llvm-project/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp
Diana Picus 1027249ec9 [ARM GlobalISel] Nothing is legal for Thumb
...yet!

A lot of the current code should be shared for arm and thumb mode, but
until we add tests and work out some of the details (e.g. checking the
correct subtarget feature for G_SDIV) it's safer to bail out as early as
possible for thumb targets.

This should have arguably been part of r348347, which allowed Thumb
functions to be handled by the IR Translator.

llvm-svn: 348472
2018-12-06 09:26:14 +00:00

447 lines
18 KiB
C++

//===- ARMLegalizerInfo.cpp --------------------------------------*- C++ -*-==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
/// \file
/// This file implements the targeting of the Machinelegalizer class for ARM.
/// \todo This should be generated by TableGen.
//===----------------------------------------------------------------------===//
#include "ARMLegalizerInfo.h"
#include "ARMCallLowering.h"
#include "ARMSubtarget.h"
#include "llvm/CodeGen/GlobalISel/LegalizerHelper.h"
#include "llvm/CodeGen/LowLevelType.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetOpcodes.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Type.h"
using namespace llvm;
using namespace LegalizeActions;
/// FIXME: The following static functions are SizeChangeStrategy functions
/// that are meant to temporarily mimic the behaviour of the old legalization
/// based on doubling/halving non-legal types as closely as possible. This is
/// not entirly possible as only legalizing the types that are exactly a power
/// of 2 times the size of the legal types would require specifying all those
/// sizes explicitly.
/// In practice, not specifying those isn't a problem, and the below functions
/// should disappear quickly as we add support for legalizing non-power-of-2
/// sized types further.
static void
addAndInterleaveWithUnsupported(LegalizerInfo::SizeAndActionsVec &result,
const LegalizerInfo::SizeAndActionsVec &v) {
for (unsigned i = 0; i < v.size(); ++i) {
result.push_back(v[i]);
if (i + 1 < v[i].first && i + 1 < v.size() &&
v[i + 1].first != v[i].first + 1)
result.push_back({v[i].first + 1, Unsupported});
}
}
static LegalizerInfo::SizeAndActionsVec
widen_8_16(const LegalizerInfo::SizeAndActionsVec &v) {
assert(v.size() >= 1);
assert(v[0].first > 17);
LegalizerInfo::SizeAndActionsVec result = {{1, Unsupported},
{8, WidenScalar},
{9, Unsupported},
{16, WidenScalar},
{17, Unsupported}};
addAndInterleaveWithUnsupported(result, v);
auto Largest = result.back().first;
result.push_back({Largest + 1, Unsupported});
return result;
}
static bool AEABI(const ARMSubtarget &ST) {
return ST.isTargetAEABI() || ST.isTargetGNUAEABI() || ST.isTargetMuslAEABI();
}
ARMLegalizerInfo::ARMLegalizerInfo(const ARMSubtarget &ST) {
using namespace TargetOpcode;
const LLT p0 = LLT::pointer(0, 32);
const LLT s1 = LLT::scalar(1);
const LLT s8 = LLT::scalar(8);
const LLT s16 = LLT::scalar(16);
const LLT s32 = LLT::scalar(32);
const LLT s64 = LLT::scalar(64);
if (ST.isThumb()) {
// FIXME: merge with the code for non-Thumb.
