ReMatDefs.clear();
}
-bool SimpleRegisterCoalescing::isZeroLengthInterval(LiveInterval *li) const {
+/// Returns true if the given live interval is zero length.
+static bool isZeroLengthInterval(LiveInterval *li, LiveIntervals *li_) {
for (LiveInterval::Ranges::const_iterator
i = li->ranges.begin(), e = li->ranges.end(); i != e; ++i)
if (li_->getPrevIndex(i->end) > i->start)
return true;
}
+void SimpleRegisterCoalescing::CalculateSpillWeights() {
+ SmallSet<unsigned, 4> Processed;
+ for (MachineFunction::iterator mbbi = mf_->begin(), mbbe = mf_->end();
+ mbbi != mbbe; ++mbbi) {
+ MachineBasicBlock* MBB = mbbi;
+ MachineInstrIndex MBBEnd = li_->getMBBEndIdx(MBB);
+ MachineLoop* loop = loopInfo->getLoopFor(MBB);
+ unsigned loopDepth = loop ? loop->getLoopDepth() : 0;
+ bool isExit = loop ? loop->isLoopExit(MBB) : false;
+
+ for (MachineBasicBlock::iterator mii = MBB->begin(), mie = MBB->end();
+ mii != mie; ++mii) {
+ MachineInstr *MI = mii;
+
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ const MachineOperand &mopi = MI->getOperand(i);
+ if (!mopi.isReg() || mopi.getReg() == 0)
+ continue;
+ unsigned Reg = mopi.getReg();
+ if (!TargetRegisterInfo::isVirtualRegister(mopi.getReg()))
+ continue;
+ // Multiple uses of reg by the same instruction. It should not
+ // contribute to spill weight again.
+ if (!Processed.insert(Reg))
+ continue;
+
+ bool HasDef = mopi.isDef();
+ bool HasUse = mopi.isUse();
+ for (unsigned j = i+1; j != e; ++j) {
+ const MachineOperand &mopj = MI->getOperand(j);
+ if (!mopj.isReg() || mopj.getReg() != Reg)
+ continue;
+ HasDef |= mopj.isDef();
+ HasUse |= mopj.isUse();
+ }
+
+ LiveInterval &RegInt = li_->getInterval(Reg);
+ float Weight = li_->getSpillWeight(HasDef, HasUse, loopDepth+1);
+ if (HasDef && isExit) {
+ // Looks like this is a loop count variable update.
+ MachineInstrIndex DefIdx =
+ li_->getDefIndex(li_->getInstructionIndex(MI));
+ const LiveRange *DLR =
+ li_->getInterval(Reg).getLiveRangeContaining(DefIdx);
+ if (DLR->end > MBBEnd)
+ Weight *= 3.0F;
+ }
+ RegInt.weight += Weight;
+ }
+ Processed.clear();
+ }
+ }
+
+ for (LiveIntervals::iterator I = li_->begin(), E = li_->end(); I != E; ++I) {
+ LiveInterval &LI = *I->second;
+ if (TargetRegisterInfo::isVirtualRegister(LI.reg)) {
+ // If the live interval length is essentially zero, i.e. in every live
+ // range the use follows def immediately, it doesn't make sense to spill
+ // it and hope it will be easier to allocate for this li.
+ if (isZeroLengthInterval(&LI, li_)) {
+ LI.weight = HUGE_VALF;
+ continue;
+ }
+
+ bool isLoad = false;
+ SmallVector<LiveInterval*, 4> SpillIs;
+ if (li_->isReMaterializable(LI, SpillIs, isLoad)) {
+ // If all of the definitions of the interval are re-materializable,
+ // it is a preferred candidate for spilling. If non of the defs are
+ // loads, then it's potentially very cheap to re-materialize.
+ // FIXME: this gets much more complicated once we support non-trivial
+ // re-materialization.
+ if (isLoad)
+ LI.weight *= 0.9F;
+ else
+ LI.weight *= 0.5F;
+ }
+
+ // Slightly prefer live interval that has been assigned a preferred reg.
+ std::pair<unsigned, unsigned> Hint = mri_->getRegAllocationHint(LI.reg);
+ if (Hint.first || Hint.second)
+ LI.weight *= 1.01F;
+
+ // Divide the weight of the interval by its size. This encourages
+ // spilling of intervals that are large and have few uses, and
+ // discourages spilling of small intervals with many uses.
+ LI.weight /= li_->getApproximateInstructionCount(LI) * InstrSlots::NUM;
+ }
+ }
+}
+
bool SimpleRegisterCoalescing::runOnMachineFunction(MachineFunction &fn) {
mf_ = &fn;
for (MachineFunction::iterator mbbi = mf_->begin(), mbbe = mf_->end();
mbbi != mbbe; ++mbbi) {
MachineBasicBlock* mbb = mbbi;
- unsigned loopDepth = loopInfo->getLoopDepth(mbb);
-
for (MachineBasicBlock::iterator mii = mbb->begin(), mie = mbb->end();
mii != mie; ) {
MachineInstr *MI = mii;
mii = mbbi->erase(mii);
++numPeep;
} else {
- SmallSet<unsigned, 4> UniqueUses;
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- const MachineOperand &mop = MI->getOperand(i);
- if (mop.isReg() && mop.getReg() &&
- TargetRegisterInfo::isVirtualRegister(mop.getReg())) {
- unsigned reg = mop.getReg();
- // Multiple uses of reg by the same instruction. It should not
- // contribute to spill weight again.
