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-rw-r--r--include/llvm/Target/TargetSubtarget.h8
-rw-r--r--lib/CodeGen/AggressiveAntiDepBreaker.cpp120
-rw-r--r--lib/CodeGen/AggressiveAntiDepBreaker.h15
-rw-r--r--lib/CodeGen/PostRASchedulerList.cpp6
-rw-r--r--lib/Target/ARM/ARMSubtarget.cpp6
-rw-r--r--lib/Target/ARM/ARMSubtarget.h2
-rw-r--r--lib/Target/TargetSubtarget.cpp4
-rw-r--r--lib/Target/X86/X86Subtarget.cpp4
-rw-r--r--lib/Target/X86/X86Subtarget.h2
9 files changed, 123 insertions, 44 deletions
diff --git a/include/llvm/Target/TargetSubtarget.h b/include/llvm/Target/TargetSubtarget.h
index f16c9e4ae6..22b09bac07 100644
--- a/include/llvm/Target/TargetSubtarget.h
+++ b/include/llvm/Target/TargetSubtarget.h
@@ -38,7 +38,7 @@ public:
// AntiDepBreakMode - Type of anti-dependence breaking that should
// be performed before post-RA scheduling.
typedef enum { ANTIDEP_NONE, ANTIDEP_CRITICAL, ANTIDEP_ALL } AntiDepBreakMode;
- typedef SmallVectorImpl<TargetRegisterClass*> ExcludedRCVector;
+ typedef SmallVectorImpl<TargetRegisterClass*> RegClassVector;
virtual ~TargetSubtarget();
@@ -50,10 +50,12 @@ public:
// enablePostRAScheduler - If the target can benefit from post-regalloc
// scheduling and the specified optimization level meets the requirement
- // return true to enable post-register-allocation scheduling.
+ // return true to enable post-register-allocation scheduling. In
+ // CriticalPathRCs return any register classes that should only be broken
+ // if on the critical path.
virtual bool enablePostRAScheduler(CodeGenOpt::Level OptLevel,
AntiDepBreakMode& Mode,
- ExcludedRCVector& ExcludedRCs) const;
+ RegClassVector& CriticalPathRCs) const;
// adjustSchedDependency - Perform target specific adjustments to
// the latency of a schedule dependency.
virtual void adjustSchedDependency(SUnit *def, SUnit *use,
diff --git a/lib/CodeGen/AggressiveAntiDepBreaker.cpp b/lib/CodeGen/AggressiveAntiDepBreaker.cpp
index b8cea27e51..c37c793b56 100644
--- a/lib/CodeGen/AggressiveAntiDepBreaker.cpp
+++ b/lib/CodeGen/AggressiveAntiDepBreaker.cpp
@@ -54,10 +54,13 @@ unsigned AggressiveAntiDepState::GetGroup(unsigned Reg)
return Node;
}
-void AggressiveAntiDepState::GetGroupRegs(unsigned Group, std::vector<unsigned> &Regs)
+void AggressiveAntiDepState::GetGroupRegs(
+ unsigned Group,
+ std::vector<unsigned> &Regs,
+ std::multimap<unsigned, AggressiveAntiDepState::RegisterReference> *RegRefs)
{
for (unsigned Reg = 0; Reg != TargetRegisterInfo::FirstVirtualRegister; ++Reg) {
- if (GetGroup(Reg) == Group)
+ if ((GetGroup(Reg) == Group) && (RegRefs->count(Reg) > 0))
Regs.push_back(Reg);
}
}
@@ -100,23 +103,27 @@ bool AggressiveAntiDepState::IsLive(unsigned Reg)
AggressiveAntiDepBreaker::
AggressiveAntiDepBreaker(MachineFunction& MFi,
- TargetSubtarget::ExcludedRCVector& ExcludedRCs) :
+ TargetSubtarget::RegClassVector& CriticalPathRCs) :
AntiDepBreaker(), MF(MFi),
MRI(MF.getRegInfo()),
TRI(MF.getTarget().getRegisterInfo()),
AllocatableSet(TRI->getAllocatableSet(MF)),
State(NULL), SavedState(NULL) {
