[llvm] r347190 - [LICM] Make LICM able to hoist phis
Benjamin Kramer via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 19 08:54:58 PST 2018
This crashes clang on the attached file. I reverted the change in r347225
$ clang -O3 -fexperimental-new-pass-manager t.i -w
Instruction does not dominate all uses!
%spec.select = zext i1 %not.tobool to i64
%d = getelementptr inbounds [2 x %struct.b], [2 x %struct.b]* %g, i64 0,
i64 %spec.select, i32 1
in function e
fatal error: error in backend: Broken function found, compilation aborted!
On Mon, Nov 19, 2018 at 12:33 PM John Brawn via llvm-commits <
llvm-commits at lists.llvm.org> wrote:
> Author: john.brawn
> Date: Mon Nov 19 03:31:24 2018
> New Revision: 347190
>
> URL: http://llvm.org/viewvc/llvm-project?rev=347190&view=rev
> Log:
> [LICM] Make LICM able to hoist phis
>
> The general approach taken is to make note of loop invariant branches,
> then when
> we see something conditional on that branch, such as a phi, we create a
> copy of
> the branch and (empty versions of) its successors and hoist using that.
>
> This has no impact by itself that I've been able to see, as LICM typically
> doesn't see such phis as they will have been converted into selects by the
> time
> LICM is run, but once we start doing phi-to-select conversion later it
> will be
> important.
>
> Differential Revision: https://reviews.llvm.org/D52827
>
> Added:
> llvm/trunk/test/Transforms/LICM/hoist-phi.ll
> Modified:
> llvm/trunk/lib/Transforms/Scalar/LICM.cpp
>
> llvm/trunk/test/Transforms/LoopVectorize/invariant-store-vectorization.ll
>
> Modified: llvm/trunk/lib/Transforms/Scalar/LICM.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LICM.cpp?rev=347190&r1=347189&r2=347190&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Scalar/LICM.cpp (original)
> +++ llvm/trunk/lib/Transforms/Scalar/LICM.cpp Mon Nov 19 03:31:24 2018
> @@ -31,6 +31,7 @@
>
> //===----------------------------------------------------------------------===//
>
> #include "llvm/Transforms/Scalar/LICM.h"
> +#include "llvm/ADT/SetOperations.h"
> #include "llvm/ADT/Statistic.h"
> #include "llvm/Analysis/AliasAnalysis.h"
> #include "llvm/Analysis/AliasSetTracker.h"
> @@ -41,6 +42,7 @@
> #include "llvm/Analysis/GuardUtils.h"
> #include "llvm/Analysis/Loads.h"
> #include "llvm/Analysis/LoopInfo.h"
> +#include "llvm/Analysis/LoopIterator.h"
> #include "llvm/Analysis/LoopPass.h"
> #include "llvm/Analysis/MemoryBuiltins.h"
> #include "llvm/Analysis/MemorySSA.h"
> @@ -75,6 +77,8 @@ using namespace llvm;
>
> #define DEBUG_TYPE "licm"
>
> +STATISTIC(NumCreatedBlocks, "Number of blocks created");
> +STATISTIC(NumClonedBranches, "Number of branches cloned");
> STATISTIC(NumSunk, "Number of instructions sunk out of loop");
> STATISTIC(NumHoisted, "Number of instructions hoisted out of loop");
> STATISTIC(NumMovedLoads, "Number of load insts hoisted or sunk");
> @@ -103,7 +107,7 @@ static bool isNotUsedOrFreeInLoop(const
> const LoopSafetyInfo *SafetyInfo,
> TargetTransformInfo *TTI, bool
> &FreeInLoop);
> static void hoist(Instruction &I, const DominatorTree *DT, const Loop
> *CurLoop,
> - ICFLoopSafetyInfo *SafetyInfo,
> + BasicBlock *Dest, ICFLoopSafetyInfo *SafetyInfo,
> OptimizationRemarkEmitter *ORE);
> static bool sink(Instruction &I, LoopInfo *LI, DominatorTree *DT,
> const Loop *CurLoop, ICFLoopSafetyInfo *SafetyInfo,
> @@ -437,6 +441,225 @@ bool llvm::sinkRegion(DomTreeNode *N, Al
> return Changed;
> }
>
> +// This is a helper class for hoistRegion to make it able to hoist
> control flow
> +// in order to be able to hoist phis. The way this works is that we
> initially
> +// start hoisting to the loop preheader, and when we see a loop invariant
> branch
> +// we make note of this. When we then come to hoist an instruction that's
> +// conditional on such a branch we duplicate the branch and the relevant
> control
> +// flow, then hoist the instruction into the block corresponding to its
> original
> +// block in the duplicated control flow.
