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llvm-project/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp

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//===- lib/CodeGen/GlobalISel/LegalizerInfo.cpp - 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
//
//===----------------------------------------------------------------------===//
//
// Implement an interface to specify and query how an illegal operation on a
// given type should be expanded.
//
// Issues to be resolved:
// + Make it fast.
// + Support weird types like i3, <7 x i3>, ...
// + Operations with more than one type (ICMP, CMPXCHG, intrinsics, ...)
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
#include "llvm/ADT/SmallBitVector.h"
#include "llvm/CodeGen/GlobalISel/GISelChangeObserver.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetOpcodes.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/LowLevelTypeImpl.h"
#include "llvm/Support/MathExtras.h"
#include <algorithm>
#include <map>
using namespace llvm;
using namespace LegalizeActions;
#define DEBUG_TYPE "legalizer-info"
cl::opt<bool> llvm::DisableGISelLegalityCheck(
"disable-gisel-legality-check",
cl::desc("Don't verify that MIR is fully legal between GlobalISel passes"),
cl::Hidden);
raw_ostream &llvm::operator<<(raw_ostream &OS, LegalizeAction Action) {
switch (Action) {
case Legal:
OS << "Legal";
break;
case NarrowScalar:
OS << "NarrowScalar";
break;
case WidenScalar:
OS << "WidenScalar";
break;
case FewerElements:
OS << "FewerElements";
break;
case MoreElements:
OS << "MoreElements";
break;
case Lower:
OS << "Lower";
break;
case Libcall:
OS << "Libcall";
break;
case Custom:
OS << "Custom";
break;
case Unsupported:
OS << "Unsupported";
break;
case NotFound:
OS << "NotFound";
break;
case UseLegacyRules:
OS << "UseLegacyRules";
break;
}
return OS;
}
raw_ostream &LegalityQuery::print(raw_ostream &OS) const {
OS << Opcode << ", Tys={";
for (const auto &Type : Types) {
OS << Type << ", ";
}
OS << "}, Opcode=";
OS << Opcode << ", MMOs={";
for (const auto &MMODescr : MMODescrs) {
OS << MMODescr.SizeInBits << ", ";
}
OS << "}";
return OS;
}
#ifndef NDEBUG
// Make sure the rule won't (trivially) loop forever.
static bool hasNoSimpleLoops(const LegalizeRule &Rule, const LegalityQuery &Q,
const std::pair<unsigned, LLT> &Mutation) {
switch (Rule.getAction()) {
case Custom:
case Lower:
case MoreElements:
case FewerElements:
break;
default:
return Q.Types[Mutation.first] != Mutation.second;
}
return true;
}
// Make sure the returned mutation makes sense for the match type.
static bool mutationIsSane(const LegalizeRule &Rule,
const LegalityQuery &Q,
std::pair<unsigned, LLT> Mutation) {
// If the user wants a custom mutation, then we can't really say much about
// it. Return true, and trust that they're doing the right thing.
if (Rule.getAction() == Custom)
return true;
const unsigned TypeIdx = Mutation.first;
const LLT OldTy = Q.Types[TypeIdx];
const LLT NewTy = Mutation.second;
switch (Rule.getAction()) {
case FewerElements:
if (!OldTy.isVector())
return false;
LLVM_FALLTHROUGH;
case MoreElements: {
// MoreElements can go from scalar to vector.
const unsigned OldElts = OldTy.isVector() ? OldTy.getNumElements() : 1;
if (NewTy.isVector()) {
if (Rule.getAction() == FewerElements) {
// Make sure the element count really decreased.
if (NewTy.getNumElements() >= OldElts)
return false;
} else {
// Make sure the element count really increased.
if (NewTy.getNumElements() <= OldElts)
return false;
}
}
// Make sure the element type didn't change.
return NewTy.getScalarType() == OldTy.getScalarType();
}
case NarrowScalar:
case WidenScalar: {
if (OldTy.isVector()) {
// Number of elements should not change.
