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path: root/lib/CodeGen/PeepholeOptimizer.cpp
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-rw-r--r--lib/CodeGen/PeepholeOptimizer.cpp125
1 files changed, 70 insertions, 55 deletions
diff --git a/lib/CodeGen/PeepholeOptimizer.cpp b/lib/CodeGen/PeepholeOptimizer.cpp
index 28f2d2f9e9..e18d963585 100644
--- a/lib/CodeGen/PeepholeOptimizer.cpp
+++ b/lib/CodeGen/PeepholeOptimizer.cpp
@@ -110,9 +110,9 @@ namespace {
initializePeepholeOptimizerPass(*PassRegistry::getPassRegistry());
}
- virtual bool runOnMachineFunction(MachineFunction &MF);
+ bool runOnMachineFunction(MachineFunction &MF) override;
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
MachineFunctionPass::getAnalysisUsage(AU);
if (Aggressive) {
@@ -133,7 +133,8 @@ namespace {
bool foldImmediate(MachineInstr *MI, MachineBasicBlock *MBB,
SmallSet<unsigned, 4> &ImmDefRegs,
DenseMap<unsigned, MachineInstr*> &ImmDefMIs);
- bool isLoadFoldable(MachineInstr *MI, unsigned &FoldAsLoadDefReg);
+ bool isLoadFoldable(MachineInstr *MI,
+ SmallSet<unsigned, 16> &FoldAsLoadDefCandidates);
};
}
@@ -187,10 +188,8 @@ optimizeExtInstr(MachineInstr *MI, MachineBasicBlock *MBB,
// The source has other uses. See if we can replace the other uses with use of
// the result of the extension.
SmallPtrSet<MachineBasicBlock*, 4> ReachedBBs;
- for (MachineRegisterInfo::use_nodbg_iterator
- UI = MRI->use_nodbg_begin(DstReg), UE = MRI->use_nodbg_end();
- UI != UE; ++UI)
- ReachedBBs.insert(UI->getParent());
+ for (MachineInstr &UI : MRI->use_nodbg_instructions(DstReg))
+ ReachedBBs.insert(UI.getParent());
// Uses that are in the same BB of uses of the result of the instruction.
SmallVector<MachineOperand*, 8> Uses;
@@ -199,11 +198,8 @@ optimizeExtInstr(MachineInstr *MI, MachineBasicBlock *MBB,
SmallVector<MachineOperand*, 8> ExtendedUses;
bool ExtendLife = true;
- for (MachineRegisterInfo::use_nodbg_iterator
- UI = MRI->use_nodbg_begin(SrcReg), UE = MRI->use_nodbg_end();
- UI != UE; ++UI) {
- MachineOperand &UseMO = UI.getOperand();
- MachineInstr *UseMI = &*UI;
+ for (MachineOperand &UseMO : MRI->use_nodbg_operands(SrcReg)) {
+ MachineInstr *UseMI = UseMO.getParent();
if (UseMI == MI)
continue;
@@ -270,11 +266,9 @@ optimizeExtInstr(MachineInstr *MI, MachineBasicBlock *MBB,
// Look for PHI uses of the extended result, we don't want to extend the
// liveness of a PHI input. It breaks all kinds of assumptions down
// stream. A PHI use is expected to be the kill of its source values.
- for (MachineRegisterInfo::use_nodbg_iterator
- UI = MRI->use_nodbg_begin(DstReg), UE = MRI->use_nodbg_end();
- UI != UE; ++UI)
- if (UI->isPHI())
- PHIBBs.insert(UI->getParent());
+ for (MachineInstr &UI : MRI->use_nodbg_instructions(DstReg))
+ if (UI.isPHI())
+ PHIBBs.insert(UI.getParent());
const TargetRegisterClass *RC = MRI->getRegClass(SrcReg);
for (unsigned i = 0, e = Uses.size(); i != e; ++i) {
@@ -496,8 +490,9 @@ bool PeepholeOptimizer::optimizeCopyOrBitcast(MachineInstr *MI) {
/// isLoadFoldable - Check whether MI is a candidate for folding into a later
/// instruction. We only fold loads to virtual registers and the virtual
/// register defined has a single use.
-bool PeepholeOptimizer::isLoadFoldable(MachineInstr *MI,
- unsigned &FoldAsLoadDefReg) {
+bool PeepholeOptimizer::isLoadFoldable(
+ MachineInstr *MI,
+ SmallSet<unsigned, 16> &FoldAsLoadDefCandidates) {
if (!MI->canFoldAsLoad() || !MI->mayLoad())
return false;
const MCInstrDesc &MCID = MI->getDesc();
@@ -505,13 +500,13 @@ bool PeepholeOptimizer::isLoadFoldable(MachineInstr *MI,
return false;
unsigned Reg = MI->getOperand(0).getReg();
- // To reduce compilation time, we check MRI->hasOneUse when inserting
+ // To reduce compilation time, we check MRI->hasOneNonDBGUse when inserting
// loads. It should be checked when processing uses of the load, since
// uses can be removed during peephole.