> +class ControlFlowHoister {
> +private:
> + // Information about the loop we are hoisting from
> + LoopInfo *LI;
> + DominatorTree *DT;
> + Loop *CurLoop;
> +
> + // A map of blocks in the loop to the block their instructions will be
> hoisted
> + // to.
> + DenseMap<BasicBlock *, BasicBlock *> HoistDestinationMap;
> +
> + // The branches that we can hoist, mapped to the block that marks a
> + // convergence point of their control flow.
> + DenseMap<BranchInst *, BasicBlock *> HoistableBranches;
> +
> +public:
> + ControlFlowHoister(LoopInfo *LI, DominatorTree *DT, Loop *CurLoop)
> + : LI(LI), DT(DT), CurLoop(CurLoop) {}
> +
> + void registerPossiblyHoistableBranch(BranchInst *BI) {
> + // We can only hoist conditional branches with loop invariant
> operands.
> + if (!BI->isConditional() || !CurLoop->hasLoopInvariantOperands(BI))
> + return;
> +
> + // The branch destinations need to be in the loop, and we don't gain
> + // anything by duplicating conditional branches with duplicate
> successors,
> + // as it's essentially the same as an unconditional branch.
> + BasicBlock *TrueDest = BI->getSuccessor(0);
> + BasicBlock *FalseDest = BI->getSuccessor(1);
> + if (!CurLoop->contains(TrueDest) || !CurLoop->contains(FalseDest) ||
> + TrueDest == FalseDest)
> + return;
> +
> + // We can hoist BI if one branch destination is the successor of the
> other,
> + // or both have common successor which we check by seeing if the
> + // intersection of their successors is non-empty.
> + // TODO: This could be expanded to allowing branches where both ends
> + // eventually converge to a single block.
> + SmallPtrSet<BasicBlock *, 4> TrueDestSucc, FalseDestSucc;
> + TrueDestSucc.insert(succ_begin(TrueDest), succ_end(TrueDest));
> + FalseDestSucc.insert(succ_begin(FalseDest), succ_end(FalseDest));
> + BasicBlock *CommonSucc = nullptr;
> + if (TrueDestSucc.count(FalseDest)) {
> + CommonSucc = FalseDest;
> + } else if (FalseDestSucc.count(TrueDest)) {
> + CommonSucc = TrueDest;
> + } else {
> + set_intersect(TrueDestSucc, FalseDestSucc);
> + // If there's one common successor use that.
> + if (TrueDestSucc.size() == 1)
> + CommonSucc = *TrueDestSucc.begin();
> + // If there's more than one pick whichever appears first in the
> block list
> + // (we can't use the value returned by TrueDestSucc.begin() as it's
> + // unpredicatable which element gets returned).
> + else if (!TrueDestSucc.empty()) {
> + Function *F = TrueDest->getParent();
> + auto IsSucc = [&](BasicBlock &BB) { return
> TrueDestSucc.count(&BB); };
> + auto It = std::find_if(F->begin(), F->end(), IsSucc);
> + assert(It != F->end() && "Could not find successor in function");
> + CommonSucc = &*It;
> + }
> + }
> + // The common successor has to be dominated by the branch, as
> otherwise
> + // there will be some other path to the successor that will not be
> + // controlled by this branch so any phi we hoist would be controlled
> by the
> + // wrong condition. This also takes care of avoiding hoisting of loop
> back
> + // edges.
> + // TODO: In some cases this could be relaxed if the successor is
> dominated
> + // by another block that's been hoisted and we can guarantee that the
> + // control flow has been replicated exactly.
> + if (CommonSucc && DT->dominates(BI, CommonSucc))
> + HoistableBranches[BI] = CommonSucc;
> + }
> +
> + bool canHoistPHI(PHINode *PN) {
> + // The phi must have loop invariant operands.