computeTables();
verify(*ST.getInstrInfo());
return;
}
getActionDefinitionsBuilder(G_GLOBAL_VALUE).legalFor({p0});
getActionDefinitionsBuilder(G_FRAME_INDEX).legalFor({p0});
getActionDefinitionsBuilder({G_ADD, G_SUB, G_MUL, G_AND, G_OR, G_XOR})
.legalFor({s32})
.minScalar(0, s32);
if (ST.hasDivideInARMMode())
getActionDefinitionsBuilder({G_SDIV, G_UDIV})
.legalFor({s32})
.clampScalar(0, s32, s32);
else
getActionDefinitionsBuilder({G_SDIV, G_UDIV})
.libcallFor({s32})
.clampScalar(0, s32, s32);
for (unsigned Op : {G_SREM, G_UREM}) {
setLegalizeScalarToDifferentSizeStrategy(Op, 0, widen_8_16);
if (ST.hasDivideInARMMode())
setAction({Op, s32}, Lower);
else if (AEABI(ST))
setAction({Op, s32}, Custom);
else
setAction({Op, s32}, Libcall);
}
getActionDefinitionsBuilder({G_SEXT, G_ZEXT, G_ANYEXT})
.legalForCartesianProduct({s32}, {s1, s8, s16});
getActionDefinitionsBuilder(G_INTTOPTR).legalFor({{p0, s32}});
getActionDefinitionsBuilder(G_PTRTOINT).legalFor({{s32, p0}});
getActionDefinitionsBuilder({G_ASHR, G_LSHR, G_SHL}).legalFor({s32});
if (ST.hasV5TOps()) {
getActionDefinitionsBuilder(G_CTLZ)
.legalFor({s32})
.clampScalar(0, s32, s32);
getActionDefinitionsBuilder(G_CTLZ_ZERO_UNDEF)
.lowerFor({s32})
.clampScalar(0, s32, s32);
} else {
getActionDefinitionsBuilder(G_CTLZ_ZERO_UNDEF)
.libcallFor({s32})
.clampScalar(0, s32, s32);
getActionDefinitionsBuilder(G_CTLZ)
.lowerFor({s32})
.clampScalar(0, s32, s32);
}
getActionDefinitionsBuilder(G_GEP).legalFor({{p0, s32}});
getActionDefinitionsBuilder(G_SELECT).legalForCartesianProduct({s32, p0},
{s1});
getActionDefinitionsBuilder(G_BRCOND).legalFor({s1});
getActionDefinitionsBuilder(G_CONSTANT)
.legalFor({s32, p0})
.clampScalar(0, s32, s32);
getActionDefinitionsBuilder(G_ICMP)
.legalForCartesianProduct({s1}, {s32, p0})
.minScalar(1, s32);
// We're keeping these builders around because we'll want to add support for
// floating point to them.
auto &LoadStoreBuilder =
getActionDefinitionsBuilder({G_LOAD, G_STORE})
.legalForCartesianProduct({s1, s8, s16, s32, p0}, {p0});
auto &PhiBuilder =
getActionDefinitionsBuilder(G_PHI).legalFor({s32, p0}).minScalar(0, s32);
if (!ST.useSoftFloat() && ST.hasVFP2()) {
getActionDefinitionsBuilder(
{G_FADD, G_FSUB, G_FMUL, G_FDIV, G_FCONSTANT, G_FNEG})
.legalFor({s32, s64});
LoadStoreBuilder.legalFor({{s64, p0}});
PhiBuilder.legalFor({s64});
getActionDefinitionsBuilder(G_FCMP).legalForCartesianProduct({s1},
{s32, s64});
getActionDefinitionsBuilder(G_MERGE_VALUES).legalFor({{s64, s32}});
getActionDefinitionsBuilder(G_UNMERGE_VALUES).legalFor({{s32, s64}});
getActionDefinitionsBuilder(G_FPEXT).legalFor({{s64, s32}});
getActionDefinitionsBuilder(G_FPTRUNC).legalFor({{s32, s64}});
getActionDefinitionsBuilder({G_FPTOSI, G_FPTOUI})
.legalForCartesianProduct({s32}, {s32, s64});
getActionDefinitionsBuilder({G_SITOFP, G_UITOFP})
.legalForCartesianProduct({s32, s64}, {s32});
} else {
getActionDefinitionsBuilder({G_FADD, G_FSUB, G_FMUL, G_FDIV})
.libcallFor({s32, s64});
LoadStoreBuilder.maxScalar(0, s32);
for (auto Ty : {s32, s64})
setAction({G_FNEG, Ty}, Lower);
getActionDefinitionsBuilder(G_FCONSTANT).customFor({s32, s64});
getActionDefinitionsBuilder(G_FCMP).customForCartesianProduct({s1},
{s32, s64});
if (AEABI(ST))
setFCmpLibcallsAEABI();
else
setFCmpLibcallsGNU();
getActionDefinitionsBuilder(G_FPEXT).libcallFor({{s64, s32}});
getActionDefinitionsBuilder(G_FPTRUNC).libcallFor({{s32, s64}});
getActionDefinitionsBuilder({G_FPTOSI, G_FPTOUI})
.libcallForCartesianProduct({s32}, {s32, s64});
getActionDefinitionsBuilder({G_SITOFP, G_UITOFP})
.libcallForCartesianProduct({s32, s64}, {s32});
}
if (!ST.useSoftFloat() && ST.hasVFP4())
getActionDefinitionsBuilder(G_FMA).legalFor({s32, s64});
else
getActionDefinitionsBuilder(G_FMA).libcallFor({s32, s64});
getActionDefinitionsBuilder({G_FREM, G_FPOW}).libcallFor({s32, s64});
computeTables();
verify(*ST.getInstrInfo());
}
void ARMLegalizerInfo::setFCmpLibcallsAEABI() {
// FCMP_TRUE and FCMP_FALSE don't need libcalls, they should be
// default-initialized.