if (!NewTy.isVector() || OldTy.getNumElements() != NewTy.getNumElements())
return false;
} else {
// Both types must be vectors
if (NewTy.isVector())
return false;
}
if (Rule.getAction() == NarrowScalar) {
// Make sure the size really decreased.
if (NewTy.getScalarSizeInBits() >= OldTy.getScalarSizeInBits())
return false;
} else {
// Make sure the size really increased.
if (NewTy.getScalarSizeInBits() <= OldTy.getScalarSizeInBits())
return false;
}
return true;
}
default:
return true;
}
}
#endif
LegalizeActionStep LegalizeRuleSet::apply(const LegalityQuery &Query) const {
LLVM_DEBUG(dbgs() << "Applying legalizer ruleset to: "; Query.print(dbgs());
dbgs() << "\n");
if (Rules.empty()) {
LLVM_DEBUG(dbgs() << ".. fallback to legacy rules (no rules defined)\n");
return {LegalizeAction::UseLegacyRules, 0, LLT{}};
}
for (const LegalizeRule &Rule : Rules) {
if (Rule.match(Query)) {
LLVM_DEBUG(dbgs() << ".. match\n");
std::pair<unsigned, LLT> Mutation = Rule.determineMutation(Query);
LLVM_DEBUG(dbgs() << ".. .. " << Rule.getAction() << ", "
<< Mutation.first << ", " << Mutation.second << "\n");
assert(mutationIsSane(Rule, Query, Mutation) &&
"legality mutation invalid for match");
assert(hasNoSimpleLoops(Rule, Query, Mutation) && "Simple loop detected");
return {Rule.getAction(), Mutation.first, Mutation.second};
} else
LLVM_DEBUG(dbgs() << ".. no match\n");
}
LLVM_DEBUG(dbgs() << ".. unsupported\n");
return {LegalizeAction::Unsupported, 0, LLT{}};
}
bool LegalizeRuleSet::verifyTypeIdxsCoverage(unsigned NumTypeIdxs) const {
#ifndef NDEBUG
if (Rules.empty()) {
LLVM_DEBUG(
dbgs() << ".. type index coverage check SKIPPED: no rules defined\n");
return true;
}
const int64_t FirstUncovered = TypeIdxsCovered.find_first_unset();
if (FirstUncovered < 0) {
LLVM_DEBUG(dbgs() << ".. type index coverage check SKIPPED:"
" user-defined predicate detected\n");
return true;
}
const bool AllCovered = (FirstUncovered >= NumTypeIdxs);
if (NumTypeIdxs > 0)
LLVM_DEBUG(dbgs() << ".. the first uncovered type index: " << FirstUncovered
<< ", " << (AllCovered ? "OK" : "FAIL") << "\n");
return AllCovered;
#else
return true;
#endif
}
bool LegalizeRuleSet::verifyImmIdxsCoverage(unsigned NumImmIdxs) const {
#ifndef NDEBUG
if (Rules.empty()) {
LLVM_DEBUG(
dbgs() << ".. imm index coverage check SKIPPED: no rules defined\n");
return true;
}
const int64_t FirstUncovered = ImmIdxsCovered.find_first_unset();
if (FirstUncovered < 0) {
LLVM_DEBUG(dbgs() << ".. imm index coverage check SKIPPED:"
" user-defined predicate detected\n");
return true;
}
const bool AllCovered = (FirstUncovered >= NumImmIdxs);
LLVM_DEBUG(dbgs() << ".. the first uncovered imm index: " << FirstUncovered
<< ", " << (AllCovered ? "OK" : "FAIL") << "\n");
return AllCovered;
#else
return true;
#endif
}
LegalizerInfo::LegalizerInfo() : TablesInitialized(false) {
// Set defaults.