> + if (!CurLoop->hasLoopInvariantOperands(PN))
> + return false;
> + // We can hoist phis if the block they are in is the target of
> hoistable
> + // branches which cover all of the predecessors of the block.
> + SmallPtrSet<BasicBlock *, 8> PredecessorBlocks;
> + BasicBlock *BB = PN->getParent();
> + for (BasicBlock *PredBB : predecessors(BB))
> + PredecessorBlocks.insert(PredBB);
> + // If we have less predecessor blocks than predecessors then the phi
> will
> + // have more than one incoming value for the same block which we can't
> + // handle.
> + // TODO: This could be handled be erasing some of the duplicate
> incoming
> + // values.
> + if (PredecessorBlocks.size() != pred_size(BB))
> + return false;
> + for (auto &Pair : HoistableBranches) {
> + if (Pair.second == BB) {
> + // Which blocks are predecessors via this branch depends on if the
> + // branch is triangle-like or diamond-like.
> + if (Pair.first->getSuccessor(0) == BB) {
> + PredecessorBlocks.erase(Pair.first->getParent());
> + PredecessorBlocks.erase(Pair.first->getSuccessor(1));
> + } else if (Pair.first->getSuccessor(1) == BB) {
> + PredecessorBlocks.erase(Pair.first->getParent());
> + PredecessorBlocks.erase(Pair.first->getSuccessor(0));
> + } else {
> + PredecessorBlocks.erase(Pair.first->getSuccessor(0));
> + PredecessorBlocks.erase(Pair.first->getSuccessor(1));
> + }
> + }
> + }
> + // PredecessorBlocks will now be empty if for every predecessor of BB
> we
> + // found a hoistable branch source.
> + return PredecessorBlocks.empty();
> + }
> +
> + BasicBlock *getOrCreateHoistedBlock(BasicBlock *BB) {
> + // If BB has already been hoisted, return that
> + if (HoistDestinationMap.count(BB))
> + return HoistDestinationMap[BB];
> +
> + // Check if this block is conditional based on a pending branch
> + auto HasBBAsSuccessor =
> + [&](DenseMap<BranchInst *, BasicBlock *>::value_type &Pair) {
> + return BB != Pair.second && (Pair.first->getSuccessor(0) == BB
> ||
> + Pair.first->getSuccessor(1) == BB);
> + };
> + auto It = std::find_if(HoistableBranches.begin(),
> HoistableBranches.end(),
> + HasBBAsSuccessor);
> +
> + // If not involved in a pending branch, hoist to preheader
> + BasicBlock *InitialPreheader = CurLoop->getLoopPreheader();
> + if (It == HoistableBranches.end()) {
> + LLVM_DEBUG(dbgs() << "LICM using " << InitialPreheader->getName()
> + << " as hoist destination for " << BB->getName()
> + << "\n");
> + HoistDestinationMap[BB] = InitialPreheader;
> + return InitialPreheader;
> + }
> + BranchInst *BI = It->first;
> + assert(std::find_if(++It, HoistableBranches.end(), HasBBAsSuccessor)
> ==
> + HoistableBranches.end() &&
> + "BB is expected to be the target of at most one branch");
> +
> + LLVMContext &C = BB->getContext();
> + BasicBlock *TrueDest = BI->getSuccessor(0);
> + BasicBlock *FalseDest = BI->getSuccessor(1);
> + BasicBlock *CommonSucc = HoistableBranches[BI];
> + BasicBlock *HoistTarget = getOrCreateHoistedBlock(BI->getParent());
> +
> + // Create hoisted versions of blocks that currently don't have them
> + auto CreateHoistedBlock = [&](BasicBlock *Orig) {
> + if (HoistDestinationMap.count(Orig))
> + return HoistDestinationMap[Orig];
> + BasicBlock *New =
> + BasicBlock::Create(C, Orig->getName() + ".licm",
> Orig->getParent());
> + HoistDestinationMap[Orig] = New;
> + DT->addNewBlock(New, HoistTarget);
> + if (CurLoop->getParentLoop())
> + CurLoop->getParentLoop()->addBasicBlockToLoop(New, *LI);
> + ++NumCreatedBlocks;
> + LLVM_DEBUG(dbgs() << "LICM created " << New->getName()
> + << " as hoist destination for " << Orig->getName()
> + << "\n");
> + return New;
> + };
> + BasicBlock *HoistTrueDest = CreateHoistedBlock(TrueDest);
> + BasicBlock *HoistFalseDest = CreateHoistedBlock(FalseDest);
> + BasicBlock *HoistCommonSucc = CreateHoistedBlock(CommonSucc);
> +
> + // Link up these blocks with branches.