FCmp32Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
FCmp32Libcalls[CmpInst::FCMP_OEQ] = {
{RTLIB::OEQ_F32, CmpInst::BAD_ICMP_PREDICATE}};
FCmp32Libcalls[CmpInst::FCMP_OGE] = {
{RTLIB::OGE_F32, CmpInst::BAD_ICMP_PREDICATE}};
FCmp32Libcalls[CmpInst::FCMP_OGT] = {
{RTLIB::OGT_F32, CmpInst::BAD_ICMP_PREDICATE}};
FCmp32Libcalls[CmpInst::FCMP_OLE] = {
{RTLIB::OLE_F32, CmpInst::BAD_ICMP_PREDICATE}};
FCmp32Libcalls[CmpInst::FCMP_OLT] = {
{RTLIB::OLT_F32, CmpInst::BAD_ICMP_PREDICATE}};
FCmp32Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::O_F32, CmpInst::ICMP_EQ}};
FCmp32Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F32, CmpInst::ICMP_EQ}};
FCmp32Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F32, CmpInst::ICMP_EQ}};
FCmp32Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F32, CmpInst::ICMP_EQ}};
FCmp32Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F32, CmpInst::ICMP_EQ}};
FCmp32Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F32, CmpInst::ICMP_EQ}};
FCmp32Libcalls[CmpInst::FCMP_UNO] = {
{RTLIB::UO_F32, CmpInst::BAD_ICMP_PREDICATE}};
FCmp32Libcalls[CmpInst::FCMP_ONE] = {
{RTLIB::OGT_F32, CmpInst::BAD_ICMP_PREDICATE},
{RTLIB::OLT_F32, CmpInst::BAD_ICMP_PREDICATE}};
FCmp32Libcalls[CmpInst::FCMP_UEQ] = {
{RTLIB::OEQ_F32, CmpInst::BAD_ICMP_PREDICATE},
{RTLIB::UO_F32, CmpInst::BAD_ICMP_PREDICATE}};
FCmp64Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
FCmp64Libcalls[CmpInst::FCMP_OEQ] = {
{RTLIB::OEQ_F64, CmpInst::BAD_ICMP_PREDICATE}};
FCmp64Libcalls[CmpInst::FCMP_OGE] = {
{RTLIB::OGE_F64, CmpInst::BAD_ICMP_PREDICATE}};
FCmp64Libcalls[CmpInst::FCMP_OGT] = {
{RTLIB::OGT_F64, CmpInst::BAD_ICMP_PREDICATE}};
FCmp64Libcalls[CmpInst::FCMP_OLE] = {
{RTLIB::OLE_F64, CmpInst::BAD_ICMP_PREDICATE}};
FCmp64Libcalls[CmpInst::FCMP_OLT] = {
{RTLIB::OLT_F64, CmpInst::BAD_ICMP_PREDICATE}};
FCmp64Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::O_F64, CmpInst::ICMP_EQ}};
FCmp64Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F64, CmpInst::ICMP_EQ}};
FCmp64Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F64, CmpInst::ICMP_EQ}};
FCmp64Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F64, CmpInst::ICMP_EQ}};
FCmp64Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F64, CmpInst::ICMP_EQ}};
FCmp64Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F64, CmpInst::ICMP_EQ}};
FCmp64Libcalls[CmpInst::FCMP_UNO] = {
{RTLIB::UO_F64, CmpInst::BAD_ICMP_PREDICATE}};
FCmp64Libcalls[CmpInst::FCMP_ONE] = {
{RTLIB::OGT_F64, CmpInst::BAD_ICMP_PREDICATE},
{RTLIB::OLT_F64, CmpInst::BAD_ICMP_PREDICATE}};
FCmp64Libcalls[CmpInst::FCMP_UEQ] = {
{RTLIB::OEQ_F64, CmpInst::BAD_ICMP_PREDICATE},
{RTLIB::UO_F64, CmpInst::BAD_ICMP_PREDICATE}};
}
void ARMLegalizerInfo::setFCmpLibcallsGNU() {
// FCMP_TRUE and FCMP_FALSE don't need libcalls, they should be
// default-initialized.