// FIXME: these two (G_ANYEXT and G_TRUNC?) can be legalized to the
// fundamental load/store Jakob proposed. Once loads & stores are supported.
setScalarAction(TargetOpcode::G_ANYEXT, 1, {{1, Legal}});
setScalarAction(TargetOpcode::G_ZEXT, 1, {{1, Legal}});
setScalarAction(TargetOpcode::G_SEXT, 1, {{1, Legal}});
setScalarAction(TargetOpcode::G_TRUNC, 0, {{1, Legal}});
setScalarAction(TargetOpcode::G_TRUNC, 1, {{1, Legal}});
setScalarAction(TargetOpcode::G_INTRINSIC, 0, {{1, Legal}});
setScalarAction(TargetOpcode::G_INTRINSIC_W_SIDE_EFFECTS, 0, {{1, Legal}});
setLegalizeScalarToDifferentSizeStrategy(
TargetOpcode::G_IMPLICIT_DEF, 0, narrowToSmallerAndUnsupportedIfTooSmall);
setLegalizeScalarToDifferentSizeStrategy(
TargetOpcode::G_ADD, 0, widenToLargerTypesAndNarrowToLargest);
setLegalizeScalarToDifferentSizeStrategy(
TargetOpcode::G_OR, 0, widenToLargerTypesAndNarrowToLargest);
setLegalizeScalarToDifferentSizeStrategy(
TargetOpcode::G_LOAD, 0, narrowToSmallerAndUnsupportedIfTooSmall);
setLegalizeScalarToDifferentSizeStrategy(
TargetOpcode::G_STORE, 0, narrowToSmallerAndUnsupportedIfTooSmall);
setLegalizeScalarToDifferentSizeStrategy(
TargetOpcode::G_BRCOND, 0, widenToLargerTypesUnsupportedOtherwise);
setLegalizeScalarToDifferentSizeStrategy(
TargetOpcode::G_INSERT, 0, narrowToSmallerAndUnsupportedIfTooSmall);
setLegalizeScalarToDifferentSizeStrategy(
TargetOpcode::G_EXTRACT, 0, narrowToSmallerAndUnsupportedIfTooSmall);
setLegalizeScalarToDifferentSizeStrategy(
TargetOpcode::G_EXTRACT, 1, narrowToSmallerAndUnsupportedIfTooSmall);
setScalarAction(TargetOpcode::G_FNEG, 0, {{1, Lower}});
}
void LegalizerInfo::computeTables() {
assert(TablesInitialized == false);
for (unsigned OpcodeIdx = 0; OpcodeIdx <= LastOp - FirstOp; ++OpcodeIdx) {
const unsigned Opcode = FirstOp + OpcodeIdx;
for (unsigned TypeIdx = 0; TypeIdx != SpecifiedActions[OpcodeIdx].size();
++TypeIdx) {
// 0. Collect information specified through the setAction API, i.e.
// for specific bit sizes.
// For scalar types:
SizeAndActionsVec ScalarSpecifiedActions;
// For pointer types:
std::map<uint16_t, SizeAndActionsVec> AddressSpace2SpecifiedActions;
// For vector types:
std::map<uint16_t, SizeAndActionsVec> ElemSize2SpecifiedActions;
for (auto LLT2Action : SpecifiedActions[OpcodeIdx][TypeIdx]) {
const LLT Type = LLT2Action.first;
const LegalizeAction Action = LLT2Action.second;
auto SizeAction = std::make_pair(Type.getSizeInBits(), Action);
if (Type.isPointer())
AddressSpace2SpecifiedActions[Type.getAddressSpace()].push_back(
SizeAction);
else if (Type.isVector())
ElemSize2SpecifiedActions[Type.getElementType().getSizeInBits()]
.push_back(SizeAction);
else
ScalarSpecifiedActions.push_back(SizeAction);
}
// 1. Handle scalar types
{
// Decide how to handle bit sizes for which no explicit specification
// was given.
