#include "LiveRangeEdit.h"
#include "VirtRegMap.h"
#include "VirtRegRewriter.h"
+#include "RegisterClassInfo.h"
#include "Spiller.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Function.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/RegAllocRegistry.h"
-#include "llvm/CodeGen/RegisterCoalescer.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
-#include <set>
#include <queue>
#include <memory>
#include <cmath>
cl::desc("Use new spilling heuristic"),
cl::init(false), cl::Hidden);
-static cl::opt<bool>
-PreSplitIntervals("pre-alloc-split",
- cl::desc("Pre-register allocation live interval splitting"),
- cl::init(false), cl::Hidden);
-
static cl::opt<bool>
TrivCoalesceEnds("trivial-coalesce-ends",
cl::desc("Attempt trivial coalescing of interval ends"),
cl::init(false), cl::Hidden);
+static cl::opt<bool>
+AvoidWAWHazard("avoid-waw-hazard",
+ cl::desc("Avoid write-write hazards for some register classes"),
+ cl::init(false), cl::Hidden);
+
static RegisterRegAlloc
linearscanRegAlloc("linearscan", "linear scan register allocator",
createLinearScanRegisterAllocator);
initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry());
initializeLiveIntervalsPass(*PassRegistry::getPassRegistry());
initializeStrongPHIEliminationPass(*PassRegistry::getPassRegistry());
- initializeRegisterCoalescerAnalysisGroup(
+ initializeRegisterCoalescerPass(
*PassRegistry::getPassRegistry());
initializeCalculateSpillWeightsPass(*PassRegistry::getPassRegistry());
- initializePreAllocSplittingPass(*PassRegistry::getPassRegistry());
initializeLiveStacksPass(*PassRegistry::getPassRegistry());
initializeMachineDominatorTreePass(*PassRegistry::getPassRegistry());
initializeMachineLoopInfoPass(*PassRegistry::getPassRegistry());
if (NumRecentlyUsedRegs > 0)
RecentRegs.resize(NumRecentlyUsedRegs, 0);
RecentNext = RecentRegs.begin();
+ avoidWAW_ = 0;
}
typedef std::pair<LiveInterval*, LiveInterval::iterator> IntervalPtr;
BitVector reservedRegs_;
LiveIntervals* li_;
MachineLoopInfo *loopInfo;
+ RegisterClassInfo RegClassInfo;
/// handled_ - Intervals are added to the handled_ set in the order of their
/// start value. This is uses for backtracking.
SmallVector<unsigned, 4> RecentRegs;
SmallVector<unsigned, 4>::iterator RecentNext;
+ // Last write-after-write register written.
+ unsigned avoidWAW_;
+
// Record that we just picked this register.
void recordRecentlyUsed(unsigned reg) {
assert(reg != 0 && "Recently used register is NOREG!");
AU.addRequiredID(StrongPHIEliminationID);
// Make sure PassManager knows which analyses to make available
// to coalescing and which analyses coalescing invalidates.
- AU.addRequiredTransitive<RegisterCoalescer>();
+ AU.addRequiredTransitiveID(RegisterCoalescerPassID);
AU.addRequired<CalculateSpillWeights>();
- if (PreSplitIntervals)
- AU.addRequiredID(PreAllocSplittingID);
AU.addRequiredID(LiveStacksID);
AU.addPreservedID(LiveStacksID);
AU.addRequired<MachineLoopInfo>();
// Determine if we skip this register due to its being recently used.
bool isRecentlyUsed(unsigned reg) const {
- return std::find(RecentRegs.begin(), RecentRegs.end(), reg) !=
- RecentRegs.end();
+ return reg == avoidWAW_ ||
+ std::find(RecentRegs.begin(), RecentRegs.end(), reg) != RecentRegs.end();
}
private:
/// getFirstNonReservedPhysReg - return the first non-reserved physical
/// register in the register class.
unsigned getFirstNonReservedPhysReg(const TargetRegisterClass *RC) {
- TargetRegisterClass::iterator aoe = RC->allocation_order_end(*mf_);
- TargetRegisterClass::iterator i = RC->allocation_order_begin(*mf_);
- while (i != aoe && reservedRegs_.test(*i))
- ++i;
- assert(i != aoe && "All registers reserved?!");
- return *i;
- }
+ ArrayRef<unsigned> O = RegClassInfo.getOrder(RC);
+ assert(!O.empty() && "All registers reserved?!");
+ return O.front();
+ }
void ComputeRelatedRegClasses();
INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
INITIALIZE_PASS_DEPENDENCY(StrongPHIElimination)
INITIALIZE_PASS_DEPENDENCY(CalculateSpillWeights)
-INITIALIZE_PASS_DEPENDENCY(PreAllocSplitting)
INITIALIZE_PASS_DEPENDENCY(LiveStacks)
INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
INITIALIZE_PASS_DEPENDENCY(VirtRegMap)
-INITIALIZE_AG_DEPENDENCY(RegisterCoalescer)
+INITIALIZE_PASS_DEPENDENCY(RegisterCoalescer)
INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
INITIALIZE_PASS_END(RALinScan, "linearscan-regalloc",
"Linear Scan Register Allocator", false, false)
reservedRegs_ = tri_->getReservedRegs(fn);
li_ = &getAnalysis<LiveIntervals>();
loopInfo = &getAnalysis<MachineLoopInfo>();
+ RegClassInfo.runOnMachineFunction(fn);
// We don't run the coalescer here because we have no reason to
// interact with it. If the coalescer requires interaction, it
active_.push_back(std::make_pair(cur, cur->begin()));
handled_.push_back(cur);
+ // Remember physReg for avoiding a write-after-write hazard in the next
+ // instruction.
