Remove val# defined by a remat'ed def that is now dead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58294 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/PreAllocSplitting.cpp b/lib/CodeGen/PreAllocSplitting.cpp
index 33e3e80..0969440 100644
--- a/lib/CodeGen/PreAllocSplitting.cpp
+++ b/lib/CodeGen/PreAllocSplitting.cpp
@@ -561,6 +561,9 @@
SpillMI = prior(SpillPt);
LIs->InsertMachineInstrInMaps(SpillMI, SpillIndex);
} else if (!PrevSpilled) {
+ if (!DefMI)
+ // Def is dead. Do nothing.
+ return false;
// If it's already split, just restore the value. There is no need to spill
// the def again.
// Check if it's possible to insert a spill after the def MI.
diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp
index 6eeb21c..a60939c 100644
--- a/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -707,6 +707,18 @@
return false;
}
+/// RemoveDeadDef - If a def of a live interval is now determined dead, remove
+/// the val# it defines. If the live interval becomes empty, remove it as well.
+bool SimpleRegisterCoalescing::RemoveDeadDef(LiveInterval &li,
+ MachineInstr *DefMI) {
+ unsigned DefIdx = li_->getDefIndex(li_->getInstructionIndex(DefMI));
+ LiveInterval::iterator MLR = li.FindLiveRangeContaining(DefIdx);
+ if (DefIdx != MLR->valno->def)
+ return false;
+ li.removeValNo(MLR->valno);
+ return removeIntervalIfEmpty(li, li_, tri_);
+}
+
/// PropagateDeadness - Propagate the dead marker to the instruction which
/// defines the val#.
static void PropagateDeadness(LiveInterval &li, MachineInstr *CopyMI,
@@ -2280,6 +2292,7 @@
// Perform a final pass over the instructions and compute spill weights
// and remove identity moves.
+ SmallVector<unsigned, 4> DeadDefs;
for (MachineFunction::iterator mbbi = mf_->begin(), mbbe = mf_->end();
mbbi != mbbe; ++mbbi) {
MachineBasicBlock* mbb = mbbi;
@@ -2313,9 +2326,13 @@
bool isDead = true;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
- if (!MO.isReg() || MO.isDead())
+ if (!MO.isReg())
continue;
unsigned Reg = MO.getReg();
+ if (TargetRegisterInfo::isVirtualRegister(Reg))
+ DeadDefs.push_back(Reg);
+ if (MO.isDead())
+ continue;
if (TargetRegisterInfo::isPhysicalRegister(Reg) ||
!mri_->use_empty(Reg)) {
isDead = false;
@@ -2323,10 +2340,16 @@
}
}
if (isDead) {
+ while (!DeadDefs.empty()) {
+ unsigned DeadDef = DeadDefs.back();
+ DeadDefs.pop_back();
+ RemoveDeadDef(li_->getInterval(DeadDef), MI);
+ }
li_->RemoveMachineInstrFromMaps(mii);
mii = mbbi->erase(mii);
continue;
- }
+ } else
+ DeadDefs.clear();
}
// If the move will be an identity move delete it
diff --git a/lib/CodeGen/SimpleRegisterCoalescing.h b/lib/CodeGen/SimpleRegisterCoalescing.h
index 330c476..abe3929 100644
--- a/lib/CodeGen/SimpleRegisterCoalescing.h
+++ b/lib/CodeGen/SimpleRegisterCoalescing.h
@@ -269,6 +269,11 @@
/// live range is dead. Return true if live interval is removed.
bool ShortenDeadCopySrcLiveRange(LiveInterval &li, MachineInstr *CopyMI);
+ /// RemoveDeadDef - If a def of a live interval is now determined dead,
+ /// remove the val# it defines. If the live interval becomes empty, remove
+ /// it as well.
+ bool RemoveDeadDef(LiveInterval &li, MachineInstr *DefMI);
+
/// lastRegisterUse - Returns the last use of the specific register between
/// cycles Start and End or NULL if there are no uses.
MachineOperand *lastRegisterUse(unsigned Start, unsigned End, unsigned Reg,