#include "llvm/CodeGen/Passes.h"
#include "llvm/ADT/PostOrderIterator.h"
+#include "llvm/ADT/iterator_range.h"
#include "llvm/CodeGen/LivePhysRegs.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
// Is domain available?
bool hasDomain(unsigned domain) const {
+ assert(domain <
+ static_cast<unsigned>(std::numeric_limits<unsigned>::digits) &&
+ "undefined behavior");
return AvailableDomains & (1u << domain);
}
}
namespace {
-/// LiveReg - Information about a live register.
+/// Information about a live register.
struct LiveReg {
/// Value currently in this register, or NULL when no value is being tracked.
/// This counts as a DomainValue reference.
/// will be a negative number.
int Def;
};
-} // anonynous namespace
+} // anonymous namespace
namespace {
class ExeDepsFix : public MachineFunctionPass {
MachineFunction *MF;
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
- std::vector<int> AliasMap;
+ std::vector<SmallVector<int, 1>> AliasMap;
const unsigned NumRegs;
LiveReg *LiveRegs;
typedef DenseMap<MachineBasicBlock*, LiveReg*> LiveOutMap;
}
private:
- // Register mapping.
- int regIndex(unsigned Reg);
+ iterator_range<SmallVectorImpl<int>::const_iterator>
+ regIndices(unsigned Reg) const;
// DomainValue allocation.
DomainValue *alloc(int domain = -1);
char ExeDepsFix::ID = 0;
-/// Translate TRI register number to an index into our smaller tables of
-/// interesting registers. Return -1 for boring registers.
-int ExeDepsFix::regIndex(unsigned Reg) {
+/// Translate TRI register number to a list of indices into our smaller tables
+/// of interesting registers.
+iterator_range<SmallVectorImpl<int>::const_iterator>
+ExeDepsFix::regIndices(unsigned Reg) const {
assert(Reg < AliasMap.size() && "Invalid register");
- return AliasMap[Reg];
+ const auto &Entry = AliasMap[Reg];
+ return make_range(Entry.begin(), Entry.end());
}
DomainValue *ExeDepsFix::alloc(int domain) {
return dv;
}
-/// release - Release a reference to DV. When the last reference is released,
+/// Release a reference to DV. When the last reference is released,
/// collapse if needed.
void ExeDepsFix::release(DomainValue *DV) {
while (DV) {
}
}
-/// resolve - Follow the chain of dead DomainValues until a live DomainValue is
-/// reached. Update the referenced pointer when necessary.
+/// Follow the chain of dead DomainValues until a live DomainValue is reached.
+/// Update the referenced pointer when necessary.
DomainValue *ExeDepsFix::resolve(DomainValue *&DVRef) {
DomainValue *DV = DVRef;
if (!DV || !DV->Next)
setLiveReg(rx, alloc(domain));
}
-/// Merge - All instructions and registers in B are moved to A, and B is
-/// released.
+/// All instructions and registers in B are moved to A, and B is released.
bool ExeDepsFix::merge(DomainValue *A, DomainValue *B) {
assert(!A->isCollapsed() && "Cannot merge into collapsed");
assert(!B->isCollapsed() && "Cannot merge from collapsed");
// All uses of B are referred to A.
B->Next = retain(A);
- for (unsigned rx = 0; rx != NumRegs; ++rx)
+ for (unsigned rx = 0; rx != NumRegs; ++rx) {
+ assert(LiveRegs && "no space allocated for live registers");
if (LiveRegs[rx].Value == B)
setLiveReg(rx, A);
+ }
return true;
}
-// enterBasicBlock - Set up LiveRegs by merging predecessor live-out values.
+/// Set up LiveRegs by merging predecessor live-out values.
void ExeDepsFix::enterBasicBlock(MachineBasicBlock *MBB) {
// Detect back-edges from predecessors we haven't processed yet.
SeenUnknownBackEdge = false;
if (MBB->pred_empty()) {
for (MachineBasicBlock::livein_iterator i = MBB->livein_begin(),
e = MBB->livein_end(); i != e; ++i) {
- int rx = regIndex(*i);
- if (rx < 0)
- continue;
- // Treat function live-ins as if they were defined just before the first
- // instruction. Usually, function arguments are set up immediately
- // before the call.
