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llvm-project/llvm/lib/Target/Hexagon/HexagonBlockRanges.cpp

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//===- HexagonBlockRanges.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 "HexagonBlockRanges.h"
#include "HexagonInstrInfo.h"
#include "HexagonSubtarget.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <iterator>
#include <map>
#include <utility>
using namespace llvm;
#define DEBUG_TYPE "hbr"
bool HexagonBlockRanges::IndexRange::overlaps(const IndexRange &A) const {
// If A contains start(), or "this" contains A.start(), then overlap.
IndexType S = start(), E = end(), AS = A.start(), AE = A.end();
if (AS == S)
return true;
bool SbAE = (S < AE) || (S == AE && A.TiedEnd); // S-before-AE.
bool ASbE = (AS < E) || (AS == E && TiedEnd); // AS-before-E.
if ((AS < S && SbAE) || (S < AS && ASbE))
return true;
// Otherwise no overlap.
return false;
}
bool HexagonBlockRanges::IndexRange::contains(const IndexRange &A) const {
if (start() <= A.start()) {
// Treat "None" in the range end as equal to the range start.
IndexType E = (end() != IndexType::None) ? end() : start();
IndexType AE = (A.end() != IndexType::None) ? A.end() : A.start();
if (AE <= E)
return true;
}
return false;
}
void HexagonBlockRanges::IndexRange::merge(const IndexRange &A) {
// Allow merging adjacent ranges.
assert(end() == A.start() || overlaps(A));
IndexType AS = A.start(), AE = A.end();
if (AS < start() || start() == IndexType::None)
setStart(AS);
if (end() < AE || end() == IndexType::None) {
setEnd(AE);
TiedEnd = A.TiedEnd;
} else {
if (end() == AE)
TiedEnd |= A.TiedEnd;
}
if (A.Fixed)
Fixed = true;
}
void HexagonBlockRanges::RangeList::include(const RangeList &RL) {
for (auto &R : RL)
if (!is_contained(*this, R))
push_back(R);
}
// Merge all overlapping ranges in the list, so that all that remains
// is a list of disjoint ranges.
void HexagonBlockRanges::RangeList::unionize(bool MergeAdjacent) {
if (empty())
return;
llvm::sort(begin(), end());
iterator Iter = begin();
while (Iter != end()-1) {
iterator Next = std::next(Iter);
// If MergeAdjacent is true, merge ranges A and B, where A.end == B.start.
// This allows merging dead ranges, but is not valid for live ranges.
bool Merge = MergeAdjacent && (Iter->end() == Next->start());
if (Merge || Iter->overlaps(*Next)) {
Iter->merge(*Next);
erase(Next);
continue;
}
++Iter;
}
}
// Compute a range A-B and add it to the list.
void HexagonBlockRanges::RangeList::addsub(const IndexRange &A,
const IndexRange &B) {
// Exclusion of non-overlapping ranges makes some checks simpler
// later in this function.
if (!A.overlaps(B)) {
// A - B = A.
add(A);
return;
}
IndexType AS = A.start(), AE = A.end();
IndexType BS = B.start(), BE = B.end();
// If AE is None, then A is included in B, since A and B overlap.
// The result of subtraction if empty, so just return.
if (AE == IndexType::None)
return;
if (AS < BS) {
// A starts before B.
// AE cannot be None since A and B overlap.
assert(AE != IndexType::None);
// Add the part of A that extends on the "less" side of B.
add(AS, BS, A.Fixed, false);
}
if (BE < AE) {
// BE cannot be Exit here.
if (BE == IndexType::None)
add(BS, AE, A.Fixed, false);
else
add(BE, AE, A.Fixed, false);
}
}
// Subtract a given range from each element in the list.
void HexagonBlockRanges::RangeList::subtract(const IndexRange &Range) {
// Cannot assume that the list is unionized (i.e. contains only non-
// overlapping ranges.
