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[RegisterCoalescer] Add wrapper for Erasing Instructions 

Summary:
      To delete an instruction the coalescer needs to call eraseFromParent()
      on the MachineInstr, insert it in the ErasedInstrs list and update the
      Live Ranges structure. This patch re-factors the code to do all that in
      one function. This will also fix cases where previous code wasn't
      inserting deleted instructions in the ErasedList.

Reviewers: qcolombet, kparzysz

Reviewed By: qcolombet

Subscribers: MatzeB, llvm-commits, qcolombet

Differential Revision: https://reviews.llvm.org/D36204

llvm-svn: 309915
This commit is contained in:
Sameer AbuAsal 2017-08-03 02:41:17 +00:00
parent 993bbbf19e
commit c8befe687f
1 changed files with 16 additions and 14 deletions
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30
llvm/lib/CodeGen/RegisterCoalescer.cpp
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@ -248,6 +248,16 @@ namespace {
}
}
/// Wrapper Method to do all the necessary work when an Instruction is
/// deleted.
/// Optimizations should use this to make sure that deleted instructions
/// are always accounted for.
void deleteInstr(MachineInstr* MI) {
ErasedInstrs.insert(MI);
LIS->RemoveMachineInstrFromMaps(*MI);
MI->eraseFromParent();
}
public:
static char ID; ///< Class identification, replacement for typeinfo
RegisterCoalescer() : MachineFunctionPass(ID) {
@ -797,9 +807,7 @@ bool RegisterCoalescer::removeCopyByCommutingDef(const CoalescerPair &CP,
S.MergeValueNumberInto(SubDVNI, SubBValNo);
}
ErasedInstrs.insert(UseMI);
LIS->RemoveMachineInstrFromMaps(*UseMI);
UseMI->eraseFromParent();
deleteInstr(UseMI);
}
// Extend BValNo by merging in IntA live segments of AValNo. Val# definition
@ -993,10 +1001,8 @@ bool RegisterCoalescer::removePartialRedundancy(const CoalescerPair &CP,
// Note: This is fine to remove the copy before updating the live-ranges.
// While updating the live-ranges, we only look at slot indices and
// never go back to the instruction.
LIS->RemoveMachineInstrFromMaps(CopyMI);
// Mark instructions as deleted.
ErasedInstrs.insert(&CopyMI);
CopyMI.eraseFromParent();
deleteInstr(&CopyMI);
// Update the liveness.
SmallVector<SlotIndex, 8> EndPoints;
@ -1578,8 +1584,7 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
// Eliminate undefs.
if (!CP.isPhys() && eliminateUndefCopy(CopyMI)) {
LIS->RemoveMachineInstrFromMaps(*CopyMI);
CopyMI->eraseFromParent();
deleteInstr(CopyMI);
return false; // Not coalescable.
}
@ -1607,8 +1612,7 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
}
DEBUG(dbgs() << "\tMerged values: " << LI << '\n');
}
LIS->RemoveMachineInstrFromMaps(*CopyMI);
CopyMI->eraseFromParent();
deleteInstr(CopyMI);
return true;
}
@ -1668,8 +1672,7 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
if (!CP.isPartial() && !CP.isPhys()) {
if (adjustCopiesBackFrom(CP, CopyMI) ||
removeCopyByCommutingDef(CP, CopyMI)) {
LIS->RemoveMachineInstrFromMaps(*CopyMI);
CopyMI->eraseFromParent();
deleteInstr(CopyMI);
DEBUG(dbgs() << "\tTrivial!\n");
return true;
}
@ -1855,8 +1858,7 @@ bool RegisterCoalescer::joinReservedPhysReg(CoalescerPair &CP) {
}
}
LIS->RemoveMachineInstrFromMaps(*CopyMI);
CopyMI->eraseFromParent();
deleteInstr(CopyMI);
// We don't track kills for reserved registers.
MRI->clearKillFlags(CP.getSrcReg());