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[CodeGen] Remove EvictionTrack (NFC) 

The last of getEvictor use was removed on Jun 5, 2022 in commit
5c06f7168f, which was itself a patch to
remove unused code.

Once we remove getEvictor, EvictionTrack becomes a write-only data
structure.  The data in it won't affect compilation, so the entire
class is essentially dead.
This commit is contained in:
Kazu Hirata 2022-06-13 07:21:29 -07:00
parent 35aaf54823
commit 23d9ca10ae
2 changed files with 1 additions and 63 deletions
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13
llvm/lib/CodeGen/RegAllocGreedy.cpp
View File

@ -479,8 +479,6 @@ void RAGreedy::evictInterference(const LiveInterval &VirtReg,
if (!VRM->hasPhys(Intf->reg()))
continue;
LastEvicted.addEviction(PhysReg, VirtReg.reg(), Intf->reg());
Matrix->unassign(*Intf);
assert((ExtraInfo->getCascade(Intf->reg()) < Cascade ||
VirtReg.isSpillable() < Intf->isSpillable()) &&
@ -2235,8 +2233,6 @@ MCRegister RAGreedy::selectOrSplitImpl(const LiveInterval &VirtReg,
AllocationOrder::create(VirtReg.reg(), *VRM, RegClassInfo, Matrix);
if (MCRegister PhysReg =
tryAssign(VirtReg, Order, NewVRegs, FixedRegisters)) {
// If VirtReg got an assignment, the eviction info is no longer relevant.
LastEvicted.clearEvicteeInfo(VirtReg.reg());
// When NewVRegs is not empty, we may have made decisions such as evicting
// a virtual register, go with the earlier decisions and use the physical
// register.
@ -2271,9 +2267,6 @@ MCRegister RAGreedy::selectOrSplitImpl(const LiveInterval &VirtReg,
// copy-related live-ranges.
if (Hint && Hint != PhysReg)
SetOfBrokenHints.insert(&VirtReg);
// If VirtReg eviction someone, the eviction info for it as an evictee is
// no longer relevant.
LastEvicted.clearEvicteeInfo(VirtReg.reg());
return PhysReg;
}
@ -2293,11 +2286,8 @@ MCRegister RAGreedy::selectOrSplitImpl(const LiveInterval &VirtReg,
// Try splitting VirtReg or interferences.
unsigned NewVRegSizeBefore = NewVRegs.size();
Register PhysReg = trySplit(VirtReg, Order, NewVRegs, FixedRegisters);
if (PhysReg || (NewVRegs.size() - NewVRegSizeBefore)) {
// If VirtReg got split, the eviction info is no longer relevant.
LastEvicted.clearEvicteeInfo(VirtReg.reg());
if (PhysReg || (NewVRegs.size() - NewVRegSizeBefore))
return PhysReg;
}
}
// If we couldn't allocate a register from spilling, there is probably some
@ -2545,7 +2535,6 @@ bool RAGreedy::runOnMachineFunction(MachineFunction &mf) {
IntfCache.init(MF, Matrix->getLiveUnions(), Indexes, LIS, TRI);
GlobalCand.resize(32); // This will grow as needed.
SetOfBrokenHints.clear();
LastEvicted.clear();
allocatePhysRegs();
tryHintsRecoloring();

51
llvm/lib/CodeGen/RegAllocGreedy.h
View File

@ -203,57 +203,6 @@ private:
static const char *const StageName[];
#endif
/// EvictionTrack - Keeps track of past evictions in order to optimize region
/// split decision.
class EvictionTrack {
public:
using EvictorInfo =
std::pair<Register /* evictor */, MCRegister /* physreg */>;
using EvicteeInfo = llvm::DenseMap<Register /* evictee */, EvictorInfo>;
private:
/// Each Vreg that has been evicted in the last stage of selectOrSplit will
/// be mapped to the evictor Vreg and the PhysReg it was evicted from.
EvicteeInfo Evictees;
public:
/// Clear all eviction information.
void clear() { Evictees.clear(); }
/// Clear eviction information for the given evictee Vreg.
/// E.g. when Vreg get's a new allocation, the old eviction info is no
/// longer relevant.
/// \param Evictee The evictee Vreg for whom we want to clear collected
/// eviction info.
void clearEvicteeInfo(Register Evictee) { Evictees.erase(Evictee); }
/// Track new eviction.
/// The Evictor vreg has evicted the Evictee vreg from Physreg.
/// \param PhysReg The physical register Evictee was evicted from.
/// \param Evictor The evictor Vreg that evicted Evictee.
/// \param Evictee The evictee Vreg.
void addEviction(MCRegister PhysReg, Register Evictor, Register Evictee) {
Evictees[Evictee].first = Evictor;
Evictees[Evictee].second = PhysReg;
}
/// Return the Evictor Vreg which evicted Evictee Vreg from PhysReg.
/// \param Evictee The evictee vreg.
/// \return The Evictor vreg which evicted Evictee vreg from PhysReg. 0 if
/// nobody has evicted Evictee from PhysReg.
EvictorInfo getEvictor(Register Evictee) {
if (Evictees.count(Evictee)) {
return Evictees[Evictee];
}
return EvictorInfo(0, 0);
}
};
// Keeps track of past evictions in order to optimize region split decision.
EvictionTrack LastEvicted;
// splitting state.
std::unique_ptr<SplitAnalysis> SA;
std::unique_ptr<SplitEditor> SE;