RangeList T;
for (iterator Next, I = begin(); I != end(); I = Next) {
IndexRange &Rg = *I;
if (Rg.overlaps(Range)) {
T.addsub(Rg, Range);
Next = this->erase(I);
} else {
Next = std::next(I);
}
}
include(T);
}
HexagonBlockRanges::InstrIndexMap::InstrIndexMap(MachineBasicBlock &B)
: Block(B) {
IndexType Idx = IndexType::First;
First = Idx;
for (auto &In : B) {
if (In.isDebugInstr())
continue;
assert(getIndex(&In) == IndexType::None && "Instruction already in map");
Map.insert(std::make_pair(Idx, &In));
++Idx;
}
Last = B.empty() ? IndexType::None : unsigned(Idx)-1;
}
MachineInstr *HexagonBlockRanges::InstrIndexMap::getInstr(IndexType Idx) const {
auto F = Map.find(Idx);
return (F != Map.end()) ? F->second : nullptr;
}
HexagonBlockRanges::IndexType HexagonBlockRanges::InstrIndexMap::getIndex(
MachineInstr *MI) const {
for (auto &I : Map)
if (I.second == MI)
return I.first;
return IndexType::None;
}
HexagonBlockRanges::IndexType HexagonBlockRanges::InstrIndexMap::getPrevIndex(
IndexType Idx) const {
assert (Idx != IndexType::None);
if (Idx == IndexType::Entry)
return IndexType::None;
if (Idx == IndexType::Exit)
return Last;
if (Idx == First)
return IndexType::Entry;
return unsigned(Idx)-1;
}
HexagonBlockRanges::IndexType HexagonBlockRanges::InstrIndexMap::getNextIndex(
IndexType Idx) const {
assert (Idx != IndexType::None);
if (Idx == IndexType::Entry)
return IndexType::First;
if (Idx == IndexType::Exit || Idx == Last)
return IndexType::None;
return unsigned(Idx)+1;
}
void HexagonBlockRanges::InstrIndexMap::replaceInstr(MachineInstr *OldMI,
MachineInstr *NewMI) {
for (auto &I : Map) {
if (I.second != OldMI)
continue;
if (NewMI != nullptr)
I.second = NewMI;
else
Map.erase(I.first);
break;
}
}
HexagonBlockRanges::HexagonBlockRanges(MachineFunction &mf)
: MF(mf), HST(mf.getSubtarget<HexagonSubtarget>()),
TII(*HST.getInstrInfo()), TRI(*HST.getRegisterInfo()),
Reserved(TRI.getReservedRegs(mf)) {
// Consider all non-allocatable registers as reserved.
for (const TargetRegisterClass *RC : TRI.regclasses()) {
if (RC->isAllocatable())
continue;
for (unsigned R : *RC)
Reserved[R] = true;
}
}
HexagonBlockRanges::RegisterSet HexagonBlockRanges::getLiveIns(
const MachineBasicBlock &B, const MachineRegisterInfo &MRI,
const TargetRegisterInfo &TRI) {
RegisterSet LiveIns;
RegisterSet Tmp;
for (auto I : B.liveins()) {
MCSubRegIndexIterator S(I.PhysReg, &TRI);
if (I.LaneMask.all() || (I.LaneMask.any() && !S.isValid())) {
Tmp.insert({I.PhysReg, 0});
continue;
}
for (; S.isValid(); ++S) {
unsigned SI = S.getSubRegIndex();
if ((I.LaneMask & TRI.getSubRegIndexLaneMask(SI)).any())
Tmp.insert({S.getSubReg(), 0});
}
}
for (auto R : Tmp) {
if (!Reserved[R.Reg])
LiveIns.insert(R);
for (auto S : expandToSubRegs(R, MRI, TRI))
if (!Reserved[S.Reg])
LiveIns.insert(S);
}
return LiveIns;
}
HexagonBlockRanges::RegisterSet HexagonBlockRanges::expandToSubRegs(
RegisterRef R, const MachineRegisterInfo &MRI,
const TargetRegisterInfo &TRI) {
RegisterSet SRs;
if (R.Sub != 0) {
SRs.insert(R);
return SRs;
}
if (Register::isPhysicalRegister(R.Reg)) {
MCSubRegIterator I(R.Reg, &TRI);
if (!I.isValid())
SRs.insert({R.Reg, 0});
for (; I.isValid(); ++I)
SRs.insert({*I, 0});
} else {
assert(R.Reg.isVirtual());
auto &RC = *MRI.getRegClass(R.Reg);
unsigned PReg = *RC.begin();
MCSubRegIndexIterator I(PReg, &TRI);
if (!I.isValid())
SRs.insert({R.Reg, 0});
for (; I.isValid(); ++I)
SRs.insert({R.Reg, I.getSubRegIndex()});
}
return SRs;
}
void HexagonBlockRanges::computeInitialLiveRanges(InstrIndexMap &IndexMap,
RegToRangeMap &LiveMap) {
std::map<RegisterRef,IndexType> LastDef, LastUse;
RegisterSet LiveOnEntry;
MachineBasicBlock &B = IndexMap.getBlock();
MachineRegisterInfo &MRI = B.getParent()->getRegInfo();
for (auto R : getLiveIns(B, MRI, TRI))
LiveOnEntry.insert(R);
for (auto R : LiveOnEntry)
LastDef[R] = IndexType::Entry;
auto closeRange = [&LastUse,&LastDef,&LiveMap] (RegisterRef R) -> void {
auto LD = LastDef[R], LU = LastUse[R];
if (LD == IndexType::None)
LD = IndexType::Entry;
if (LU == IndexType::None)
LU = IndexType::Exit;
LiveMap[R].add(LD, LU, false, false);
LastUse[R] = LastDef[R] = IndexType::None;
};
RegisterSet Defs, Clobbers;
for (auto &In : B) {
if (In.isDebugInstr())
continue;
IndexType Index = IndexMap.getIndex(&In);
// Process uses first.
