Re-materalized definition instructions may be dead. Whack them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56352 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp
index 0044f06..2f4c8d3 100644
--- a/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -479,6 +479,7 @@
li_->ReplaceMachineInstrInMaps(CopyMI, NewMI);
CopyMI->eraseFromParent();
ReMatCopies.insert(CopyMI);
+ ReMatDefs.insert(DefMI);
++NumReMats;
return true;
}
@@ -2183,6 +2184,7 @@
void SimpleRegisterCoalescing::releaseMemory() {
JoinedCopies.clear();
ReMatCopies.clear();
+ ReMatDefs.clear();
}
static bool isZeroLengthInterval(LiveInterval *li) {
@@ -2291,25 +2293,45 @@
continue;
}
+ // Now check if this is a remat'ed def instruction which is now dead.
+ if (ReMatDefs.count(MI)) {
+ bool isDead = true;
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ const MachineOperand &MO = MI->getOperand(i);
+ if (!MO.isRegister() || MO.isDead())
+ continue;
+ unsigned Reg = MO.getReg();
+ if (TargetRegisterInfo::isPhysicalRegister(Reg) ||
+ !mri_->use_empty(Reg)) {
+ isDead = false;
+ break;
+ }
+ }
+ if (isDead) {
+ li_->RemoveMachineInstrFromMaps(mii);
+ mii = mbbi->erase(mii);
+ }
+ }
+
// If the move will be an identity move delete it
- bool isMove = tii_->isMoveInstr(*mii, SrcReg, DstReg);
+ bool isMove = tii_->isMoveInstr(*MI, SrcReg, DstReg);
if (isMove && SrcReg == DstReg) {
if (li_->hasInterval(SrcReg)) {
LiveInterval &RegInt = li_->getInterval(SrcReg);
// If def of this move instruction is dead, remove its live range
// from the dstination register's live interval.
- if (mii->registerDefIsDead(DstReg)) {
- if (!ShortenDeadCopySrcLiveRange(RegInt, mii))
- ShortenDeadCopyLiveRange(RegInt, mii);
+ if (MI->registerDefIsDead(DstReg)) {
+ if (!ShortenDeadCopySrcLiveRange(RegInt, MI))
+ ShortenDeadCopyLiveRange(RegInt, MI);
}
}
- li_->RemoveMachineInstrFromMaps(mii);
+ li_->RemoveMachineInstrFromMaps(MI);
mii = mbbi->erase(mii);
++numPeep;
} else if (!isMove || !TurnCopyIntoImpDef(mii, mbb, DstReg, SrcReg)) {
SmallSet<unsigned, 4> UniqueUses;
- for (unsigned i = 0, e = mii->getNumOperands(); i != e; ++i) {
- const MachineOperand &mop = mii->getOperand(i);
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ const MachineOperand &mop = MI->getOperand(i);
if (mop.isRegister() && mop.getReg() &&
TargetRegisterInfo::isVirtualRegister(mop.getReg())) {
unsigned reg = mop.getReg();