SizeChangeStrategy S = &unsupportedForDifferentSizes;
if (TypeIdx < ScalarSizeChangeStrategies[OpcodeIdx].size() &&
ScalarSizeChangeStrategies[OpcodeIdx][TypeIdx] != nullptr)
S = ScalarSizeChangeStrategies[OpcodeIdx][TypeIdx];
llvm::sort(ScalarSpecifiedActions);
checkPartialSizeAndActionsVector(ScalarSpecifiedActions);
setScalarAction(Opcode, TypeIdx, S(ScalarSpecifiedActions));
}
// 2. Handle pointer types
for (auto PointerSpecifiedActions : AddressSpace2SpecifiedActions) {
llvm::sort(PointerSpecifiedActions.second);
checkPartialSizeAndActionsVector(PointerSpecifiedActions.second);
// For pointer types, we assume that there isn't a meaningfull way
// to change the number of bits used in the pointer.
setPointerAction(
Opcode, TypeIdx, PointerSpecifiedActions.first,
unsupportedForDifferentSizes(PointerSpecifiedActions.second));
}
// 3. Handle vector types
SizeAndActionsVec ElementSizesSeen;
for (auto VectorSpecifiedActions : ElemSize2SpecifiedActions) {
llvm::sort(VectorSpecifiedActions.second);
const uint16_t ElementSize = VectorSpecifiedActions.first;
ElementSizesSeen.push_back({ElementSize, Legal});
checkPartialSizeAndActionsVector(VectorSpecifiedActions.second);
// For vector types, we assume that the best way to adapt the number
// of elements is to the next larger number of elements type for which
// the vector type is legal, unless there is no such type. In that case,
// legalize towards a vector type with a smaller number of elements.
SizeAndActionsVec NumElementsActions;
for (SizeAndAction BitsizeAndAction : VectorSpecifiedActions.second) {
assert(BitsizeAndAction.first % ElementSize == 0);
const uint16_t NumElements = BitsizeAndAction.first / ElementSize;
NumElementsActions.push_back({NumElements, BitsizeAndAction.second});
}
setVectorNumElementAction(
Opcode, TypeIdx, ElementSize,
moreToWiderTypesAndLessToWidest(NumElementsActions));
}
llvm::sort(ElementSizesSeen);
SizeChangeStrategy VectorElementSizeChangeStrategy =
&unsupportedForDifferentSizes;
if (TypeIdx < VectorElementSizeChangeStrategies[OpcodeIdx].size() &&
VectorElementSizeChangeStrategies[OpcodeIdx][TypeIdx] != nullptr)
VectorElementSizeChangeStrategy =
VectorElementSizeChangeStrategies[OpcodeIdx][TypeIdx];
setScalarInVectorAction(
Opcode, TypeIdx, VectorElementSizeChangeStrategy(ElementSizesSeen));
}
}
TablesInitialized = true;
}
// FIXME: inefficient implementation for now. Without ComputeValueVTs we're
// probably going to need specialized lookup structures for various types before
// we have any hope of doing well with something like <13 x i3>. Even the common
// cases should do better than what we have now.
std::pair<LegalizeAction, LLT>
LegalizerInfo::getAspectAction(const InstrAspect &Aspect) const {
assert(TablesInitialized && "backend forgot to call computeTables");
// These *have* to be implemented for now, they're the fundamental basis of
// how everything else is transformed.
if (Aspect.Type.isScalar() || Aspect.Type.isPointer())
return findScalarLegalAction(Aspect);
assert(Aspect.Type.isVector());
return findVectorLegalAction(Aspect);
}
/// Helper function to get LLT for the given type index.
static LLT getTypeFromTypeIdx(const MachineInstr &MI,
const MachineRegisterInfo &MRI, unsigned OpIdx,
unsigned TypeIdx) {
assert(TypeIdx < MI.getNumOperands() && "Unexpected TypeIdx");
// G_UNMERGE_VALUES has variable number of operands, but there is only
// one source type and one destination type as all destinations must be the
// same type. So, get the last operand if TypeIdx == 1.
