//===----------------------------------------------------------------------===//
#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineMemOperand.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
MachineBasicBlock::iterator I,
unsigned DestReg,
unsigned SubIdx,
- const MachineInstr *Orig) const {
+ const MachineInstr *Orig,
+ const TargetRegisterInfo *TRI) const {
MachineInstr *MI = MBB.getParent()->CloneMachineInstr(Orig);
MachineOperand &MO = MI->getOperand(0);
- MO.setReg(DestReg);
- MO.setSubReg(SubIdx);
+ if (TargetRegisterInfo::isVirtualRegister(DestReg)) {
+ MO.setReg(DestReg);
+ MO.setSubReg(SubIdx);
+ } else if (SubIdx) {
+ MO.setReg(TRI->getSubReg(DestReg, SubIdx));
+ } else {
+ MO.setReg(DestReg);
+ }
MBB.insert(I, MI);
}
-bool TargetInstrInfoImpl::isDeadInstruction(const MachineInstr *MI) const {
- const TargetInstrDesc &TID = MI->getDesc();
- if (TID.mayLoad() || TID.mayStore() || TID.isCall() || TID.isTerminator() ||
- TID.isCall() || TID.isBarrier() || TID.isReturn() ||
- TID.hasUnmodeledSideEffects())
+bool
+TargetInstrInfoImpl::isIdentical(const MachineInstr *MI,
+ const MachineInstr *Other,
+ const MachineRegisterInfo *MRI) const {
+ if (MI->getOpcode() != Other->getOpcode() ||
+ MI->getNumOperands() != Other->getNumOperands())
return false;
+
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
- if (!MO.isReg() || !MO.getReg())
+ const MachineOperand &OMO = Other->getOperand(i);
+ if (MO.isReg() && MO.isDef()) {
+ assert(OMO.isReg() && OMO.isDef());
+ unsigned Reg = MO.getReg();
+ if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
+ if (Reg != OMO.getReg())
+ return false;
+ } else if (MRI->getRegClass(MO.getReg()) !=
+ MRI->getRegClass(OMO.getReg()))
+ return false;
+
continue;
- if (MO.isDef() && !MO.isDead())
- return false;
- if (MO.isUse() && MO.isKill())
- // FIXME: We can't remove kill markers or else the scavenger will assert.
- // An alternative is to add a ADD pseudo instruction to replace kill
- // markers.
+ }
+
+ if (!MO.isIdenticalTo(OMO))
return false;
}
+
return true;
}
"Folded a use to a non-load!");
const MachineFrameInfo &MFI = *MF.getFrameInfo();
assert(MFI.getObjectOffset(FrameIndex) != -1);
- MachineMemOperand MMO(PseudoSourceValue::getFixedStack(FrameIndex),
- Flags,
- MFI.getObjectOffset(FrameIndex),
- MFI.getObjectSize(FrameIndex),
- MFI.getObjectAlignment(FrameIndex));
+ MachineMemOperand *MMO =
+ MF.getMachineMemOperand(PseudoSourceValue::getFixedStack(FrameIndex),
+ Flags, /*Offset=*/0,
+ MFI.getObjectSize(FrameIndex),
+ MFI.getObjectAlignment(FrameIndex));
NewMI->addMemOperand(MF, MMO);
return NewMI;
if (!NewMI) return 0;
// Copy the memoperands from the load to the folded instruction.
- for (std::list<MachineMemOperand>::iterator I = LoadMI->memoperands_begin(),
- E = LoadMI->memoperands_end(); I != E; ++I)
- NewMI->addMemOperand(MF, *I);
+ NewMI->setMemRefs(LoadMI->memoperands_begin(),
+ LoadMI->memoperands_end());
return NewMI;
}
+
+bool
+TargetInstrInfo::isReallyTriviallyReMaterializableGeneric(const MachineInstr *
+ MI,
+ AliasAnalysis *
+ AA) const {
+ const MachineFunction &MF = *MI->getParent()->getParent();
+ const MachineRegisterInfo &MRI = MF.getRegInfo();
+ const TargetMachine &TM = MF.getTarget();
+ const TargetInstrInfo &TII = *TM.getInstrInfo();
+ const TargetRegisterInfo &TRI = *TM.getRegisterInfo();
+
+ // A load from a fixed stack slot can be rematerialized. This may be
+ // redundant with subsequent checks, but it's target-independent,
+ // simple, and a common case.
+ int FrameIdx = 0;
+ if (TII.isLoadFromStackSlot(MI, FrameIdx) &&
+ MF.getFrameInfo()->isImmutableObjectIndex(FrameIdx))
+ return true;
+
+ const TargetInstrDesc &TID = MI->getDesc();
+
+ // Avoid instructions obviously unsafe for remat.
+ if (TID.hasUnmodeledSideEffects() || TID.isNotDuplicable() ||
+ TID.mayStore())
+ return false;
+
+ // Avoid instructions which load from potentially varying memory.
+ if (TID.mayLoad() && !MI->isInvariantLoad(AA))
+ return false;
+
+ // If any of the registers accessed are non-constant, conservatively assume
+ // the instruction is not rematerializable.
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ const MachineOperand &MO = MI->getOperand(i);
+ if (!MO.isReg()) continue;
+ unsigned Reg = MO.getReg();
+ if (Reg == 0)
+ continue;
+
+ // Check for a well-behaved physical register.
+ if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
+ if (MO.isUse()) {
+ // If the physreg has no defs anywhere, it's just an ambient register
+ // and we can freely move its uses. Alternatively, if it's allocatable,
+ // it could get allocated to something with a def during allocation.
+ if (!MRI.def_empty(Reg))
+ return false;
+ BitVector AllocatableRegs = TRI.getAllocatableSet(MF, 0);
+ if (AllocatableRegs.test(Reg))
+ return false;
+ // Check for a def among the register's aliases too.
+ for (const unsigned *Alias = TRI.getAliasSet(Reg); *Alias; ++Alias) {
+ unsigned AliasReg = *Alias;
+ if (!MRI.def_empty(AliasReg))
+ return false;
+ if (AllocatableRegs.test(AliasReg))
+ return false;
+ }
+ } else {
+ // A physreg def. We can't remat it.
+ return false;
+ }
+ continue;
+ }
+
+ // Only allow one virtual-register def, and that in the first operand.
+ if (MO.isDef() != (i == 0))
+ return false;
+
+ // For the def, it should be the only def of that register.
+ if (MO.isDef() && (llvm::next(MRI.def_begin(Reg)) != MRI.def_end() ||
+ MRI.isLiveIn(Reg)))
+ return false;
+
+ // Don't allow any virtual-register uses. Rematting an instruction with
+ // virtual register uses would length the live ranges of the uses, which
+ // is not necessarily a good idea, certainly not "trivial".
+ if (MO.isUse())
+ return false;
+ }
+
+ // Everything checked out.
+ return true;
+}
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