode(ISD::SRL, dl, Op.getValueType(), Op,
DAG.getConstant(LoVT.getSizeInBits(), dl, ShiftAmountTy));
Hi = DAG.getNode(ISD::TRUNCATE, dl, HiVT, Hi);
}
/// Return the lower and upper halves of Op's bits in a value type half the
/// size of Op's.
void DAGTypeLegalizer::SplitInteger(SDValue Op,
SDValue &Lo, SDValue &Hi) {
EVT HalfVT =
EVT::getIntegerVT(*DAG.getContext(), Op.getValueSizeInBits() / 2);
SplitInteger(Op, HalfVT, HalfVT, Lo, Hi);
}
//===----------------------------------------------------------------------===//
// Entry Point
//===----------------------------------------------------------------------===//
/// This transforms the SelectionDAG into a SelectionDAG that only uses types
/// natively supported by the target. Returns "true" if it made any changes.
///
/// Note that this is an involved process that may invalidate pointers into
/// the graph.
bool SelectionDAG::LegalizeTypes() {
return DAGTypeLegalizer(*this).run();
}