if (MI.getOpcode() == TargetOpcode::G_UNMERGE_VALUES && TypeIdx == 1)
return MRI.getType(MI.getOperand(MI.getNumOperands() - 1).getReg());
return MRI.getType(MI.getOperand(OpIdx).getReg());
}
unsigned LegalizerInfo::getOpcodeIdxForOpcode(unsigned Opcode) const {
assert(Opcode >= FirstOp && Opcode <= LastOp && "Unsupported opcode");
return Opcode - FirstOp;
}
unsigned LegalizerInfo::getActionDefinitionsIdx(unsigned Opcode) const {
unsigned OpcodeIdx = getOpcodeIdxForOpcode(Opcode);
if (unsigned Alias = RulesForOpcode[OpcodeIdx].getAlias()) {
LLVM_DEBUG(dbgs() << ".. opcode " << Opcode << " is aliased to " << Alias
<< "\n");
OpcodeIdx = getOpcodeIdxForOpcode(Alias);
assert(RulesForOpcode[OpcodeIdx].getAlias() == 0 && "Cannot chain aliases");
}
return OpcodeIdx;
}
const LegalizeRuleSet &
LegalizerInfo::getActionDefinitions(unsigned Opcode) const {
unsigned OpcodeIdx = getActionDefinitionsIdx(Opcode);
return RulesForOpcode[OpcodeIdx];
}
LegalizeRuleSet &LegalizerInfo::getActionDefinitionsBuilder(unsigned Opcode) {
unsigned OpcodeIdx = getActionDefinitionsIdx(Opcode);
auto &Result = RulesForOpcode[OpcodeIdx];
assert(!Result.isAliasedByAnother() && "Modifying this opcode will modify aliases");
return Result;
}
LegalizeRuleSet &LegalizerInfo::getActionDefinitionsBuilder(
std::initializer_list<unsigned> Opcodes) {
unsigned Representative = *Opcodes.begin();
assert(!llvm::empty(Opcodes) && Opcodes.begin() + 1 != Opcodes.end() &&
"Initializer list must have at least two opcodes");
for (auto I = Opcodes.begin() + 1, E = Opcodes.end(); I != E; ++I)
aliasActionDefinitions(Representative, *I);
auto &Return = getActionDefinitionsBuilder(Representative);
Return.setIsAliasedByAnother();
return Return;
}
void LegalizerInfo::aliasActionDefinitions(unsigned OpcodeTo,
unsigned OpcodeFrom) {
assert(OpcodeTo != OpcodeFrom && "Cannot alias to self");
assert(OpcodeTo >= FirstOp && OpcodeTo <= LastOp && "Unsupported opcode");
const unsigned OpcodeFromIdx = getOpcodeIdxForOpcode(OpcodeFrom);
RulesForOpcode[OpcodeFromIdx].aliasTo(OpcodeTo);
}
LegalizeActionStep
LegalizerInfo::getAction(const LegalityQuery &Query) const {
LegalizeActionStep Step = getActionDefinitions(Query.Opcode).apply(Query);
if (Step.Action != LegalizeAction::UseLegacyRules) {
return Step;
}
for (unsigned i = 0; i < Query.Types.size(); ++i) {
auto Action = getAspectAction({Query.Opcode, i, Query.Types[i]});
if (Action.first != Legal) {
LLVM_DEBUG(dbgs() << ".. (legacy) Type " << i << " Action="
<< Action.first << ", " << Action.second << "\n");
return {Action.first, i, Action.second};
} else
LLVM_DEBUG(dbgs() << ".. (legacy) Type " << i << " Legal\n");
}
LLVM_DEBUG(dbgs() << ".. (legacy) Legal\n");
return {Legal, 0, LLT{}};
}
LegalizeActionStep
LegalizerInfo::getAction(const MachineInstr &MI,
const MachineRegisterInfo &MRI) const {
SmallVector<LLT, 2> Types;
SmallBitVector SeenTypes(8);
const MCOperandInfo *OpInfo = MI.getDesc().OpInfo;
// FIXME: probably we'll need to cache the results here somehow?
