Revert "Remove references to INSERT_SUBREG after de-SSA" r107725.
Buildbot breakage.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107744 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LowerSubregs.cpp b/lib/CodeGen/LowerSubregs.cpp
index eccae52..172e4b5 100644
--- a/lib/CodeGen/LowerSubregs.cpp
+++ b/lib/CodeGen/LowerSubregs.cpp
@@ -54,6 +54,7 @@
private:
bool LowerExtract(MachineInstr *MI);
+ bool LowerInsert(MachineInstr *MI);
bool LowerSubregToReg(MachineInstr *MI);
bool LowerCopy(MachineInstr *MI);
@@ -237,6 +238,90 @@
return true;
}
+bool LowerSubregsInstructionPass::LowerInsert(MachineInstr *MI) {
+ MachineBasicBlock *MBB = MI->getParent();
+ assert((MI->getOperand(0).isReg() && MI->getOperand(0).isDef()) &&
+ (MI->getOperand(1).isReg() && MI->getOperand(1).isUse()) &&
+ (MI->getOperand(2).isReg() && MI->getOperand(2).isUse()) &&
+ MI->getOperand(3).isImm() && "Invalid insert_subreg");
+
+ unsigned DstReg = MI->getOperand(0).getReg();
+#ifndef NDEBUG
+ unsigned SrcReg = MI->getOperand(1).getReg();
+#endif
+ unsigned InsReg = MI->getOperand(2).getReg();
+ unsigned SubIdx = MI->getOperand(3).getImm();
+
+ assert(DstReg == SrcReg && "insert_subreg not a two-address instruction?");
+ assert(SubIdx != 0 && "Invalid index for insert_subreg");
+ unsigned DstSubReg = TRI->getSubReg(DstReg, SubIdx);
+ assert(DstSubReg && "invalid subregister index for register");
+ assert(TargetRegisterInfo::isPhysicalRegister(SrcReg) &&
+ "Insert superreg source must be in a physical register");
+ assert(TargetRegisterInfo::isPhysicalRegister(InsReg) &&
+ "Inserted value must be in a physical register");
+
+ DEBUG(dbgs() << "subreg: CONVERTING: " << *MI);
+
+ if (DstSubReg == InsReg) {
+ // No need to insert an identity copy instruction. If the SrcReg was
+ // <undef>, we need to make sure it is alive by inserting a KILL
+ if (MI->getOperand(1).isUndef() && !MI->getOperand(0).isDead()) {
+ MachineInstrBuilder MIB = BuildMI(*MBB, MI, MI->getDebugLoc(),
+ TII->get(TargetOpcode::KILL), DstReg);
+ if (MI->getOperand(2).isUndef())
+ MIB.addReg(InsReg, RegState::Undef);
+ else
+ MIB.addReg(InsReg, RegState::Kill);
+ } else {
+ DEBUG(dbgs() << "subreg: eliminated!\n");
+ MBB->erase(MI);
+ return true;
+ }
+ } else {
+ // Insert sub-register copy
+ const TargetRegisterClass *TRC0= TRI->getPhysicalRegisterRegClass(DstSubReg);
+ const TargetRegisterClass *TRC1= TRI->getPhysicalRegisterRegClass(InsReg);
+ if (MI->getOperand(2).isUndef())
+ // If the source register being inserted is undef, then this becomes a
+ // KILL.
+ BuildMI(*MBB, MI, MI->getDebugLoc(),
+ TII->get(TargetOpcode::KILL), DstSubReg);
+ else {
+ bool Emitted = TII->copyRegToReg(*MBB, MI, DstSubReg, InsReg, TRC0, TRC1,
+ MI->getDebugLoc());
+ (void)Emitted;
+ assert(Emitted && "Subreg and Dst must be of compatible register class");
+ }
+ MachineBasicBlock::iterator CopyMI = MI;
+ --CopyMI;
+
+ // INSERT_SUBREG is a two-address instruction so it implicitly kills SrcReg.
+ if (!MI->getOperand(1).isUndef())
+ CopyMI->addOperand(MachineOperand::CreateReg(DstReg, false, true, true));
+
+ // Transfer the kill/dead flags, if needed.
+ if (MI->getOperand(0).isDead()) {
+ TransferDeadFlag(MI, DstSubReg, TRI);
+ } else {
+ // Make sure the full DstReg is live after this replacement.
+ CopyMI->addOperand(MachineOperand::CreateReg(DstReg, true, true));
+ }
+
+ // Make sure the inserted register gets killed
+ if (MI->getOperand(2).isKill() && !MI->getOperand(2).isUndef())
+ TransferKillFlag(MI, InsReg, TRI);
+ }
+
+ DEBUG({
+ MachineBasicBlock::iterator dMI = MI;
+ dbgs() << "subreg: " << *(--dMI) << "\n";
+ });
+
+ MBB->erase(MI);
+ return true;
+}
+
bool LowerSubregsInstructionPass::LowerCopy(MachineInstr *MI) {
MachineOperand &DstMO = MI->getOperand(0);
MachineOperand &SrcMO = MI->getOperand(1);
@@ -302,9 +387,10 @@
mi != me;) {
MachineBasicBlock::iterator nmi = llvm::next(mi);
MachineInstr *MI = mi;
- assert(!MI->isInsertSubreg() && "INSERT_SUBREG should no longer appear");
if (MI->isExtractSubreg()) {
MadeChange |= LowerExtract(MI);
+ } else if (MI->isInsertSubreg()) {
+ MadeChange |= LowerInsert(MI);
} else if (MI->isSubregToReg()) {
MadeChange |= LowerSubregToReg(MI);
} else if (MI->isCopy()) {