//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "regalloc"
+#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "PhysRegTracker.h"
#include "VirtRegMap.h"
#include <cmath>
using namespace llvm;
-namespace {
-
- static Statistic NumIters
- ("regalloc", "Number of iterations performed");
- static Statistic NumBacktracks
- ("regalloc", "Number of times we had to backtrack");
+STATISTIC(NumIters , "Number of iterations performed");
+STATISTIC(NumBacktracks, "Number of times we had to backtrack");
- static RegisterRegAlloc
- linearscanRegAlloc("linearscan", " linear scan register allocator",
- createLinearScanRegisterAllocator);
+static RegisterRegAlloc
+linearscanRegAlloc("linearscan", " linear scan register allocator",
+ createLinearScanRegisterAllocator);
+namespace {
static unsigned numIterations = 0;
static unsigned numIntervals = 0;
const TargetMachine* tm_;
const MRegisterInfo* mri_;
LiveIntervals* li_;
- bool *PhysRegsUsed;
/// handled_ - Intervals are added to the handled_ set in the order of their
/// start value. This is uses for backtracking.
if (RelatedRegClasses.empty())
ComputeRelatedRegClasses();
- PhysRegsUsed = new bool[mri_->getNumRegs()];
- std::fill(PhysRegsUsed, PhysRegsUsed+mri_->getNumRegs(), false);
- fn.setUsedPhysRegs(PhysRegsUsed);
-
if (!prt_.get()) prt_.reset(new PhysRegTracker(*mri_));
vrm_.reset(new VirtRegMap(*mf_));
if (!spiller_.get()) spiller_.reset(createSpiller());
for (LiveIntervals::iterator i = li_->begin(), e = li_->end(); i != e; ++i) {
if (MRegisterInfo::isPhysicalRegister(i->second.reg)) {
- PhysRegsUsed[i->second.reg] = true;
+ mf_->setPhysRegUsed(i->second.reg);
fixed_.push_back(std::make_pair(&i->second, i->second.begin()));
} else
unhandled_.push(&i->second);
i = IntervalPtrs::reverse_iterator(inactive_.erase(i.base()-1));
}
+ // A brute force way of adding live-ins to every BB.
+ MachineFunction::iterator MBB = mf_->begin();
+ ++MBB; // Skip entry MBB.
+ for (MachineFunction::iterator E = mf_->end(); MBB != E; ++MBB) {
+ unsigned StartIdx = li_->getMBBStartIdx(MBB->getNumber());
+ for (IntervalPtrs::iterator i = fixed_.begin(), e = fixed_.end();
+ i != e; ++i)
+ if (i->first->liveAt(StartIdx))
+ MBB->addLiveIn(i->first->reg);
+
+ for (unsigned i = 0, e = handled_.size(); i != e; ++i) {
+ LiveInterval *HI = handled_[i];
+ unsigned Reg = HI->reg;
+ if (!vrm_->hasStackSlot(Reg) && HI->liveAt(StartIdx)) {
+ assert(MRegisterInfo::isVirtualRegister(Reg));
+ Reg = vrm_->getPhys(Reg);
+ MBB->addLiveIn(Reg);
+ }
+ }
+ }
+
DOUT << *vrm_;
}
// Find a register to spill.
float minWeight = HUGE_VALF;
- unsigned minReg = 0;
- for (TargetRegisterClass::iterator i = RC->allocation_order_begin(*mf_),
- e = RC->allocation_order_end(*mf_); i != e; ++i) {
- unsigned reg = *i;
- if (minWeight > SpillWeights[reg]) {
- minWeight = SpillWeights[reg];
- minReg = reg;
+ unsigned minReg = cur->preference; // Try the preferred register first.
+
+ 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;
+ if (minWeight > SpillWeights[reg]) {
+ minWeight = SpillWeights[reg];
+ minReg = reg;
+ }
}
- }
// If we didn't find a register that is spillable, try aliases?
if (!minReg) {
// linearscan.
if (cur->weight != HUGE_VALF && cur->weight <= minWeight) {
DOUT << "\t\t\tspilling(c): " << *cur << '\n';
- int slot = vrm_->assignVirt2StackSlot(cur->reg);
+ // if the current interval is re-materializable, remember so and don't
+ // assign it a spill slot.
+ if (cur->remat)
+ vrm_->setVirtIsReMaterialized(cur->reg, cur->remat);
+ int slot = cur->remat ? vrm_->assignVirtReMatId(cur->reg)
+ : vrm_->assignVirt2StackSlot(cur->reg);
std::vector<LiveInterval*> added =
li_->addIntervalsForSpills(*cur, *vrm_, slot);
if (added.empty())
std::vector<LiveInterval*> added;
assert(MRegisterInfo::isPhysicalRegister(minReg) &&
"did not choose a register to spill?");
- std::vector<bool> toSpill(mri_->getNumRegs(), false);
+ BitVector toSpill(mri_->getNumRegs());
// We are going to spill minReg and all its aliases.
toSpill[minReg] = true;
cur->overlapsFrom(*i->first, i->second)) {
DOUT << "\t\t\tspilling(a): " << *i->first << '\n';
earliestStart = std::min(earliestStart, i->first->beginNumber());
- int slot = vrm_->assignVirt2StackSlot(i->first->reg);
+ if (i->first->remat)
+ vrm_->setVirtIsReMaterialized(reg, i->first->remat);
+ int slot = i->first->remat ? vrm_->assignVirtReMatId(reg)
+ : vrm_->assignVirt2StackSlot(reg);
std::vector<LiveInterval*> newIs =
li_->addIntervalsForSpills(*i->first, *vrm_, slot);
std::copy(newIs.begin(), newIs.end(), std::back_inserter(added));
cur->overlapsFrom(*i->first, i->second-1)) {
DOUT << "\t\t\tspilling(i): " << *i->first << '\n';
earliestStart = std::min(earliestStart, i->first->beginNumber());
- int slot = vrm_->assignVirt2StackSlot(reg);
+ if (i->first->remat)
+ vrm_->setVirtIsReMaterialized(reg, i->first->remat);
+ int slot = i->first->remat ? vrm_->assignVirtReMatId(reg)
+ : vrm_->assignVirt2StackSlot(reg);
std::vector<LiveInterval*> newIs =
li_->addIntervalsForSpills(*i->first, *vrm_, slot);
std::copy(newIs.begin(), newIs.end(), std::back_inserter(added));
}
}
- const TargetRegisterClass* rc = mf_->getSSARegMap()->getRegClass(cur->reg);
-
unsigned FreeReg = 0;
unsigned FreeRegInactiveCount = 0;
-
+
+ // If copy coalescer has assigned a "preferred" register, check if it's
+ // available first.
+ if (cur->preference)
+ if (prt_->isRegAvail(cur->preference)) {
+ DOUT << "\t\tassigned the preferred register: "
+ << mri_->getName(cur->preference) << "\n";
+ return cur->preference;
+ } else
+ DOUT << "\t\tunable to assign the preferred register: "
+ << mri_->getName(cur->preference) << "\n";
+
// Scan for the first available register.
- TargetRegisterClass::iterator I = rc->allocation_order_begin(*mf_);
- TargetRegisterClass::iterator E = rc->allocation_order_end(*mf_);
+ TargetRegisterClass::iterator I = RC->allocation_order_begin(*mf_);
+ TargetRegisterClass::iterator E = RC->allocation_order_end(*mf_);
for (; I != E; ++I)
if (prt_->isRegAvail(*I)) {
FreeReg = *I;