for (unsigned i = 0; i < MI.getDesc().getNumOperands(); ++i) {
if (!OpInfo[i].isGenericType())
continue;
// We must only record actions once for each TypeIdx; otherwise we'd
// try to legalize operands multiple times down the line.
unsigned TypeIdx = OpInfo[i].getGenericTypeIndex();
if (SeenTypes[TypeIdx])
continue;
SeenTypes.set(TypeIdx);
LLT Ty = getTypeFromTypeIdx(MI, MRI, i, TypeIdx);
Types.push_back(Ty);
}
SmallVector<LegalityQuery::MemDesc, 2> MemDescrs;
for (const auto &MMO : MI.memoperands())
MemDescrs.push_back({8 * MMO->getSize() /* in bits */,
8 * MMO->getAlignment(),
MMO->getOrdering()});
return getAction({MI.getOpcode(), Types, MemDescrs});
}
bool LegalizerInfo::isLegal(const MachineInstr &MI,
const MachineRegisterInfo &MRI) const {
return getAction(MI, MRI).Action == Legal;
}
bool LegalizerInfo::isLegalOrCustom(const MachineInstr &MI,
const MachineRegisterInfo &MRI) const {
auto Action = getAction(MI, MRI).Action;
// If the action is custom, it may not necessarily modify the instruction,
// so we have to assume it's legal.
return Action == Legal || Action == Custom;
}
bool LegalizerInfo::legalizeCustom(MachineInstr &MI, MachineRegisterInfo &MRI,
MachineIRBuilder &MIRBuilder,
GISelChangeObserver &Observer) const {
return false;
}
LegalizerInfo::SizeAndActionsVec
LegalizerInfo::increaseToLargerTypesAndDecreaseToLargest(
const SizeAndActionsVec &v, LegalizeAction IncreaseAction,
LegalizeAction DecreaseAction) {
SizeAndActionsVec result;
unsigned LargestSizeSoFar = 0;
if (v.size() >= 1 && v[0].first != 1)
result.push_back({1, IncreaseAction});
for (size_t i = 0; i < v.size(); ++i) {
result.push_back(v[i]);
LargestSizeSoFar = v[i].first;
if (i + 1 < v.size() && v[i + 1].first != v[i].first + 1) {
result.push_back({LargestSizeSoFar + 1, IncreaseAction});
LargestSizeSoFar = v[i].first + 1;
}
}
result.push_back({LargestSizeSoFar + 1, DecreaseAction});
return result;
}
LegalizerInfo::SizeAndActionsVec
LegalizerInfo::decreaseToSmallerTypesAndIncreaseToSmallest(
const SizeAndActionsVec &v, LegalizeAction DecreaseAction,
LegalizeAction IncreaseAction) {
SizeAndActionsVec result;
if (v.size() == 0 || v[0].first != 1)
result.push_back({1, IncreaseAction});
for (size_t i = 0; i < v.size(); ++i) {
result.push_back(v[i]);
if (i + 1 == v.size() || v[i + 1].first != v[i].first + 1) {
result.push_back({v[i].first + 1, DecreaseAction});
}
}
return result;
}
LegalizerInfo::SizeAndAction
LegalizerInfo::findAction(const SizeAndActionsVec &Vec, const uint32_t Size) {
assert(Size >= 1);
// Find the last element in Vec that has a bitsize equal to or smaller than
// the requested bit size.
// That is the element just before the first element that is bigger than Size.
auto It = partition_point(
Vec, [=](const SizeAndAction &A) { return A.first <= Size; });
assert(It != Vec.begin() && "Does Vec not start with size 1?");
int VecIdx = It - Vec.begin() - 1;
LegalizeAction Action = Vec[VecIdx].second;
switch (Action) {
case Legal:
case Lower:
case Libcall:
case Custom:
return {Size, Action};
case FewerElements:
// FIXME: is this special case still needed and correct?
