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llvm-mirror/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
Matt Arsenault 4211eac508 GlobalISel: Make default implementation of legalizeCustom unreachable 
If the target explicitly requested custom legalization, it should be
required to implement this. Also move default legalizeIntrinsic
implementation into the header so it's next to the related
legalizeCustom.
2020-06-10 11:05:59 -04:00

749 lines
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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 Bitcast:
OS << "Bitcast";
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;
}
case Bitcast: {
return OldTy != NewTy && OldTy.getSizeInBits() == NewTy.getSizeInBits();
}
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->getAlign().value(), 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;
}
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 Bitcast:
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())};
}
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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