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//===- RDFRegisters.cpp ---------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "RDFRegisters.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/MC/LaneBitmask.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <cstdint>
#include <set>
#include <utility>
using namespace llvm;
using namespace rdf;
PhysicalRegisterInfo::PhysicalRegisterInfo(const TargetRegisterInfo &tri,
const MachineFunction &mf)
: TRI(tri) {
RegInfos.resize(TRI.getNumRegs());
BitVector BadRC(TRI.getNumRegs());
for (const TargetRegisterClass *RC : TRI.regclasses()) {
for (MCPhysReg R : *RC) {
RegInfo &RI = RegInfos[R];
if (RI.RegClass != nullptr && !BadRC[R]) {
if (RC->LaneMask != RI.RegClass->LaneMask) {
BadRC.set(R);
RI.RegClass = nullptr;
}
} else
RI.RegClass = RC;
}
}
UnitInfos.resize(TRI.getNumRegUnits());
for (uint32_t U = 0, NU = TRI.getNumRegUnits(); U != NU; ++U) {
if (UnitInfos[U].Reg != 0)
continue;
MCRegUnitRootIterator R(U, &TRI);
assert(R.isValid());
RegisterId F = *R;
++R;
if (R.isValid()) {
UnitInfos[U].Mask = LaneBitmask::getAll();
UnitInfos[U].Reg = F;
} else {
for (MCRegUnitMaskIterator I(F, &TRI); I.isValid(); ++I) {
std::pair<uint32_t,LaneBitmask> P = *I;
UnitInfo &UI = UnitInfos[P.first];
UI.Reg = F;
if (P.second.any()) {
UI.Mask = P.second;
} else {
if (const TargetRegisterClass *RC = RegInfos[F].RegClass)
UI.Mask = RC->LaneMask;
else
UI.Mask = LaneBitmask::getAll();
}
}
}
}
for (const uint32_t *RM : TRI.getRegMasks())
RegMasks.insert(RM);
for (const MachineBasicBlock &B : mf)
for (const MachineInstr &In : B)
for (const MachineOperand &Op : In.operands())
if (Op.isRegMask())
RegMasks.insert(Op.getRegMask());
MaskInfos.resize(RegMasks.size()+1);
for (uint32_t M = 1, NM = RegMasks.size(); M <= NM; ++M) {
BitVector PU(TRI.getNumRegUnits());
const uint32_t *MB = RegMasks.get(M);
for (unsigned i = 1, e = TRI.getNumRegs(); i != e; ++i) {
if (!(MB[i/32] & (1u << (i%32))))
continue;
for (MCRegUnitIterator U(i, &TRI); U.isValid(); ++U)
PU.set(*U);
}
MaskInfos[M].Units = PU.flip();
}
}
RegisterRef PhysicalRegisterInfo::normalize(RegisterRef RR) const {
return RR;
}
std::set<RegisterId> PhysicalRegisterInfo::getAliasSet(RegisterId Reg) const {
// Do not include RR in the alias set.
std::set<RegisterId> AS;
assert(isRegMaskId(Reg) || Register::isPhysicalRegister(Reg));
if (isRegMaskId(Reg)) {
// XXX SLOW
const uint32_t *MB = getRegMaskBits(Reg);
for (unsigned i = 1, e = TRI.getNumRegs(); i != e; ++i) {
if (MB[i/32] & (1u << (i%32)))
continue;
AS.insert(i);
}
for (const uint32_t *RM : RegMasks) {
RegisterId MI = getRegMaskId(RM);
if (MI != Reg && aliasMM(RegisterRef(Reg), RegisterRef(MI)))
AS.insert(MI);
}
return AS;
}
for (MCRegAliasIterator AI(Reg, &TRI, false); AI.isValid(); ++AI)
AS.insert(*AI);
for (const uint32_t *RM : RegMasks) {
RegisterId MI = getRegMaskId(RM);
if (aliasRM(RegisterRef(Reg), RegisterRef(MI)))
AS.insert(MI);
}
return AS;
}
bool PhysicalRegisterInfo::aliasRR(RegisterRef RA, RegisterRef RB) const {
assert(Register::isPhysicalRegister(RA.Reg));
assert(Register::isPhysicalRegister(RB.Reg));
MCRegUnitMaskIterator UMA(RA.Reg, &TRI);
MCRegUnitMaskIterator UMB(RB.Reg, &TRI);
// Reg units are returned in the numerical order.