- LiveRegs[rx].Def = -1;
+ for (int rx : regIndices(*i)) {
+ // Treat function live-ins as if they were defined just before the first
+ // instruction. Usually, function arguments are set up immediately
+ // before the call.
+ LiveRegs[rx].Def = -1;
+ }
}
DEBUG(dbgs() << "BB#" << MBB->getNumber() << ": entry\n");
return;
/// or undef use.
bool ExeDepsFix::shouldBreakDependence(MachineInstr *MI, unsigned OpIdx,
unsigned Pref) {
- int rx = regIndex(MI->getOperand(OpIdx).getReg());
- if (rx < 0)
- return false;
-
- unsigned Clearance = CurInstr - LiveRegs[rx].Def;
- DEBUG(dbgs() << "Clearance: " << Clearance << ", want " << Pref);
+ unsigned reg = MI->getOperand(OpIdx).getReg();
+ for (int rx : regIndices(reg)) {
+ unsigned Clearance = CurInstr - LiveRegs[rx].Def;
+ DEBUG(dbgs() << "Clearance: " << Clearance << ", want " << Pref);
- if (Pref > Clearance) {
- DEBUG(dbgs() << ": Break dependency.\n");
- return true;
- }
- // The current clearance seems OK, but we may be ignoring a def from a
- // back-edge.
- if (!SeenUnknownBackEdge || Pref <= unsigned(CurInstr)) {
- DEBUG(dbgs() << ": OK .\n");
+ if (Pref > Clearance) {
+ DEBUG(dbgs() << ": Break dependency.\n");
+ continue;
+ }
+ // The current clearance seems OK, but we may be ignoring a def from a
+ // back-edge.
+ if (!SeenUnknownBackEdge || Pref <= unsigned(CurInstr)) {
+ DEBUG(dbgs() << ": OK .\n");
+ return false;
+ }
+ // A def from an unprocessed back-edge may make us break this dependency.
+ DEBUG(dbgs() << ": Wait for back-edge to resolve.\n");
return false;
}
- // A def from an unprocessed back-edge may make us break this dependency.
- DEBUG(dbgs() << ": Wait for back-edge to resolve.\n");
- return false;
+ return true;
}
// Update def-ages for registers defined by MI.
break;
if (MO.isUse())
continue;
- int rx = regIndex(MO.getReg());
- if (rx < 0)
- continue;
-
- // This instruction explicitly defines rx.
- DEBUG(dbgs() << TRI->getName(RC->getRegister(rx)) << ":\t" << CurInstr
- << '\t' << *MI);
-
- // Check clearance before partial register updates.
- // Call breakDependence before setting LiveRegs[rx].Def.
- unsigned Pref = TII->getPartialRegUpdateClearance(MI, i, TRI);
- if (Pref && shouldBreakDependence(MI, i, Pref))
- TII->breakPartialRegDependency(MI, i, TRI);
-
- // How many instructions since rx was last written?
- LiveRegs[rx].Def = CurInstr;
-
- // Kill off domains redefined by generic instructions.
- if (Kill)
- kill(rx);
+ for (int rx : regIndices(MO.getReg())) {
+ // This instruction explicitly defines rx.
+ DEBUG(dbgs() << TRI->getName(RC->getRegister(rx)) << ":\t" << CurInstr
+ << '\t' << *MI);
+
+ // Check clearance before partial register updates.
+ // Call breakDependence before setting LiveRegs[rx].Def.
+ unsigned Pref = TII->getPartialRegUpdateClearance(MI, i, TRI);
+ if (Pref && shouldBreakDependence(MI, i, Pref))
+ TII->breakPartialRegDependency(MI, i, TRI);
+
+ // How many instructions since rx was last written?
+ LiveRegs[rx].Def = CurInstr;
+
+ // Kill off domains redefined by generic instructions.
