[llvm] r205988 - [ARM64, C++11]: Range'ify loops in the conditional-compare pass.
David Blaikie
dblaikie at gmail.com
Thu Apr 10 15:14:02 PDT 2014
On Thu, Apr 10, 2014 at 2:49 PM, Jim Grosbach <grosbach at apple.com> wrote:
> Author: grosbach
> Date: Thu Apr 10 16:49:24 2014
> New Revision: 205988
>
> URL: http://llvm.org/viewvc/llvm-project?rev=205988&view=rev
> Log:
> [ARM64,C++11]: Range'ify loops in the conditional-compare pass.
>
> Modified:
> llvm/trunk/lib/Target/ARM64/ARM64ConditionalCompares.cpp
>
> Modified: llvm/trunk/lib/Target/ARM64/ARM64ConditionalCompares.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM64/ARM64ConditionalCompares.cpp?rev=205988&r1=205987&r2=205988&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/ARM64/ARM64ConditionalCompares.cpp (original)
> +++ llvm/trunk/lib/Target/ARM64/ARM64ConditionalCompares.cpp Thu Apr 10 16:49:24 2014
> @@ -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(Mac
>
> // 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(Mac
> }
>
> // 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::runOnMach
> // 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)))
Might be nice to add the range function for these two utilities
(df_end/begin - either "dfs" or "df_range" or something more verbose
like "dom_frontiers" (at a guess)?)? (I guess this is why you added
make_range, though - I'd assumed you were just using it to simplify
the implementation of range accessor functions - I'd have a slight
preference of avoiding its use more generally in favor of providing
reusable range accessors or other utilities (range
splitting/merging/etc rather than doing iterator stuff))
> if (tryConvert(I->getBlock()))
> Changed = true;
>
>
>
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