FCmp32Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
FCmp32Libcalls[CmpInst::FCMP_OEQ] = {{RTLIB::OEQ_F32, CmpInst::ICMP_EQ}};
FCmp32Libcalls[CmpInst::FCMP_OGE] = {{RTLIB::OGE_F32, CmpInst::ICMP_SGE}};
FCmp32Libcalls[CmpInst::FCMP_OGT] = {{RTLIB::OGT_F32, CmpInst::ICMP_SGT}};
FCmp32Libcalls[CmpInst::FCMP_OLE] = {{RTLIB::OLE_F32, CmpInst::ICMP_SLE}};
FCmp32Libcalls[CmpInst::FCMP_OLT] = {{RTLIB::OLT_F32, CmpInst::ICMP_SLT}};
FCmp32Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::O_F32, CmpInst::ICMP_EQ}};
FCmp32Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F32, CmpInst::ICMP_SGE}};
FCmp32Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F32, CmpInst::ICMP_SGT}};
FCmp32Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F32, CmpInst::ICMP_SLE}};
FCmp32Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F32, CmpInst::ICMP_SLT}};
FCmp32Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F32, CmpInst::ICMP_NE}};
FCmp32Libcalls[CmpInst::FCMP_UNO] = {{RTLIB::UO_F32, CmpInst::ICMP_NE}};
FCmp32Libcalls[CmpInst::FCMP_ONE] = {{RTLIB::OGT_F32, CmpInst::ICMP_SGT},
{RTLIB::OLT_F32, CmpInst::ICMP_SLT}};
FCmp32Libcalls[CmpInst::FCMP_UEQ] = {{RTLIB::OEQ_F32, CmpInst::ICMP_EQ},
{RTLIB::UO_F32, CmpInst::ICMP_NE}};
FCmp64Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
FCmp64Libcalls[CmpInst::FCMP_OEQ] = {{RTLIB::OEQ_F64, CmpInst::ICMP_EQ}};
FCmp64Libcalls[CmpInst::FCMP_OGE] = {{RTLIB::OGE_F64, CmpInst::ICMP_SGE}};
FCmp64Libcalls[CmpInst::FCMP_OGT] = {{RTLIB::OGT_F64, CmpInst::ICMP_SGT}};
FCmp64Libcalls[CmpInst::FCMP_OLE] = {{RTLIB::OLE_F64, CmpInst::ICMP_SLE}};
FCmp64Libcalls[CmpInst::FCMP_OLT] = {{RTLIB::OLT_F64, CmpInst::ICMP_SLT}};
FCmp64Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::O_F64, CmpInst::ICMP_EQ}};
FCmp64Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F64, CmpInst::ICMP_SGE}};
FCmp64Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F64, CmpInst::ICMP_SGT}};
FCmp64Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F64, CmpInst::ICMP_SLE}};
FCmp64Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F64, CmpInst::ICMP_SLT}};
FCmp64Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F64, CmpInst::ICMP_NE}};
FCmp64Libcalls[CmpInst::FCMP_UNO] = {{RTLIB::UO_F64, CmpInst::ICMP_NE}};
FCmp64Libcalls[CmpInst::FCMP_ONE] = {{RTLIB::OGT_F64, CmpInst::ICMP_SGT},
{RTLIB::OLT_F64, CmpInst::ICMP_SLT}};
FCmp64Libcalls[CmpInst::FCMP_UEQ] = {{RTLIB::OEQ_F64, CmpInst::ICMP_EQ},
{RTLIB::UO_F64, CmpInst::ICMP_NE}};
}
ARMLegalizerInfo::FCmpLibcallsList
ARMLegalizerInfo::getFCmpLibcalls(CmpInst::Predicate Predicate,
unsigned Size) const {
assert(CmpInst::isFPPredicate(Predicate) && "Unsupported FCmp predicate");
if (Size == 32)
return FCmp32Libcalls[Predicate];
if (Size == 64)
return FCmp64Libcalls[Predicate];
llvm_unreachable("Unsupported size for FCmp predicate");
}
bool ARMLegalizerInfo::legalizeCustom(MachineInstr &MI,
MachineRegisterInfo &MRI,
MachineIRBuilder &MIRBuilder,
GISelChangeObserver &Observer) const {
using namespace TargetOpcode;
MIRBuilder.setInstr(MI);
LLVMContext &Ctx = MIRBuilder.getMF().getFunction().getContext();
switch (MI.getOpcode()) {
default:
return false;
case G_SREM:
case G_UREM: {
unsigned OriginalResult = MI.getOperand(0).getReg();
auto Size = MRI.getType(OriginalResult).getSizeInBits();
if (Size != 32)
return false;
auto Libcall =
MI.getOpcode() == G_SREM ? RTLIB::SDIVREM_I32 : RTLIB::UDIVREM_I32;
// Our divmod libcalls return a struct containing the quotient and the
// remainder. We need to create a virtual register for it.
