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- Remove calls to copyKillDeadInfo which is an N^2 function. Instead, propagate kill / dead markers as new instructions are constructed in foldMemoryOperand, convertToThressAddress, etc.

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- Also remove LiveVariables::instructionChanged, etc. Replace all calls with cheaper calls which update VarInfo kill list.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53097 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2008-07-03 09:09:37 +00:00
parent f9d0318950
commit 9f1c8317a4
16 changed files with 225 additions and 260 deletions
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lib/CodeGen/PHIElimination.cpp
+23 -17
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@@ -152,36 +152,44 @@ void PNE::LowerAtomicPHINode(MachineBasicBlock &MBB,
unsigned NumSrcs = (MPhi->getNumOperands() - 1) / 2;
unsigned DestReg = MPhi->getOperand(0).getReg();
bool isDead = MPhi->getOperand(0).isDead();
// Create a new register for the incoming PHI arguments.
MachineFunction &MF = *MBB.getParent();
const TargetRegisterClass *RC = MF.getRegInfo().getRegClass(DestReg);
unsigned IncomingReg = MF.getRegInfo().createVirtualRegister(RC);
unsigned IncomingReg = 0;
// Insert a register to register copy at the top of the current block (but
// after any remaining phi nodes) which copies the new incoming register
// into the phi node destination.
const TargetInstrInfo *TII = MF.getTarget().getInstrInfo();
if (isSourceDefinedByImplicitDef(MPhi, MRI))
// If all sources of a PHI node are implicit_def, just emit an implicit_def
// instead of a copy.
BuildMI(MBB, AfterPHIsIt, TII->get(TargetInstrInfo::IMPLICIT_DEF), DestReg);
else
// If all sources of a PHI node are implicit_def, just emit an
// implicit_def instead of a copy.
BuildMI(MBB, AfterPHIsIt,
TII->get(TargetInstrInfo::IMPLICIT_DEF), DestReg);
else {
IncomingReg = MF.getRegInfo().createVirtualRegister(RC);
TII->copyRegToReg(MBB, AfterPHIsIt, DestReg, IncomingReg, RC, RC);
}
// Update live variable information if there is any.
LiveVariables *LV = getAnalysisToUpdate<LiveVariables>();
if (LV) {
MachineInstr *PHICopy = prior(AfterPHIsIt);
// Increment use count of the newly created virtual register.
LV->getVarInfo(IncomingReg).NumUses++;
if (IncomingReg) {
// Increment use count of the newly created virtual register.
LV->getVarInfo(IncomingReg).NumUses++;
// Add information to LiveVariables to know that the incoming value is
// killed. Note that because the value is defined in several places (once
// each for each incoming block), the "def" block and instruction fields for
// the VarInfo is not filled in.
LV->addVirtualRegisterKilled(IncomingReg, PHICopy);
// Add information to LiveVariables to know that the incoming value is
// killed. Note that because the value is defined in several places (once
// each for each incoming block), the "def" block and instruction fields
// for the VarInfo is not filled in.
LV->addVirtualRegisterKilled(IncomingReg, PHICopy);
LV->getVarInfo(IncomingReg).UsedBlocks[MBB.getNumber()] = true;
}
// Since we are going to be deleting the PHI node, if it is the last use of
// any registers, or if the value itself is dead, we need to move this
@@ -189,12 +197,10 @@ void PNE::LowerAtomicPHINode(MachineBasicBlock &MBB,
LV->removeVirtualRegistersKilled(MPhi);
// If the result is dead, update LV.
if (MPhi->registerDefIsDead(DestReg)) {
if (isDead) {
LV->addVirtualRegisterDead(DestReg, PHICopy);
LV->removeVirtualRegistersDead(MPhi);
LV->removeVirtualRegisterDead(DestReg, MPhi);
}
LV->getVarInfo(IncomingReg).UsedBlocks[MBB.getNumber()] = true;
}
// Adjust the VRegPHIUseCount map to account for the removal of this PHI node.
@@ -211,7 +217,7 @@ void PNE::LowerAtomicPHINode(MachineBasicBlock &MBB,
"Machine PHI Operands must all be virtual registers!");
// If source is defined by an implicit def, there is no need to insert a
// copy unless it's the only source.
// copy.
MachineInstr *DefMI = MRI->getVRegDef(SrcReg);
if (DefMI->getOpcode() == TargetInstrInfo::IMPLICIT_DEF) {
ImpDefs.insert(DefMI);