+ if (AvoidWAWHazard &&
+ tri_->avoidWriteAfterWrite(mri_->getRegClass(cur->reg)))
+ avoidWAW_ = physReg;
+
// "Upgrade" the physical register since it has been allocated.
UpgradeRegister(physReg);
if (LiveInterval *NextReloadLI = hasNextReloadInterval(cur)) {
bool Found = false;
std::vector<std::pair<unsigned,float> > RegsWeights;
+ ArrayRef<unsigned> Order = RegClassInfo.getOrder(RC);
if (!minReg || SpillWeights[minReg] == HUGE_VALF)
- for (TargetRegisterClass::iterator i = RC->allocation_order_begin(*mf_),
- e = RC->allocation_order_end(*mf_); i != e; ++i) {
- unsigned reg = *i;
+ for (unsigned i = 0; i != Order.size(); ++i) {
+ unsigned reg = Order[i];
float regWeight = SpillWeights[reg];
- // Don't even consider reserved regs.
- if (reservedRegs_.test(reg))
- continue;
// Skip recently allocated registers and reserved registers.
if (minWeight > regWeight && !isRecentlyUsed(reg))
Found = true;
// If we didn't find a register that is spillable, try aliases?
if (!Found) {
- for (TargetRegisterClass::iterator i = RC->allocation_order_begin(*mf_),
- e = RC->allocation_order_end(*mf_); i != e; ++i) {
- unsigned reg = *i;
- if (reservedRegs_.test(reg))
- continue;
+ for (unsigned i = 0; i != Order.size(); ++i) {
+ unsigned reg = Order[i];
// No need to worry about if the alias register size < regsize of RC.
// We are going to spill all registers that alias it anyway.
for (const unsigned* as = tri_->getAliasSet(reg); *as; ++as)
if (TargetRegisterInfo::isVirtualRegister(physReg) && vrm_->hasPhys(physReg))
physReg = vrm_->getPhys(physReg);
- TargetRegisterClass::iterator I, E;
- tie(I, E) = tri_->getAllocationOrder(RC, Hint.first, physReg, *mf_);
- assert(I != E && "No allocatable register in this register class!");
+ ArrayRef<unsigned> Order;
+ if (Hint.first)
+ Order = tri_->getRawAllocationOrder(RC, Hint.first, physReg, *mf_);
+ else
+ Order = RegClassInfo.getOrder(RC);
+
+ assert(!Order.empty() && "No allocatable register in this register class!");
// Scan for the first available register.
- for (; I != E; ++I) {
- unsigned Reg = *I;
+ for (unsigned i = 0; i != Order.size(); ++i) {
+ unsigned Reg = Order[i];
// Ignore "downgraded" registers.
if (SkipDGRegs && DowngradedRegs.count(Reg))
continue;
if (reservedRegs_.test(Reg))
continue;
// Skip recently allocated registers.
- if (isRegAvail(Reg) && !isRecentlyUsed(Reg)) {
+ if (isRegAvail(Reg) && (!SkipDGRegs || !isRecentlyUsed(Reg))) {
FreeReg = Reg;
if (FreeReg < inactiveCounts.size())
FreeRegInactiveCount = inactiveCounts[FreeReg];
// inactive count. Alkis found that this reduced register pressure very
// slightly on X86 (in rev 1.94 of this file), though this should probably be
// reevaluated now.
- for (; I != E; ++I) {
- unsigned Reg = *I;
+ for (unsigned i = 0; i != Order.size(); ++i) {
+ unsigned Reg = Order[i];
// Ignore "downgraded" registers.
if (SkipDGRegs && DowngradedRegs.count(Reg))
continue;
if (reservedRegs_.test(Reg))
continue;
if (isRegAvail(Reg) && Reg < inactiveCounts.size() &&
- FreeRegInactiveCount < inactiveCounts[Reg] && !isRecentlyUsed(Reg)) {
+ FreeRegInactiveCount < inactiveCounts[Reg] &&
+ (!SkipDGRegs || !isRecentlyUsed(Reg))) {
FreeReg = Reg;
FreeRegInactiveCount = inactiveCounts[Reg];
if (FreeRegInactiveCount == MaxInactiveCount)
return Preference;
}
- if (!DowngradedRegs.empty()) {
- unsigned FreeReg = getFreePhysReg(cur, RC, MaxInactiveCount, inactiveCounts,
- true);
- if (FreeReg)
- return FreeReg;
- }
+ unsigned FreeReg = getFreePhysReg(cur, RC, MaxInactiveCount, inactiveCounts,
+ true);
+ if (FreeReg)
+ return FreeReg;
return getFreePhysReg(cur, RC, MaxInactiveCount, inactiveCounts, false);
}
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