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Fast path implicit_def check. 

llvm-svn: 101183
This commit is contained in:
Evan Cheng 2010-04-13 22:13:34 +00:00
parent 6c35893aa6
commit 87585d72a5
1 changed files with 5 additions and 5 deletions
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10
llvm/lib/CodeGen/MachineLICM.cpp
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@ -300,7 +300,7 @@ void MachineLICM::ProcessMI(MachineInstr *MI,
"Not expecting virtual register!");
if (!MO.isDef()) {
if (PhysRegDefs[Reg])
if (Reg && PhysRegDefs[Reg])
// If it's using a non-loop-invariant register, then it's obviously not
// safe to hoist.
HasNonInvariantUse = true;
@ -406,7 +406,7 @@ void MachineLICM::HoistRegionPostRA(MachineDomTreeNode *N) {
MachineInstr *MI = Candidates[i].MI;
for (unsigned j = 0, ee = MI->getNumOperands(); j != ee; ++j) {
const MachineOperand &MO = MI->getOperand(j);
if (!MO.isReg() || MO.isDef())
if (!MO.isReg() || MO.isDef() || !MO.getReg())
continue;
if (PhysRegDefs[MO.getReg()]) {
// If it's using a non-loop-invariant register, then it's obviously
@ -502,6 +502,9 @@ void MachineLICM::HoistRegion(MachineDomTreeNode *N) {
/// candidate for LICM. e.g. If the instruction is a call, then it's obviously
/// not safe to hoist it.
bool MachineLICM::IsLICMCandidate(MachineInstr &I) {
if (I.isImplicitDef())
return false;
const TargetInstrDesc &TID = I.getDesc();
// Ignore stuff that we obviously can't hoist.
@ -620,9 +623,6 @@ bool MachineLICM::isLoadFromConstantMemory(MachineInstr *MI) {
/// IsProfitableToHoist - Return true if it is potentially profitable to hoist
/// the given loop invariant.
bool MachineLICM::IsProfitableToHoist(MachineInstr &MI) {
if (MI.isImplicitDef())
return false;
// FIXME: For now, only hoist re-materilizable instructions. LICM will
// increase register pressure. We want to make sure it doesn't increase
// spilling.