- /* Remove all registers from excluded RCs from the allocatable
- register set. */
- for (unsigned i = 0, e = ExcludedRCs.size(); i < e; ++i) {
- BitVector NotRenameable = TRI->getAllocatableSet(MF, ExcludedRCs[i]).flip();
- AllocatableSet &= NotRenameable;
- }
-
- DEBUG(errs() << "AntiDep Renameable Registers:");
- DEBUG(for (int r = AllocatableSet.find_first(); r != -1;
- r = AllocatableSet.find_next(r))
+ /* Collect a bitset of all registers that are only broken if they
+ are on the critical path. */
+ for (unsigned i = 0, e = CriticalPathRCs.size(); i < e; ++i) {
+ BitVector CPSet = TRI->getAllocatableSet(MF, CriticalPathRCs[i]);
+ if (CriticalPathSet.none())
+ CriticalPathSet = CPSet;
+ else
+ CriticalPathSet |= CPSet;
+ }
+
+ DEBUG(errs() << "AntiDep Critical-Path Registers:");
+ DEBUG(for (int r = CriticalPathSet.find_first(); r != -1;
+ r = CriticalPathSet.find_next(r))
errs() << " " << TRI->getName(r));
+ DEBUG(errs() << '\n');
}
AggressiveAntiDepBreaker::~AggressiveAntiDepBreaker() {
@@ -276,9 +283,11 @@ void AggressiveAntiDepBreaker::GetPassthruRegs(MachineInstr *MI,
}
}
-/// AntiDepPathStep - Return SUnit that SU has an anti-dependence on.
-static void AntiDepPathStep(SUnit *SU, AntiDepBreaker::AntiDepRegVector& Regs,
- std::vector<SDep*>& Edges) {
+/// AntiDepEdges - Return in Edges the anti- and output-
+/// dependencies on Regs in SU that we want to consider for breaking.
+static void AntiDepEdges(SUnit *SU,
+ const AntiDepBreaker::AntiDepRegVector& Regs,
+ std::vector<SDep*>& Edges) {
AntiDepBreaker::AntiDepRegSet RegSet;
for (unsigned i = 0, e = Regs.size(); i < e; ++i)
RegSet.insert(Regs[i]);
@@ -297,6 +306,31 @@ static void AntiDepPathStep(SUnit *SU, AntiDepBreaker::AntiDepRegVector& Regs,
assert(RegSet.empty() && "Expected all antidep registers to be found");
}
+/// CriticalPathStep - Return the next SUnit after SU on the bottom-up
+/// critical path.
+static SUnit *CriticalPathStep(SUnit *SU) {
+ SDep *Next = 0;
+ unsigned NextDepth = 0;
+ // Find the predecessor edge with the greatest depth.
+ if (SU != 0) {
+ for (SUnit::pred_iterator P = SU->Preds.begin(), PE = SU->Preds.end();
+ P != PE; ++P) {
+ SUnit *PredSU = P->getSUnit();
+ unsigned PredLatency = P->getLatency();
+ unsigned PredTotalLatency = PredSU->getDepth() + PredLatency;
+ // In the case of a latency tie, prefer an anti-dependency edge over
+ // other types of edges.
+ if (NextDepth < PredTotalLatency ||
+ (NextDepth == PredTotalLatency && P->getKind() == SDep::Anti)) {
+ NextDepth = PredTotalLatency;
+ Next = &*P;
+ }
+ }
+ }
+
+ return (Next) ? Next->getSUnit() : 0;
+}
+
void AggressiveAntiDepBreaker::HandleLastUse(unsigned Reg, unsigned KillIdx,
const char *tag) {
unsigned *KillIndices = State->GetKillIndices();
@@ -511,11 +545,11 @@ bool AggressiveAntiDepBreaker::FindSuitableFreeRegisters(
std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>&
RegRefs = State->GetRegRefs();
- // Collect all registers in the same group as AntiDepReg. These all
- // need to be renamed together if we are to break the
- // anti-dependence.