- if (UniqueUses.count(reg) != 0)
- continue;
- LiveInterval &RegInt = li_->getInterval(reg);
- RegInt.weight +=
- li_->getSpillWeight(mop.isDef(), mop.isUse(), loopDepth);
- UniqueUses.insert(reg);
- }
- }
++mii;
}
}
}
- for (LiveIntervals::iterator I = li_->begin(), E = li_->end(); I != E; ++I) {
- LiveInterval &LI = *I->second;
- if (TargetRegisterInfo::isVirtualRegister(LI.reg)) {
- // If the live interval length is essentially zero, i.e. in every live
- // range the use follows def immediately, it doesn't make sense to spill
- // it and hope it will be easier to allocate for this li.
- if (isZeroLengthInterval(&LI))
- LI.weight = HUGE_VALF;
- else {
- bool isLoad = false;
- SmallVector<LiveInterval*, 4> SpillIs;
- if (li_->isReMaterializable(LI, SpillIs, isLoad)) {
- // If all of the definitions of the interval are re-materializable,
- // it is a preferred candidate for spilling. If non of the defs are
- // loads, then it's potentially very cheap to re-materialize.
- // FIXME: this gets much more complicated once we support non-trivial
- // re-materialization.
- if (isLoad)
- LI.weight *= 0.9F;
- else
- LI.weight *= 0.5F;
- }
- }
-
- // Slightly prefer live interval that has been assigned a preferred reg.
- std::pair<unsigned, unsigned> Hint = mri_->getRegAllocationHint(LI.reg);
- if (Hint.first || Hint.second)
- LI.weight *= 1.01F;
-
- // Divide the weight of the interval by its size. This encourages
- // spilling of intervals that are large and have few uses, and
- // discourages spilling of small intervals with many uses.
- LI.weight /= li_->getApproximateInstructionCount(LI) * InstrSlots::NUM;
- }
- }
+ CalculateSpillWeights();
DEBUG(dump());
return true;
--- /dev/null
+; RUN: llc < %s -mtriple=i386-apple-darwin10.0 -relocation-model=pic | FileCheck %s
+
+define void @dot(i16* nocapture %A, i32 %As, i16* nocapture %B, i32 %Bs, i16* nocapture %C, i32 %N) nounwind ssp {
+; CHECK: dot:
+; CHECK: decl %
+; CHECK-NEXT: jne
+entry:
+ %0 = icmp sgt i32 %N, 0 ; <i1> [#uses=1]
+ br i1 %0, label %bb, label %bb2
+
+bb: ; preds = %bb, %entry
+ %i.03 = phi i32 [ 0, %entry ], [ %indvar.next, %bb ] ; <i32> [#uses=3]
+ %sum.04 = phi i32 [ 0, %entry ], [ %10, %bb ] ; <i32> [#uses=1]
+ %1 = mul i32 %i.03, %As ; <i32> [#uses=1]
+ %2 = getelementptr i16* %A, i32 %1 ; <i16*> [#uses=1]
+ %3 = load i16* %2, align 2 ; <i16> [#uses=1]
+ %4 = sext i16 %3 to i32 ; <i32> [#uses=1]
+ %5 = mul i32 %i.03, %Bs ; <i32> [#uses=1]
+ %6 = getelementptr i16* %B, i32 %5 ; <i16*> [#uses=1]
+ %7 = load i16* %6, align 2 ; <i16> [#uses=1]
+ %8 = sext i16 %7 to i32 ; <i32> [#uses=1]
+ %9 = mul i32 %8, %4 ; <i32> [#uses=1]
+ %10 = add i32 %9, %sum.04 ; <i32> [#uses=2]
+ %indvar.next = add i32 %i.03, 1 ; <i32> [#uses=2]
+ %exitcond = icmp eq i32 %indvar.next, %N ; <i1> [#uses=1]
+ br i1 %exitcond, label %bb1.bb2_crit_edge, label %bb
+
+bb1.bb2_crit_edge: ; preds = %bb
+ %phitmp = trunc i32 %10 to i16 ; <i16> [#uses=1]
+ br label %bb2
+
+bb2: ; preds = %entry, %bb1.bb2_crit_edge
+ %sum.0.lcssa = phi i16 [ %phitmp, %bb1.bb2_crit_edge ], [ 0, %entry ] ; <i16> [#uses=1]
+ store i16 %sum.0.lcssa, i16* %C, align 2
+ ret void
+}
projects / oota-llvm.git / commitdiff