+ if (Kill)
+ kill(rx);
+ }
}
++CurInstr;
}
e = mi->getDesc().getNumOperands(); i != e; ++i) {
MachineOperand &mo = mi->getOperand(i);
if (!mo.isReg()) continue;
- int rx = regIndex(mo.getReg());
- if (rx < 0) continue;
- force(rx, domain);
+ for (int rx : regIndices(mo.getReg())) {
+ force(rx, domain);
+ }
}
// Kill all defs and force them.
for (unsigned i = 0, e = mi->getDesc().getNumDefs(); i != e; ++i) {
MachineOperand &mo = mi->getOperand(i);
if (!mo.isReg()) continue;
- int rx = regIndex(mo.getReg());
- if (rx < 0) continue;
- kill(rx);
- force(rx, domain);
+ for (int rx : regIndices(mo.getReg())) {
+ kill(rx);
+ force(rx, domain);
+ }
}
}
e = mi->getDesc().getNumOperands(); i != e; ++i) {
MachineOperand &mo = mi->getOperand(i);
if (!mo.isReg()) continue;
- int rx = regIndex(mo.getReg());
- if (rx < 0) continue;
- if (DomainValue *dv = LiveRegs[rx].Value) {
+ for (int rx : regIndices(mo.getReg())) {
+ DomainValue *dv = LiveRegs[rx].Value;
+ if (dv == nullptr)
+ continue;
// Bitmask of domains that dv and available have in common.
unsigned common = dv->getCommonDomains(available);
// Is it possible to use this collapsed register for free?
SmallVector<LiveReg, 4> Regs;
for (SmallVectorImpl<int>::iterator i=used.begin(), e=used.end(); i!=e; ++i) {
int rx = *i;
+ assert(LiveRegs && "no space allocated for live registers");
const LiveReg &LR = LiveRegs[rx];
// This useless DomainValue could have been missed above.
if (!LR.Value->getCommonDomains(available)) {
continue;
// If latest didn't merge, it is useless now. Kill all registers using it.
- for (SmallVectorImpl<int>::iterator i=used.begin(), e=used.end(); i!=e; ++i)
- if (LiveRegs[*i].Value == Latest)
- kill(*i);
+ for (int i : used) {
+ assert(LiveRegs && "no space allocated for live registers");
+ if (LiveRegs[i].Value == Latest)
+ kill(i);
+ }
}
// dv is the DomainValue we are going to use for this instruction.
ii != ee; ++ii) {
MachineOperand &mo = *ii;
if (!mo.isReg()) continue;
- int rx = regIndex(mo.getReg());
- if (rx < 0) continue;
- if (!LiveRegs[rx].Value || (mo.isDef() && LiveRegs[rx].Value != dv)) {
- kill(rx);
- setLiveReg(rx, dv);
+ for (int rx : regIndices(mo.getReg())) {
+ if (!LiveRegs[rx].Value || (mo.isDef() && LiveRegs[rx].Value != dv)) {
+ kill(rx);
+ setLiveReg(rx, dv);
+ }
}
}
}
assert(NumRegs == RC->getNumRegs() && "Bad regclass");
DEBUG(dbgs() << "********** FIX EXECUTION DEPENDENCIES: "
- << RC->getName() << " **********\n");
+ << TRI->getRegClassName(RC) << " **********\n");
// If no relevant registers are used in the function, we can skip it
// completely.
// Initialize the AliasMap on the first use.
if (AliasMap.empty()) {
- // Given a PhysReg, AliasMap[PhysReg] is either the relevant index into RC,
- // or -1.
- AliasMap.resize(TRI->getNumRegs(), -1);
+ // Given a PhysReg, AliasMap[PhysReg] returns a list of indices into RC and
+ // therefore the LiveRegs array.
+ AliasMap.resize(TRI->getNumRegs());
for (unsigned i = 0, e = RC->getNumRegs(); i != e; ++i)
for (MCRegAliasIterator AI(RC->getRegister(i), TRI, true);
AI.isValid(); ++AI)
- AliasMap[*AI] = i;
+ AliasMap[*AI].push_back(i);
}
MachineBasicBlock *Entry = MF->begin();
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