+ // Collect all referenced registers in the same group as
+ // AntiDepReg. These all need to be renamed together if we are to
+ // break the anti-dependence.
std::vector<unsigned> Regs;
- State->GetGroupRegs(AntiDepGroupIndex, Regs);
+ State->GetGroupRegs(AntiDepGroupIndex, Regs, &RegRefs);
assert(Regs.size() > 0 && "Empty register group!");
if (Regs.size() == 0)
return false;
@@ -556,9 +590,10 @@ bool AggressiveAntiDepBreaker::FindSuitableFreeRegisters(
}
// FIXME: for now just handle single register in group case...
- // FIXME: check only regs that have references...
- if (Regs.size() > 1)
+ if (Regs.size() > 1) {
+ DEBUG(errs() << "\tMultiple rename registers in group\n");
return false;
+ }
// Check each possible rename register for SuperReg in round-robin
// order. If that register is available, and the corresponding
@@ -666,6 +701,24 @@ unsigned AggressiveAntiDepBreaker::BreakAntiDependencies(
MISUnitMap.insert(std::pair<MachineInstr *, SUnit *>(SU->getInstr(), SU));
}
+ // Track progress along the critical path through the SUnit graph as
+ // we walk the instructions. This is needed for regclasses that only
+ // break critical-path anti-dependencies.
+ SUnit *CriticalPathSU = 0;
+ MachineInstr *CriticalPathMI = 0;
+ if (CriticalPathSet.any()) {
+ for (unsigned i = 0, e = SUnits.size(); i != e; ++i) {
+ SUnit *SU = &SUnits[i];
+ if (!CriticalPathSU ||
+ ((SU->getDepth() + SU->Latency) >
+ (CriticalPathSU->getDepth() + CriticalPathSU->Latency))) {
+ CriticalPathSU = SU;
+ }
+ }
+
+ CriticalPathMI = CriticalPathSU->getInstr();
+ }
+
// Even if there are no anti-dependencies we still need to go
// through the instructions to update Def, Kills, etc.
#ifndef NDEBUG
@@ -700,14 +753,26 @@ unsigned AggressiveAntiDepBreaker::BreakAntiDependencies(
// Process the defs in MI...
PrescanInstruction(MI, Count, PassthruRegs);
-
+
+ // The the dependence edges that represent anti- and output-
+ // dependencies that are candidates for breaking.
std::vector<SDep*> Edges;
SUnit *PathSU = MISUnitMap[MI];
AntiDepBreaker::CandidateMap::iterator
citer = Candidates.find(PathSU);
if (citer != Candidates.end())
- AntiDepPathStep(PathSU, citer->second, Edges);
-
+ AntiDepEdges(PathSU, citer->second, Edges);
+
+ // If MI is not on the critical path, then we don't rename
+ // registers in the CriticalPathSet.
+ BitVector *ExcludeRegs = NULL;
+ if (MI == CriticalPathMI) {
+ CriticalPathSU = CriticalPathStep(CriticalPathSU);
+ CriticalPathMI = (CriticalPathSU) ? CriticalPathSU->getInstr() : 0;
+ } else {
+ ExcludeRegs = &CriticalPathSet;
+ }
+
// Ignore KILL instructions (they form a group in ScanInstruction
// but don't cause any anti-dependence breaking themselves)
if (MI->getOpcode() != TargetInstrInfo::KILL) {
@@ -727,6 +792,11 @@ unsigned AggressiveAntiDepBreaker::BreakAntiDependencies(
// Don't break anti-dependencies on non-allocatable registers.
DEBUG(errs() << " (non-allocatable)\n");
continue;
+ } else if ((ExcludeRegs != NULL) && ExcludeRegs->test(AntiDepReg)) {
+ // Don't break anti-dependencies for critical path registers
+ // if not on the critical path
+ DEBUG(errs() << " (not critical-path)\n");
+ continue;
} else if (PassthruRegs.count(AntiDepReg) != 0) {
// If the anti-dep register liveness "passes-thru", then
// don't try to change it. It will be changed along with
diff --git a/lib/CodeGen/AggressiveAntiDepBreaker.h b/lib/CodeGen/AggressiveAntiDepBreaker.h
index fb5b869fcb..e5c9a7bb3a 100644
--- a/lib/CodeGen/AggressiveAntiDepBreaker.h
+++ b/lib/CodeGen/AggressiveAntiDepBreaker.h
@@ -86,8 +86,11 @@ namespace llvm {
unsigned GetGroup(unsigned Reg);
// GetGroupRegs - Return a vector of the registers belonging to a
- // group.
