- Remove calls to copyKillDeadInfo which is an N^2 function. Instead, propagate kill / dead markers as new instructions are constructed in foldMemoryOperand, convertToThressAddress, etc.
- 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
diff --git a/lib/CodeGen/PHIElimination.cpp b/lib/CodeGen/PHIElimination.cpp
index b50a008..6dbc3dc 100644
--- a/lib/CodeGen/PHIElimination.cpp
+++ b/lib/CodeGen/PHIElimination.cpp
@@ -152,36 +152,44 @@
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 @@
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 @@
"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);