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Enable cross register class coalescing.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76281 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2009-07-18 02:10:10 +00:00
parent 5a206ee7ed
commit 5248468473
10 changed files with 198 additions and 19 deletions
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39
lib/CodeGen/VirtRegRewriter.cpp
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@@ -1344,6 +1344,31 @@ private:
++NumStores;
}
/// isSafeToDelete - Return true if this instruction doesn't produce any side
/// effect and all of its defs are dead.
static bool isSafeToDelete(MachineInstr &MI) {
const TargetInstrDesc &TID = MI.getDesc();
if (TID.mayLoad() || TID.mayStore() || TID.isCall() || TID.isTerminator() ||
TID.isCall() || TID.isBarrier() || TID.isReturn() ||
TID.hasUnmodeledSideEffects())
return false;
if (TID.getImplicitDefs())
return false;
for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI.getOperand(i);
if (!MO.isReg() || !MO.getReg())
continue;
if (MO.isDef() && !MO.isDead())
return false;
if (MO.isUse() && MO.isKill())
// FIXME: We can't remove kill markers or else the scavenger will assert.
// An alternative is to add a ADD pseudo instruction to replace kill
// markers.
return false;
}
return true;
}
/// TransferDeadness - A identity copy definition is dead and it's being
/// removed. Find the last def or use and mark it as dead / kill.
void TransferDeadness(MachineBasicBlock *MBB, unsigned CurDist,
@@ -1385,9 +1410,7 @@ private:
if (LastUD->isDef()) {
// If the instruction has no side effect, delete it and propagate
// backward further. Otherwise, mark is dead and we are done.
const TargetInstrDesc &TID = LastUDMI->getDesc();
if (TID.mayStore() || TID.isCall() || TID.isTerminator() ||
TID.hasUnmodeledSideEffects()) {
if (!isSafeToDelete(*LastUDMI)) {
LastUD->setIsDead();
break;
}
@@ -2170,7 +2193,15 @@ private:
}
}
ProcessNextInst:
DistanceMap.insert(std::make_pair(&MI, Dist++));
// Delete dead instructions without side effects.
if (!Erased && !BackTracked && isSafeToDelete(MI)) {
InvalidateKills(MI, TRI, RegKills, KillOps);
VRM.RemoveMachineInstrFromMaps(&MI);
MBB.erase(&MI);
Erased = true;
}
if (!Erased)
DistanceMap.insert(std::make_pair(&MI, Dist++));
if (!Erased && !BackTracked) {
for (MachineBasicBlock::iterator II = &MI; II != NextMII; ++II)
UpdateKills(*II, TRI, RegKills, KillOps);