- void GetGroupRegs(unsigned Group, std::vector<unsigned> &Regs);
+ // group. If RegRefs is non-NULL then only included referenced registers.
+ void GetGroupRegs(
+ unsigned Group,
+ std::vector<unsigned> &Regs,
+ std::multimap<unsigned, AggressiveAntiDepState::RegisterReference> *RegRefs);
// UnionGroups - Union Reg1's and Reg2's groups to form a new
// group. Return the index of the GroupNode representing the
@@ -113,7 +116,11 @@ namespace llvm {
/// AllocatableSet - The set of allocatable registers.
/// We'll be ignoring anti-dependencies on non-allocatable registers,
/// because they may not be safe to break.
- BitVector AllocatableSet;
+ const BitVector AllocatableSet;
+
+ /// CriticalPathSet - The set of registers that should only be
+ /// renamed if they are on the critical path.
+ BitVector CriticalPathSet;
/// State - The state used to identify and rename anti-dependence
/// registers.
@@ -126,7 +133,7 @@ namespace llvm {
public:
AggressiveAntiDepBreaker(MachineFunction& MFi,
- TargetSubtarget::ExcludedRCVector& ExcludedRCs);
+ TargetSubtarget::RegClassVector& CriticalPathRCs);
~AggressiveAntiDepBreaker();
/// GetMaxTrials - As anti-dependencies are broken, additional
diff --git a/lib/CodeGen/PostRASchedulerList.cpp b/lib/CodeGen/PostRASchedulerList.cpp
index a29f349b0b..5f1f1f3580 100644
--- a/lib/CodeGen/PostRASchedulerList.cpp
+++ b/lib/CodeGen/PostRASchedulerList.cpp
@@ -216,14 +216,14 @@ bool PostRAScheduler::runOnMachineFunction(MachineFunction &Fn) {
// Check for explicit enable/disable of post-ra scheduling.
TargetSubtarget::AntiDepBreakMode AntiDepMode = TargetSubtarget::ANTIDEP_NONE;
- SmallVector<TargetRegisterClass*, 4> ExcludedRCs;
+ SmallVector<TargetRegisterClass*, 4> CriticalPathRCs;
if (EnablePostRAScheduler.getPosition() > 0) {
if (!EnablePostRAScheduler)
return false;
} else {
// Check that post-RA scheduling is enabled for this target.
const TargetSubtarget &ST = Fn.getTarget().getSubtarget<TargetSubtarget>();
- if (!ST.enablePostRAScheduler(OptLevel, AntiDepMode, ExcludedRCs))
+ if (!ST.enablePostRAScheduler(OptLevel, AntiDepMode, CriticalPathRCs))
return false;
}
@@ -244,7 +244,7 @@ bool PostRAScheduler::runOnMachineFunction(MachineFunction &Fn) {
(ScheduleHazardRecognizer *)new SimpleHazardRecognizer();
AntiDepBreaker *ADB =
((AntiDepMode == TargetSubtarget::ANTIDEP_ALL) ?
- (AntiDepBreaker *)new AggressiveAntiDepBreaker(Fn, ExcludedRCs) :
+ (AntiDepBreaker *)new AggressiveAntiDepBreaker(Fn, CriticalPathRCs) :
((AntiDepMode == TargetSubtarget::ANTIDEP_CRITICAL) ?