if (!MI->getOperand(0).getSubReg() &&
TargetRegisterInfo::isVirtualRegister(Reg) &&
- MRI->hasOneUse(Reg)) {
- FoldAsLoadDefReg = Reg;
+ MRI->hasOneNonDBGUse(Reg)) {
+ FoldAsLoadDefCandidates.insert(Reg);
return true;
}
return false;
@@ -561,6 +556,9 @@ bool PeepholeOptimizer::foldImmediate(MachineInstr *MI, MachineBasicBlock *MBB,
}
bool PeepholeOptimizer::runOnMachineFunction(MachineFunction &MF) {
+ if (skipOptnoneFunction(*MF.getFunction()))
+ return false;
+
DEBUG(dbgs() << "********** PEEPHOLE OPTIMIZER **********\n");
DEBUG(dbgs() << "********** Function: " << MF.getName() << '\n');
@@ -574,18 +572,14 @@ bool PeepholeOptimizer::runOnMachineFunction(MachineFunction &MF) {
bool Changed = false;
- SmallPtrSet<MachineInstr*, 8> LocalMIs;
- SmallSet<unsigned, 4> ImmDefRegs;
- DenseMap<unsigned, MachineInstr*> ImmDefMIs;
- unsigned FoldAsLoadDefReg;
for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
MachineBasicBlock *MBB = &*I;
bool SeenMoveImm = false;
- LocalMIs.clear();
- ImmDefRegs.clear();
- ImmDefMIs.clear();
- FoldAsLoadDefReg = 0;
+ SmallPtrSet<MachineInstr*, 8> LocalMIs;
+ SmallSet<unsigned, 4> ImmDefRegs;
+ DenseMap<unsigned, MachineInstr*> ImmDefMIs;
+ SmallSet<unsigned, 16> FoldAsLoadDefCandidates;
for (MachineBasicBlock::iterator
MII = I->begin(), MIE = I->end(); MII != MIE; ) {
@@ -594,16 +588,20 @@ bool PeepholeOptimizer::runOnMachineFunction(MachineFunction &MF) {
++MII;
LocalMIs.insert(MI);
+ // Skip debug values. They should not affect this peephole optimization.
+ if (MI->isDebugValue())
+ continue;
+
// If there exists an instruction which belongs to the following
- // categories, we will discard the load candidate.
- if (MI->isLabel() || MI->isPHI() || MI->isImplicitDef() ||
- MI->isKill() || MI->isInlineAsm() || MI->isDebugValue() ||
+ // categories, we will discard the load candidates.
+ if (MI->isPosition() || MI->isPHI() || MI->isImplicitDef() ||
+ MI->isKill() || MI->isInlineAsm() ||
MI->hasUnmodeledSideEffects()) {
- FoldAsLoadDefReg = 0;
+ FoldAsLoadDefCandidates.clear();
continue;
}
if (MI->mayStore() || MI->isCall())
- FoldAsLoadDefReg = 0;
+ FoldAsLoadDefCandidates.clear();
if (((MI->isBitcast() || MI->isCopy()) && optimizeCopyOrBitcast(MI)) ||
(MI->isCompare() && optimizeCmpInstr(MI, MBB)) ||
@@ -630,26 +628,43 @@ bool PeepholeOptimizer::runOnMachineFunction(MachineFunction &MF) {
// Check whether MI is a load candidate for folding into a later
// instruction. If MI is not a candidate, check whether we can fold an
// earlier load into MI.
- if (!isLoadFoldable(MI, FoldAsLoadDefReg) && FoldAsLoadDefReg) {
- // We need to fold load after optimizeCmpInstr, since optimizeCmpInstr
- // can enable folding by converting SUB to CMP.
- MachineInstr *DefMI = 0;
- MachineInstr *FoldMI = TII->optimizeLoadInstr(MI, MRI,
- FoldAsLoadDefReg, DefMI);
- if (FoldMI) {
- // Update LocalMIs since we replaced MI with FoldMI and deleted DefMI.
- DEBUG(dbgs() << "Replacing: " << *MI);
- DEBUG(dbgs() << " With: " << *FoldMI);
- LocalMIs.erase(MI);
- LocalMIs.erase(DefMI);
- LocalMIs.insert(FoldMI);
- MI->eraseFromParent();
- DefMI->eraseFromParent();
- ++NumLoadFold;
-
- // MI is replaced with FoldMI.
- Changed = true;
- continue;
+ if (!isLoadFoldable(MI, FoldAsLoadDefCandidates) &&
+ !FoldAsLoadDefCandidates.empty()) {
+ const MCInstrDesc &MIDesc = MI->getDesc();
+ for (unsigned i = MIDesc.getNumDefs(); i != MIDesc.getNumOperands();
+ ++i) {
+ const MachineOperand &MOp = MI->getOperand(i);
+ if (!MOp.isReg())
+ continue;
+ unsigned FoldAsLoadDefReg = MOp.getReg();
+ if (FoldAsLoadDefCandidates.count(FoldAsLoadDefReg)) {
+ // We need to fold load after optimizeCmpInstr, since
+ // optimizeCmpInstr can enable folding by converting SUB to CMP.
+ // Save FoldAsLoadDefReg because optimizeLoadInstr() resets it and
+ // we need it for markUsesInDebugValueAsUndef().
+ unsigned FoldedReg = FoldAsLoadDefReg;
+ MachineInstr *DefMI = 0;
+ MachineInstr *FoldMI = TII->optimizeLoadInstr(MI, MRI,
+ FoldAsLoadDefReg,
+ DefMI);
+ if (FoldMI) {
+ // Update LocalMIs since we replaced MI with FoldMI and deleted
+ // DefMI.
+ DEBUG(dbgs() << "Replacing: " << *MI);
+ DEBUG(dbgs() << " With: " << *FoldMI);
+ LocalMIs.erase(MI);
+ LocalMIs.erase(DefMI);
+ LocalMIs.insert(FoldMI);
+ MI->eraseFromParent();
+ DefMI->eraseFromParent();
+ MRI->markUsesInDebugValueAsUndef(FoldedReg);
+ FoldAsLoadDefCandidates.erase(FoldedReg);
+ ++NumLoadFold;
+ // MI is replaced with FoldMI.
+ Changed = true;
+ break;
+ }
+ }
}
}
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-13 14:32:53 +0000