while (UMA.isValid() && UMB.isValid()) {
// Skip units that are masked off in RA.
std::pair<RegisterId,LaneBitmask> PA = *UMA;
if (PA.second.any() && (PA.second & RA.Mask).none()) {
++UMA;
continue;
}
// Skip units that are masked off in RB.
std::pair<RegisterId,LaneBitmask> PB = *UMB;
if (PB.second.any() && (PB.second & RB.Mask).none()) {
++UMB;
continue;
}
if (PA.first == PB.first)
return true;
if (PA.first < PB.first)
++UMA;
else if (PB.first < PA.first)
++UMB;
}
return false;
}
bool PhysicalRegisterInfo::aliasRM(RegisterRef RR, RegisterRef RM) const {
assert(Register::isPhysicalRegister(RR.Reg) && isRegMaskId(RM.Reg));
const uint32_t *MB = getRegMaskBits(RM.Reg);
bool Preserved = MB[RR.Reg/32] & (1u << (RR.Reg%32));
// If the lane mask information is "full", e.g. when the given lane mask
// is a superset of the lane mask from the register class, check the regmask
// bit directly.
if (RR.Mask == LaneBitmask::getAll())
return !Preserved;
const TargetRegisterClass *RC = RegInfos[RR.Reg].RegClass;
if (RC != nullptr && (RR.Mask & RC->LaneMask) == RC->LaneMask)
return !Preserved;
// Otherwise, check all subregisters whose lane mask overlaps the given
// mask. For each such register, if it is preserved by the regmask, then
// clear the corresponding bits in the given mask. If at the end, all
// bits have been cleared, the register does not alias the regmask (i.e.
// is it preserved by it).
LaneBitmask M = RR.Mask;
for (MCSubRegIndexIterator SI(RR.Reg, &TRI); SI.isValid(); ++SI) {
LaneBitmask SM = TRI.getSubRegIndexLaneMask(SI.getSubRegIndex());
if ((SM & RR.Mask).none())
continue;
unsigned SR = SI.getSubReg();
if (!(MB[SR/32] & (1u << (SR%32))))
continue;
// The subregister SR is preserved.
M &= ~SM;
if (M.none())
return false;
}
return true;
}
bool PhysicalRegisterInfo::aliasMM(RegisterRef RM, RegisterRef RN) const {
assert(isRegMaskId(RM.Reg) && isRegMaskId(RN.Reg));
unsigned NumRegs = TRI.getNumRegs();
const uint32_t *BM = getRegMaskBits(RM.Reg);
const uint32_t *BN = getRegMaskBits(RN.Reg);
for (unsigned w = 0, nw = NumRegs/32; w != nw; ++w) {
// Intersect the negations of both words. Disregard reg=0,
// i.e. 0th bit in the 0th word.
uint32_t C = ~BM[w] & ~BN[w];
if (w == 0)
C &= ~1;
if (C)
return true;
}
// Check the remaining registers in the last word.
unsigned TailRegs = NumRegs % 32;
if (TailRegs == 0)
return false;
unsigned TW = NumRegs / 32;
uint32_t TailMask = (1u << TailRegs) - 1;
if (~BM[TW] & ~BN[TW] & TailMask)
return true;
return false;
}
RegisterRef PhysicalRegisterInfo::mapTo(RegisterRef RR, unsigned R) const {
if (RR.Reg == R)
return RR;
if (unsigned Idx = TRI.getSubRegIndex(R, RR.Reg))
return RegisterRef(R, TRI.composeSubRegIndexLaneMask(Idx, RR.Mask));
if (unsigned Idx = TRI.getSubRegIndex(RR.Reg, R)) {
const RegInfo &RI = RegInfos[R];
LaneBitmask RCM = RI.RegClass ? RI.RegClass->LaneMask
: LaneBitmask::getAll();
LaneBitmask M = TRI.reverseComposeSubRegIndexLaneMask(Idx, RR.Mask);
return RegisterRef(R, M & RCM);
}
llvm_unreachable("Invalid arguments: unrelated registers?");
}
bool RegisterAggr::hasAliasOf(RegisterRef RR) const {
if (PhysicalRegisterInfo::isRegMaskId(RR.Reg))
return Units.anyCommon(PRI.getMaskUnits(RR.Reg));
for (MCRegUnitMaskIterator U(RR.Reg, &PRI.getTRI()); U.isValid(); ++U) {
std::pair<uint32_t,LaneBitmask> P = *U;
if (P.second.none() || (P.second & RR.Mask).any())