for (auto &Op : In.operands()) {
if (!Op.isReg() || !Op.isUse() || Op.isUndef())
continue;
RegisterRef R = { Op.getReg(), Op.getSubReg() };
if (Register::isPhysicalRegister(R.Reg) && Reserved[R.Reg])
continue;
bool IsKill = Op.isKill();
for (auto S : expandToSubRegs(R, MRI, TRI)) {
LastUse[S] = Index;
if (IsKill)
closeRange(S);
}
}
// Process defs and clobbers.
Defs.clear();
Clobbers.clear();
for (auto &Op : In.operands()) {
if (!Op.isReg() || !Op.isDef() || Op.isUndef())
continue;
RegisterRef R = { Op.getReg(), Op.getSubReg() };
for (auto S : expandToSubRegs(R, MRI, TRI)) {
if (Register::isPhysicalRegister(S.Reg) && Reserved[S.Reg])
continue;
if (Op.isDead())
Clobbers.insert(S);
else
Defs.insert(S);
}
}
for (auto &Op : In.operands()) {
if (!Op.isRegMask())
continue;
const uint32_t *BM = Op.getRegMask();
for (unsigned PR = 1, N = TRI.getNumRegs(); PR != N; ++PR) {
// Skip registers that have subregisters. A register is preserved
// iff its bit is set in the regmask, so if R1:0 was preserved, both
// R1 and R0 would also be present.
if (MCSubRegIterator(PR, &TRI, false).isValid())
continue;
if (Reserved[PR])
continue;
if (BM[PR/32] & (1u << (PR%32)))
continue;
RegisterRef R = { PR, 0 };
if (!Defs.count(R))
Clobbers.insert(R);
}
}
// Defs and clobbers can overlap, e.g.
// dead %d0 = COPY %5, implicit-def %r0, implicit-def %r1
for (RegisterRef R : Defs)
Clobbers.erase(R);
// Update maps for defs.
for (RegisterRef S : Defs) {
// Defs should already be expanded into subregs.
assert(!Register::isPhysicalRegister(S.Reg) ||
!MCSubRegIterator(S.Reg, &TRI, false).isValid());
if (LastDef[S] != IndexType::None || LastUse[S] != IndexType::None)
closeRange(S);
LastDef[S] = Index;
}
// Update maps for clobbers.
for (RegisterRef S : Clobbers) {
// Clobbers should already be expanded into subregs.
assert(!Register::isPhysicalRegister(S.Reg) ||
!MCSubRegIterator(S.Reg, &TRI, false).isValid());
if (LastDef[S] != IndexType::None || LastUse[S] != IndexType::None)
closeRange(S);
// Create a single-instruction range.
LastDef[S] = LastUse[S] = Index;
closeRange(S);
}
}
// Collect live-on-exit.
RegisterSet LiveOnExit;
for (auto *SB : B.successors())
for (auto R : getLiveIns(*SB, MRI, TRI))
LiveOnExit.insert(R);
for (auto R : LiveOnExit)
LastUse[R] = IndexType::Exit;
// Process remaining registers.
