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[ARM64,C++11]: Range'ify loops in the conditional-compare pass.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205988 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jim Grosbach 2014-04-10 21:49:24 +00:00
parent b4dd10a723
commit 13772fb0a7
1 changed files with 25 additions and 27 deletions
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52
lib/Target/ARM64/ARM64ConditionalCompares.cpp
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@ -212,13 +212,14 @@ public:
// Check that all PHIs in Tail are selecting the same value from Head and CmpBB.
// This means that no if-conversion is required when merging CmpBB into Head.
bool SSACCmpConv::trivialTailPHIs() {
for (MachineBasicBlock::iterator I = Tail->begin(), E = Tail->end();
I != E && I->isPHI(); ++I) {
for (auto &I : *Tail) {
if (!I.isPHI())
break;
unsigned HeadReg = 0, CmpBBReg = 0;
// PHI operands come in (VReg, MBB) pairs.
for (unsigned oi = 1, oe = I->getNumOperands(); oi != oe; oi += 2) {
MachineBasicBlock *MBB = I->getOperand(oi + 1).getMBB();
unsigned Reg = I->getOperand(oi).getReg();
for (unsigned oi = 1, oe = I.getNumOperands(); oi != oe; oi += 2) {
MachineBasicBlock *MBB = I.getOperand(oi + 1).getMBB();
unsigned Reg = I.getOperand(oi).getReg();
if (MBB == Head) {
assert((!HeadReg || HeadReg == Reg) && "Inconsistent PHI operands");
HeadReg = Reg;
@ -237,14 +238,15 @@ bool SSACCmpConv::trivialTailPHIs() {
// Assuming that trivialTailPHIs() is true, update the Tail PHIs by simply
// removing the CmpBB operands. The Head operands will be identical.
void SSACCmpConv::updateTailPHIs() {
for (MachineBasicBlock::iterator I = Tail->begin(), E = Tail->end();
I != E && I->isPHI(); ++I) {
for (auto &I : *Tail) {
if (!I.isPHI())
break;
// I is a PHI. It can have multiple entries for CmpBB.
for (unsigned oi = I->getNumOperands(); oi > 2; oi -= 2) {
for (unsigned oi = I.getNumOperands(); oi > 2; oi -= 2) {
// PHI operands are (Reg, MBB) at (oi-2, oi-1).
if (I->getOperand(oi - 1).getMBB() == CmpBB) {
I->RemoveOperand(oi - 1);
I->RemoveOperand(oi - 2);
if (I.getOperand(oi - 1).getMBB() == CmpBB) {
I.RemoveOperand(oi - 1);
I.RemoveOperand(oi - 2);
}
}
}
@ -387,10 +389,8 @@ bool SSACCmpConv::canSpeculateInstrs(MachineBasicBlock *MBB,
// Check all instructions, except the terminators. It is assumed that
// terminators never have side effects or define any used register values.
for (MachineBasicBlock::iterator I = MBB->begin(),
E = MBB->getFirstTerminator();
I != E; ++I) {
if (I->isDebugValue())
for (auto &I : make_range(MBB->begin(), MBB->getFirstTerminator())) {
if (I.isDebugValue())
continue;
if (++InstrCount > BlockInstrLimit && !Stress) {
@ -400,29 +400,29 @@ bool SSACCmpConv::canSpeculateInstrs(MachineBasicBlock *MBB,
}
// There shouldn't normally be any phis in a single-predecessor block.
if (I->isPHI()) {
DEBUG(dbgs() << "Can't hoist: " << *I);
if (I.isPHI()) {
DEBUG(dbgs() << "Can't hoist: " << I);
return false;
}
// Don't speculate loads. Note that it may be possible and desirable to
// speculate GOT or constant pool loads that are guaranteed not to trap,
// but we don't support that for now.
if (I->mayLoad()) {
DEBUG(dbgs() << "Won't speculate load: " << *I);
if (I.mayLoad()) {
DEBUG(dbgs() << "Won't speculate load: " << I);
return false;
}
// We never speculate stores, so an AA pointer isn't necessary.
bool DontMoveAcrossStore = true;
if (!I->isSafeToMove(TII, 0, DontMoveAcrossStore)) {
DEBUG(dbgs() << "Can't speculate: " << *I);
if (!I.isSafeToMove(TII, 0, DontMoveAcrossStore)) {
DEBUG(dbgs() << "Can't speculate: " << I);
return false;
}
// Only CmpMI is allowed to clobber the flags.
if (&*I != CmpMI && I->modifiesRegister(ARM64::CPSR, TRI)) {
DEBUG(dbgs() << "Clobbers flags: " << *I);
if (&I != CmpMI && I.modifiesRegister(ARM64::CPSR, TRI)) {
DEBUG(dbgs() << "Clobbers flags: " << I);
return false;
}
}
@ -906,11 +906,9 @@ bool ARM64ConditionalCompares::runOnMachineFunction(MachineFunction &MF) {
// Visit blocks in dominator tree pre-order. The pre-order enables multiple
// cmp-conversions from the same head block.
// Note that updateDomTree() modifies the children of the DomTree node
// currently being visited. The df_iterator supports that, it doesn't look at
// currently being visited. The df_iterator supports that; it doesn't look at
// child_begin() / child_end() until after a node has been visited.
for (df_iterator<MachineDominatorTree *> I = df_begin(DomTree),
E = df_end(DomTree);
I != E; ++I)
for (auto *I : make_range(df_begin(DomTree), df_end(DomTree)))
if (tryConvert(I->getBlock()))
Changed = true;