// Special case for scalarization:
if (Vec == SizeAndActionsVec({{1, FewerElements}}))
return {1, FewerElements};
LLVM_FALLTHROUGH;
case NarrowScalar: {
// The following needs to be a loop, as for now, we do allow needing to
// go over "Unsupported" bit sizes before finding a legalizable bit size.
// e.g. (s8, WidenScalar), (s9, Unsupported), (s32, Legal). if Size==8,
// we need to iterate over s9, and then to s32 to return (s32, Legal).
// If we want to get rid of the below loop, we should have stronger asserts
// when building the SizeAndActionsVecs, probably not allowing
// "Unsupported" unless at the ends of the vector.
for (int i = VecIdx - 1; i >= 0; --i)
if (!needsLegalizingToDifferentSize(Vec[i].second) &&
Vec[i].second != Unsupported)
return {Vec[i].first, Action};
llvm_unreachable("");
}
case WidenScalar:
case MoreElements: {
// See above, the following needs to be a loop, at least for now.
for (std::size_t i = VecIdx + 1; i < Vec.size(); ++i)
if (!needsLegalizingToDifferentSize(Vec[i].second) &&
Vec[i].second != Unsupported)
return {Vec[i].first, Action};
llvm_unreachable("");
}
case Unsupported:
return {Size, Unsupported};
case NotFound:
case UseLegacyRules:
llvm_unreachable("NotFound");
}
llvm_unreachable("Action has an unknown enum value");
}
std::pair<LegalizeAction, LLT>
LegalizerInfo::findScalarLegalAction(const InstrAspect &Aspect) const {
assert(Aspect.Type.isScalar() || Aspect.Type.isPointer());
if (Aspect.Opcode < FirstOp || Aspect.Opcode > LastOp)
return {NotFound, LLT()};
const unsigned OpcodeIdx = getOpcodeIdxForOpcode(Aspect.Opcode);
if (Aspect.Type.isPointer() &&
AddrSpace2PointerActions[OpcodeIdx].find(Aspect.Type.getAddressSpace()) ==
AddrSpace2PointerActions[OpcodeIdx].end()) {
return {NotFound, LLT()};
}
const SmallVector<SizeAndActionsVec, 1> &Actions =
Aspect.Type.isPointer()
? AddrSpace2PointerActions[OpcodeIdx]
.find(Aspect.Type.getAddressSpace())
->second
: ScalarActions[OpcodeIdx];
if (Aspect.Idx >= Actions.size())
return {NotFound, LLT()};
const SizeAndActionsVec &Vec = Actions[Aspect.Idx];
// FIXME: speed up this search, e.g. by using a results cache for repeated
// queries?
auto SizeAndAction = findAction(Vec, Aspect.Type.getSizeInBits());
return {SizeAndAction.second,
Aspect.Type.isScalar() ? LLT::scalar(SizeAndAction.first)
: LLT::pointer(Aspect.Type.getAddressSpace(),
SizeAndAction.first)};
}
std::pair<LegalizeAction, LLT>
LegalizerInfo::findVectorLegalAction(const InstrAspect &Aspect) const {
assert(Aspect.Type.isVector());
// First legalize the vector element size, then legalize the number of
// lanes in the vector.