RegisterSet Left;
for (auto &I : LastUse)
if (I.second != IndexType::None)
Left.insert(I.first);
for (auto &I : LastDef)
if (I.second != IndexType::None)
Left.insert(I.first);
for (auto R : Left)
closeRange(R);
// Finalize the live ranges.
for (auto &P : LiveMap)
P.second.unionize();
}
HexagonBlockRanges::RegToRangeMap HexagonBlockRanges::computeLiveMap(
InstrIndexMap &IndexMap) {
RegToRangeMap LiveMap;
LLVM_DEBUG(dbgs() << __func__ << ": index map\n" << IndexMap << '\n');
computeInitialLiveRanges(IndexMap, LiveMap);
LLVM_DEBUG(dbgs() << __func__ << ": live map\n"
<< PrintRangeMap(LiveMap, TRI) << '\n');
return LiveMap;
}
HexagonBlockRanges::RegToRangeMap HexagonBlockRanges::computeDeadMap(
InstrIndexMap &IndexMap, RegToRangeMap &LiveMap) {
RegToRangeMap DeadMap;
auto addDeadRanges = [&IndexMap,&LiveMap,&DeadMap] (RegisterRef R) -> void {
auto F = LiveMap.find(R);
if (F == LiveMap.end() || F->second.empty()) {
DeadMap[R].add(IndexType::Entry, IndexType::Exit, false, false);
return;
}
RangeList &RL = F->second;
RangeList::iterator A = RL.begin(), Z = RL.end()-1;
// Try to create the initial range.
if (A->start() != IndexType::Entry) {
IndexType DE = IndexMap.getPrevIndex(A->start());
if (DE != IndexType::Entry)
DeadMap[R].add(IndexType::Entry, DE, false, false);
}
while (A != Z) {
// Creating a dead range that follows A. Pay attention to empty
// ranges (i.e. those ending with "None").
IndexType AE = (A->end() == IndexType::None) ? A->start() : A->end();
IndexType DS = IndexMap.getNextIndex(AE);
++A;
IndexType DE = IndexMap.getPrevIndex(A->start());
if (DS < DE)
DeadMap[R].add(DS, DE, false, false);
}
// Try to create the final range.
if (Z->end() != IndexType::Exit) {
IndexType ZE = (Z->end() == IndexType::None) ? Z->start() : Z->end();
IndexType DS = IndexMap.getNextIndex(ZE);
if (DS < IndexType::Exit)
DeadMap[R].add(DS, IndexType::Exit, false, false);
}
};
MachineFunction &MF = *IndexMap.getBlock().getParent();
auto &MRI = MF.getRegInfo();
unsigned NumRegs = TRI.getNumRegs();
BitVector Visited(NumRegs);
for (unsigned R = 1; R < NumRegs; ++R) {
for (auto S : expandToSubRegs({R,0}, MRI, TRI)) {
if (Reserved[S.Reg] || Visited[S.Reg])
continue;
addDeadRanges(S);
Visited[S.Reg] = true;
}
}
for (auto &P : LiveMap)
if (P.first.Reg.isVirtual())
addDeadRanges(P.first);
LLVM_DEBUG(dbgs() << __func__ << ": dead map\n"
<< PrintRangeMap(DeadMap, TRI) << '\n');
return DeadMap;
}
raw_ostream &llvm::operator<<(raw_ostream &OS,
HexagonBlockRanges::IndexType Idx) {
if (Idx == HexagonBlockRanges::IndexType::None)
return OS << '-';
if (Idx == HexagonBlockRanges::IndexType::Entry)
return OS << 'n';
if (Idx == HexagonBlockRanges::IndexType::Exit)
return OS << 'x';
return OS << unsigned(Idx)-HexagonBlockRanges::IndexType::First+1;
}
// A mapping to translate between instructions and their indices.
raw_ostream &llvm::operator<<(raw_ostream &OS,
const HexagonBlockRanges::IndexRange &IR) {
OS << '[' << IR.start() << ':' << IR.end() << (IR.TiedEnd ? '}' : ']');
if (IR.Fixed)
OS << '!';
return OS;
}
raw_ostream &llvm::operator<<(raw_ostream &OS,
const HexagonBlockRanges::RangeList &RL) {
for (auto &R : RL)
OS << R << " ";
return OS;
}
raw_ostream &llvm::operator<<(raw_ostream &OS,
const HexagonBlockRanges::InstrIndexMap &M) {
for (auto &In : M.Block) {
HexagonBlockRanges::IndexType Idx = M.getIndex(&In);
OS << Idx << (Idx == M.Last ? ". " : " ") << In;
}
return OS;
}
raw_ostream &llvm::operator<<(raw_ostream &OS,
const HexagonBlockRanges::PrintRangeMap &P) {
for (auto &I : P.Map) {
const HexagonBlockRanges::RangeList &RL = I.second;
OS << printReg(I.first.Reg, &P.TRI, I.first.Sub) << " -> " << RL << "\n";
}
return OS;
}
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