Type *ArgTy = Type::getInt32Ty(Ctx);
StructType *RetTy = StructType::get(Ctx, {ArgTy, ArgTy}, /* Packed */ true);
auto RetVal = MRI.createGenericVirtualRegister(
getLLTForType(*RetTy, MIRBuilder.getMF().getDataLayout()));
auto Status = createLibcall(MIRBuilder, Libcall, {RetVal, RetTy},
{{MI.getOperand(1).getReg(), ArgTy},
{MI.getOperand(2).getReg(), ArgTy}});
if (Status != LegalizerHelper::Legalized)
return false;
// The remainder is the second result of divmod. Split the return value into
// a new, unused register for the quotient and the destination of the
// original instruction for the remainder.
MIRBuilder.buildUnmerge(
{MRI.createGenericVirtualRegister(LLT::scalar(32)), OriginalResult},
RetVal);
break;
}
case G_FCMP: {
assert(MRI.getType(MI.getOperand(2).getReg()) ==
MRI.getType(MI.getOperand(3).getReg()) &&
"Mismatched operands for G_FCMP");
auto OpSize = MRI.getType(MI.getOperand(2).getReg()).getSizeInBits();
auto OriginalResult = MI.getOperand(0).getReg();
auto Predicate =
static_cast<CmpInst::Predicate>(MI.getOperand(1).getPredicate());
auto Libcalls = getFCmpLibcalls(Predicate, OpSize);
if (Libcalls.empty()) {
assert((Predicate == CmpInst::FCMP_TRUE ||
Predicate == CmpInst::FCMP_FALSE) &&
"Predicate needs libcalls, but none specified");
MIRBuilder.buildConstant(OriginalResult,
Predicate == CmpInst::FCMP_TRUE ? 1 : 0);
MI.eraseFromParent();
return true;
}
assert((OpSize == 32 || OpSize == 64) && "Unsupported operand size");
auto *ArgTy = OpSize == 32 ? Type::getFloatTy(Ctx) : Type::getDoubleTy(Ctx);
auto *RetTy = Type::getInt32Ty(Ctx);
SmallVector<unsigned, 2> Results;
for (auto Libcall : Libcalls) {
auto LibcallResult = MRI.createGenericVirtualRegister(LLT::scalar(32));
auto Status =
createLibcall(MIRBuilder, Libcall.LibcallID, {LibcallResult, RetTy},
{{MI.getOperand(2).getReg(), ArgTy},
{MI.getOperand(3).getReg(), ArgTy}});
if (Status != LegalizerHelper::Legalized)
return false;
auto ProcessedResult =
Libcalls.size() == 1
? OriginalResult
: MRI.createGenericVirtualRegister(MRI.getType(OriginalResult));
// We have a result, but we need to transform it into a proper 1-bit 0 or
// 1, taking into account the different peculiarities of the values
// returned by the comparison functions.
CmpInst::Predicate ResultPred = Libcall.Predicate;
if (ResultPred == CmpInst::BAD_ICMP_PREDICATE) {
// We have a nice 0 or 1, and we just need to truncate it back to 1 bit
// to keep the types consistent.
MIRBuilder.buildTrunc(ProcessedResult, LibcallResult);
} else {
// We need to compare against 0.
assert(CmpInst::isIntPredicate(ResultPred) && "Unsupported predicate");
auto Zero = MRI.createGenericVirtualRegister(LLT::scalar(32));
MIRBuilder.buildConstant(Zero, 0);
MIRBuilder.buildICmp(ResultPred, ProcessedResult, LibcallResult, Zero);
}
Results.push_back(ProcessedResult);
}
if (Results.size() != 1) {
assert(Results.size() == 2 && "Unexpected number of results");
MIRBuilder.buildOr(OriginalResult, Results[0], Results[1]);
}
break;
}
case G_FCONSTANT: {
// Convert to integer constants, while preserving the binary representation.
auto AsInteger =
MI.getOperand(1).getFPImm()->getValueAPF().bitcastToAPInt();
MIRBuilder.buildConstant(MI.getOperand(0).getReg(),
*ConstantInt::get(Ctx, AsInteger));
break;
}
}
MI.eraseFromParent();
return true;
}