(AntiDepBreaker *)new CriticalAntiDepBreaker(Fn) : NULL));
diff --git a/lib/Target/ARM/ARMSubtarget.cpp b/lib/Target/ARM/ARMSubtarget.cpp
index dc813289e7..87b78a9ee5 100644
--- a/lib/Target/ARM/ARMSubtarget.cpp
+++ b/lib/Target/ARM/ARMSubtarget.cpp
@@ -164,9 +164,9 @@ ARMSubtarget::GVIsIndirectSymbol(GlobalValue *GV, Reloc::Model RelocM) const {
bool ARMSubtarget::enablePostRAScheduler(
CodeGenOpt::Level OptLevel,
TargetSubtarget::AntiDepBreakMode& Mode,
- ExcludedRCVector& ExcludedRCs) const {
+ RegClassVector& CriticalPathRCs) const {
Mode = TargetSubtarget::ANTIDEP_CRITICAL;
- ExcludedRCs.clear();
- ExcludedRCs.push_back(&ARM::GPRRegClass);
+ CriticalPathRCs.clear();
+ CriticalPathRCs.push_back(&ARM::GPRRegClass);
return PostRAScheduler && OptLevel >= CodeGenOpt::Default;
}
diff --git a/lib/Target/ARM/ARMSubtarget.h b/lib/Target/ARM/ARMSubtarget.h
index fd66693675..a95c8a5ccf 100644
--- a/lib/Target/ARM/ARMSubtarget.h
+++ b/lib/Target/ARM/ARMSubtarget.h
@@ -130,7 +130,7 @@ protected:
/// enablePostRAScheduler - True at 'More' optimization.
bool enablePostRAScheduler(CodeGenOpt::Level OptLevel,
TargetSubtarget::AntiDepBreakMode& Mode,
- ExcludedRCVector& ExcludedRCs) const;
+ RegClassVector& CriticalPathRCs) const;
/// getInstrItins - Return the instruction itineraies based on subtarget
/// selection.
diff --git a/lib/Target/TargetSubtarget.cpp b/lib/Target/TargetSubtarget.cpp
index 696c09b52f..edb76f9715 100644
--- a/lib/Target/TargetSubtarget.cpp
+++ b/lib/Target/TargetSubtarget.cpp
@@ -25,9 +25,9 @@ TargetSubtarget::~TargetSubtarget() {}
bool TargetSubtarget::enablePostRAScheduler(
CodeGenOpt::Level OptLevel,
AntiDepBreakMode& Mode,
- ExcludedRCVector& ExcludedRCs) const {
+ RegClassVector& CriticalPathRCs) const {
Mode = ANTIDEP_NONE;
- ExcludedRCs.clear();
+ CriticalPathRCs.clear();
return false;
}
diff --git a/lib/Target/X86/X86Subtarget.cpp b/lib/Target/X86/X86Subtarget.cpp
index a7233b52b2..893640561c 100644
--- a/lib/Target/X86/X86Subtarget.cpp
+++ b/lib/Target/X86/X86Subtarget.cpp
@@ -460,8 +460,8 @@ X86Subtarget::X86Subtarget(const std::string &TT, const std::string &FS,
bool X86Subtarget::enablePostRAScheduler(
CodeGenOpt::Level OptLevel,
TargetSubtarget::AntiDepBreakMode& Mode,
- ExcludedRCVector& ExcludedRCs) const {
+ RegClassVector& CriticalPathRCs) const {
Mode = TargetSubtarget::ANTIDEP_CRITICAL;
- ExcludedRCs.clear();
+ CriticalPathRCs.clear();
return OptLevel >= CodeGenOpt::Default;
}
diff --git a/lib/Target/X86/X86Subtarget.h b/lib/Target/X86/X86Subtarget.h
index a0eef0551e..23f2841a8c 100644
--- a/lib/Target/X86/X86Subtarget.h
+++ b/lib/Target/X86/X86Subtarget.h
@@ -220,7 +220,7 @@ public:
/// at 'More' optimization level.
bool enablePostRAScheduler(CodeGenOpt::Level OptLevel,
TargetSubtarget::AntiDepBreakMode& Mode,
- ExcludedRCVector& ExcludedRCs) const;
+ RegClassVector& CriticalPathRCs) const;
};
} // End llvm namespace
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-29 22:20:33 +0000