if (Aspect.Opcode < FirstOp || Aspect.Opcode > LastOp)
return {NotFound, Aspect.Type};
const unsigned OpcodeIdx = getOpcodeIdxForOpcode(Aspect.Opcode);
const unsigned TypeIdx = Aspect.Idx;
if (TypeIdx >= ScalarInVectorActions[OpcodeIdx].size())
return {NotFound, Aspect.Type};
const SizeAndActionsVec &ElemSizeVec =
ScalarInVectorActions[OpcodeIdx][TypeIdx];
LLT IntermediateType;
auto ElementSizeAndAction =
findAction(ElemSizeVec, Aspect.Type.getScalarSizeInBits());
IntermediateType =
LLT::vector(Aspect.Type.getNumElements(), ElementSizeAndAction.first);
if (ElementSizeAndAction.second != Legal)
return {ElementSizeAndAction.second, IntermediateType};
auto i = NumElements2Actions[OpcodeIdx].find(
IntermediateType.getScalarSizeInBits());
if (i == NumElements2Actions[OpcodeIdx].end()) {
return {NotFound, IntermediateType};
}
const SizeAndActionsVec &NumElementsVec = (*i).second[TypeIdx];
auto NumElementsAndAction =
findAction(NumElementsVec, IntermediateType.getNumElements());
return {NumElementsAndAction.second,
LLT::vector(NumElementsAndAction.first,
IntermediateType.getScalarSizeInBits())};
}
bool LegalizerInfo::legalizeIntrinsic(MachineInstr &MI,
MachineIRBuilder &MIRBuilder,
GISelChangeObserver &Observer) const {
return true;
}
unsigned LegalizerInfo::getExtOpcodeForWideningConstant(LLT SmallTy) const {
return SmallTy.isByteSized() ? TargetOpcode::G_SEXT : TargetOpcode::G_ZEXT;
}
/// \pre Type indices of every opcode form a dense set starting from 0.
void LegalizerInfo::verify(const MCInstrInfo &MII) const {
#ifndef NDEBUG
std::vector<unsigned> FailedOpcodes;
for (unsigned Opcode = FirstOp; Opcode <= LastOp; ++Opcode) {
const MCInstrDesc &MCID = MII.get(Opcode);
const unsigned NumTypeIdxs = std::accumulate(
MCID.opInfo_begin(), MCID.opInfo_end(), 0U,
[](unsigned Acc, const MCOperandInfo &OpInfo) {
return OpInfo.isGenericType()
? std::max(OpInfo.getGenericTypeIndex() + 1U, Acc)
: Acc;
});
const unsigned NumImmIdxs = std::accumulate(
MCID.opInfo_begin(), MCID.opInfo_end(), 0U,
[](unsigned Acc, const MCOperandInfo &OpInfo) {
return OpInfo.isGenericImm()
? std::max(OpInfo.getGenericImmIndex() + 1U, Acc)
: Acc;
});
LLVM_DEBUG(dbgs() << MII.getName(Opcode) << " (opcode " << Opcode
<< "): " << NumTypeIdxs << " type ind"
<< (NumTypeIdxs == 1 ? "ex" : "ices") << ", "
<< NumImmIdxs << " imm ind"
<< (NumImmIdxs == 1 ? "ex" : "ices") << "\n");
const LegalizeRuleSet &RuleSet = getActionDefinitions(Opcode);
if (!RuleSet.verifyTypeIdxsCoverage(NumTypeIdxs))
FailedOpcodes.push_back(Opcode);
else if (!RuleSet.verifyImmIdxsCoverage(NumImmIdxs))
FailedOpcodes.push_back(Opcode);
}
if (!FailedOpcodes.empty()) {
errs() << "The following opcodes have ill-defined legalization rules:";
for (unsigned Opcode : FailedOpcodes)
errs() << " " << MII.getName(Opcode);
errs() << "\n";
report_fatal_error("ill-defined LegalizerInfo"
", try -debug-only=legalizer-info for details");
}
#endif
}
#ifndef NDEBUG
// FIXME: This should be in the MachineVerifier, but it can't use the
// LegalizerInfo as it's currently in the separate GlobalISel library.
// Note that RegBankSelected property already checked in the verifier
// has the same layering problem, but we only use inline methods so
// end up not needing to link against the GlobalISel library.
const MachineInstr *llvm::machineFunctionIsIllegal(const MachineFunction &MF) {
if (const LegalizerInfo *MLI = MF.getSubtarget().getLegalizerInfo()) {
const MachineRegisterInfo &MRI = MF.getRegInfo();
for (const MachineBasicBlock &MBB : MF)
for (const MachineInstr &MI : MBB)
if (isPreISelGenericOpcode(MI.getOpcode()) &&
!MLI->isLegalOrCustom(MI, MRI))
return &MI;
}
return nullptr;
}
#endif
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