if (Units.test(P.first))
return true;
}
return false;
}
bool RegisterAggr::hasCoverOf(RegisterRef RR) const {
if (PhysicalRegisterInfo::isRegMaskId(RR.Reg)) {
BitVector T(PRI.getMaskUnits(RR.Reg));
return T.reset(Units).none();
}
for (MCRegUnitMaskIterator U(RR.Reg, &PRI.getTRI()); U.isValid(); ++U) {
std::pair<uint32_t,LaneBitmask> P = *U;
if (P.second.none() || (P.second & RR.Mask).any())
if (!Units.test(P.first))
return false;
}
return true;
}
RegisterAggr &RegisterAggr::insert(RegisterRef RR) {
if (PhysicalRegisterInfo::isRegMaskId(RR.Reg)) {
Units |= PRI.getMaskUnits(RR.Reg);
return *this;
}
for (MCRegUnitMaskIterator U(RR.Reg, &PRI.getTRI()); U.isValid(); ++U) {
std::pair<uint32_t,LaneBitmask> P = *U;
if (P.second.none() || (P.second & RR.Mask).any())
Units.set(P.first);
}
return *this;
}
RegisterAggr &RegisterAggr::insert(const RegisterAggr &RG) {
Units |= RG.Units;
return *this;
}
RegisterAggr &RegisterAggr::intersect(RegisterRef RR) {
return intersect(RegisterAggr(PRI).insert(RR));
}
RegisterAggr &RegisterAggr::intersect(const RegisterAggr &RG) {
Units &= RG.Units;
return *this;
}
RegisterAggr &RegisterAggr::clear(RegisterRef RR) {
return clear(RegisterAggr(PRI).insert(RR));
}
RegisterAggr &RegisterAggr::clear(const RegisterAggr &RG) {
Units.reset(RG.Units);
return *this;
}
RegisterRef RegisterAggr::intersectWith(RegisterRef RR) const {
RegisterAggr T(PRI);
T.insert(RR).intersect(*this);
if (T.empty())
return RegisterRef();
RegisterRef NR = T.makeRegRef();
assert(NR);
return NR;
}
RegisterRef RegisterAggr::clearIn(RegisterRef RR) const {
return RegisterAggr(PRI).insert(RR).clear(*this).makeRegRef();
}
RegisterRef RegisterAggr::makeRegRef() const {
int U = Units.find_first();
if (U < 0)
return RegisterRef();
auto AliasedRegs = [this] (uint32_t Unit, BitVector &Regs) {
for (MCRegUnitRootIterator R(Unit, &PRI.getTRI()); R.isValid(); ++R)
for (MCSuperRegIterator S(*R, &PRI.getTRI(), true); S.isValid(); ++S)
Regs.set(*S);
};
// Find the set of all registers that are aliased to all the units
// in this aggregate.
// Get all the registers aliased to the first unit in the bit vector.
BitVector Regs(PRI.getTRI().getNumRegs());
AliasedRegs(U, Regs);
U = Units.find_next(U);
// For each other unit, intersect it with the set of all registers
// aliased that unit.
while (U >= 0) {
BitVector AR(PRI.getTRI().getNumRegs());
AliasedRegs(U, AR);
Regs &= AR;
U = Units.find_next(U);
}
// If there is at least one register remaining, pick the first one,
// and consolidate the masks of all of its units contained in this
// aggregate.
int F = Regs.find_first();
if (F <= 0)
return RegisterRef();
LaneBitmask M;
for (MCRegUnitMaskIterator I(F, &PRI.getTRI()); I.isValid(); ++I) {
std::pair<uint32_t,LaneBitmask> P = *I;
if (Units.test(P.first))
M |= P.second.none() ? LaneBitmask::getAll() : P.second;
}
return RegisterRef(F, M);
}
void RegisterAggr::print(raw_ostream &OS) const {
OS << '{';
for (int U = Units.find_first(); U >= 0; U = Units.find_next(U))
OS << ' ' << printRegUnit(U, &PRI.getTRI());
OS << " }";
}
RegisterAggr::rr_iterator::rr_iterator(const RegisterAggr &RG,
bool End)
: Owner(&RG) {
for (int U = RG.Units.find_first(); U >= 0; U = RG.Units.find_next(U)) {
RegisterRef R = RG.PRI.getRefForUnit(U);
Masks[R.Reg] |= R.Mask;
}
Pos = End ? Masks.end() : Masks.begin();
Index = End ? Masks.size() : 0;
}