Remove some old experimental code that is no longer needed. Remove additional, speculative scheduling pass as its cost did not translate into significant performance improvement. Minor tweaks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89471 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AggressiveAntiDepBreaker.cpp b/lib/CodeGen/AggressiveAntiDepBreaker.cpp
index 76451bb..f9c2bf0 100644
--- a/lib/CodeGen/AggressiveAntiDepBreaker.cpp
+++ b/lib/CodeGen/AggressiveAntiDepBreaker.cpp
@@ -28,11 +28,6 @@
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
-static cl::opt<int>
-AntiDepTrials("agg-antidep-trials",
- cl::desc("Maximum number of anti-dependency breaking passes"),
- cl::init(1), cl::Hidden);
-
// If DebugDiv > 0 then only break antidep with (ID % DebugDiv) == DebugMod
static cl::opt<int>
DebugDiv("agg-antidep-debugdiv",
@@ -118,7 +113,7 @@
MRI(MF.getRegInfo()),
TRI(MF.getTarget().getRegisterInfo()),
AllocatableSet(TRI->getAllocatableSet(MF)),
- State(NULL), SavedState(NULL) {
+ State(NULL) {
/* 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) {
@@ -138,13 +133,6 @@
AggressiveAntiDepBreaker::~AggressiveAntiDepBreaker() {
delete State;
- delete SavedState;
-}
-
-unsigned AggressiveAntiDepBreaker::GetMaxTrials() {
- if (AntiDepTrials <= 0)
- return 1;
- return AntiDepTrials;
}
void AggressiveAntiDepBreaker::StartBlock(MachineBasicBlock *BB) {
@@ -216,8 +204,6 @@
void AggressiveAntiDepBreaker::FinishBlock() {
delete State;
State = NULL;
- delete SavedState;
- SavedState = NULL;
}
void AggressiveAntiDepBreaker::Observe(MachineInstr *MI, unsigned Count,
@@ -251,10 +237,6 @@
}
}
DEBUG(errs() << '\n');
-
- // We're starting a new schedule region so forget any saved state.
- delete SavedState;
- SavedState = NULL;
}
bool AggressiveAntiDepBreaker::IsImplicitDefUse(MachineInstr *MI,
@@ -293,27 +275,20 @@
}
}
-/// 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]);
-
+/// AntiDepEdges - Return in Edges the anti- and output- dependencies
+/// in SU that we want to consider for breaking.
+static void AntiDepEdges(SUnit *SU, std::vector<SDep*>& Edges) {
+ SmallSet<unsigned, 4> RegSet;
for (SUnit::pred_iterator P = SU->Preds.begin(), PE = SU->Preds.end();
P != PE; ++P) {
if ((P->getKind() == SDep::Anti) || (P->getKind() == SDep::Output)) {
unsigned Reg = P->getReg();
- if (RegSet.count(Reg) != 0) {
+ if (RegSet.count(Reg) == 0) {
Edges.push_back(&*P);
- RegSet.erase(Reg);
+ RegSet.insert(Reg);
}
}
}
-
- assert(RegSet.empty() && "Expected all antidep registers to be found");
}
/// CriticalPathStep - Return the next SUnit after SU on the bottom-up
@@ -698,7 +673,6 @@
///
unsigned AggressiveAntiDepBreaker::BreakAntiDependencies(
std::vector<SUnit>& SUnits,
- CandidateMap& Candidates,
MachineBasicBlock::iterator& Begin,
MachineBasicBlock::iterator& End,
unsigned InsertPosIndex) {
@@ -711,16 +685,6 @@
// so just duck out immediately if the block is empty.
if (SUnits.empty()) return 0;
- // Manage saved state to enable multiple passes...
- if (AntiDepTrials > 1) {
- if (SavedState == NULL) {
- SavedState = new AggressiveAntiDepState(*State);
- } else {
- delete State;
- State = new AggressiveAntiDepState(*SavedState);
- }
- }
-
// For each regclass the next register to use for renaming.
RenameOrderType RenameOrder;
@@ -749,21 +713,14 @@
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
- if (Candidates.empty()) {
- DEBUG(errs() << "\n===== No anti-dependency candidates\n");
- } else {
- DEBUG(errs() << "\n===== Attempting to break " << Candidates.size() <<
- " anti-dependencies\n");
- DEBUG(errs() << "Available regs:");
- for (unsigned Reg = 0; Reg < TRI->getNumRegs(); ++Reg) {
- if (!State->IsLive(Reg))
- DEBUG(errs() << " " << TRI->getName(Reg));
- }
- DEBUG(errs() << '\n');
+ DEBUG(errs() << "\n===== Aggressive anti-dependency breaking\n");
+ DEBUG(errs() << "Available regs:");
+ for (unsigned Reg = 0; Reg < TRI->getNumRegs(); ++Reg) {
+ if (!State->IsLive(Reg))
+ DEBUG(errs() << " " << TRI->getName(Reg));
}
+ DEBUG(errs() << '\n');
#endif
// Attempt to break anti-dependence edges. Walk the instructions
@@ -784,14 +741,11 @@
// Process the defs in MI...
PrescanInstruction(MI, Count, PassthruRegs);
- // The the dependence edges that represent anti- and output-
+ // 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())
- AntiDepEdges(PathSU, citer->second, Edges);
+ AntiDepEdges(PathSU, Edges);
// If MI is not on the critical path, then we don't rename
// registers in the CriticalPathSet.
@@ -847,12 +801,32 @@
// anti-dependency since those edges would prevent such
// units from being scheduled past each other
// regardless.
+ //
+ // Also, if there are dependencies on other SUnits with the
+ // same register as the anti-dependency, don't attempt to
+ // break it.
for (SUnit::pred_iterator P = PathSU->Preds.begin(),
PE = PathSU->Preds.end(); P != PE; ++P) {
- if ((P->getSUnit() == NextSU) && (P->getKind() != SDep::Anti)) {
+ if (P->getSUnit() == NextSU ?
+ (P->getKind() != SDep::Anti || P->getReg() != AntiDepReg) :
+ (P->getKind() == SDep::Data && P->getReg() == AntiDepReg)) {
+ AntiDepReg = 0;
+ break;
+ }
+ }
+ for (SUnit::pred_iterator P = PathSU->Preds.begin(),
+ PE = PathSU->Preds.end(); P != PE; ++P) {
+ if ((P->getSUnit() == NextSU) && (P->getKind() != SDep::Anti) &&
+ (P->getKind() != SDep::Output)) {
DEBUG(errs() << " (real dependency)\n");
AntiDepReg = 0;
break;
+ } else if ((P->getSUnit() != NextSU) &&
+ (P->getKind() == SDep::Data) &&
+ (P->getReg() == AntiDepReg)) {
+ DEBUG(errs() << " (other dependency)\n");
+ AntiDepReg = 0;
+ break;
}
}