> + if (!HoistCommonSucc->getTerminator()) {
> + // The new common successor we've generated will branch to whatever
> that
> + // hoist target branched to.
> + BasicBlock *TargetSucc = HoistTarget->getSingleSuccessor();
> + assert(TargetSucc && "Expected hoist target to have a single
> successor");
> + HoistCommonSucc->moveBefore(TargetSucc);
> + BranchInst::Create(TargetSucc, HoistCommonSucc);
> + }
> + if (!HoistTrueDest->getTerminator()) {
> + HoistTrueDest->moveBefore(HoistCommonSucc);
> + BranchInst::Create(HoistCommonSucc, HoistTrueDest);
> + }
> + if (!HoistFalseDest->getTerminator()) {
> + HoistFalseDest->moveBefore(HoistCommonSucc);
> + BranchInst::Create(HoistCommonSucc, HoistFalseDest);
> + }
> +
> + // If BI is being cloned to what was originally the preheader then
> + // HoistCommonSucc will now be the new preheader.
> + if (HoistTarget == InitialPreheader) {
> + // Phis in the loop header now need to use the new preheader.
> + InitialPreheader->replaceSuccessorsPhiUsesWith(HoistCommonSucc);
> + // The new preheader dominates the loop header.
> + DomTreeNode *PreheaderNode = DT->getNode(HoistCommonSucc);
> + DomTreeNode *HeaderNode = DT->getNode(CurLoop->getHeader());
> + DT->changeImmediateDominator(HeaderNode, PreheaderNode);
> + // The preheader hoist destination is now the new preheader, with
> the
> + // exception of the hoist destination of this branch.
> + for (auto &Pair : HoistDestinationMap)
> + if (Pair.second == InitialPreheader && Pair.first !=
> BI->getParent())
> + Pair.second = HoistCommonSucc;
> + }
> +
> + // Now finally clone BI.
> + ReplaceInstWithInst(
> + HoistTarget->getTerminator(),
> + BranchInst::Create(HoistTrueDest, HoistFalseDest,
> BI->getCondition()));
> + ++NumClonedBranches;
> +
> + assert(CurLoop->getLoopPreheader() &&
> + "Hoisting blocks should not have destroyed preheader");
> + return HoistDestinationMap[BB];
> + }
> +};
> +
> /// Walk the specified region of the CFG (defined by all blocks dominated
> by
> /// the specified block, and that are in the current loop) in depth first
> /// order w.r.t the DominatorTree. This allows us to visit definitions
> before
> @@ -451,13 +674,23 @@ bool llvm::hoistRegion(DomTreeNode *N, A
> CurLoop != nullptr && CurAST != nullptr && SafetyInfo != nullptr
> &&
> "Unexpected input to hoistRegion");
>
> - // We want to visit parents before children. We will enque all the
> parents
> - // before their children in the worklist and process the worklist in
> order.
> - SmallVector<DomTreeNode *, 16> Worklist = collectChildrenInLoop(N,
> CurLoop);
> + ControlFlowHoister CFH(LI, DT, CurLoop);
>
> + // Keep track of instructions that have been hoisted, as they may need
> to be
> + // re-hoisted if they end up not dominating all of their uses.
> + SmallVector<Instruction *, 16> HoistedInstructions;
> +
> + // Record what the original preheader is, as we'll need it later if we
> need to
> + // re-hoist instructions.
> + BasicBlock *OriginalPreheader = CurLoop->getLoopPreheader();
> +
> + // For PHI hoisting to work we need to hoist blocks before their
> successors.
> + // We can do this by iterating through the blocks in the loop in reverse
> + // post-order.
> + LoopBlocksRPO Worklist(CurLoop);
> + Worklist.perform(LI);
> bool Changed = false;
> - for (DomTreeNode *DTN : Worklist) {
> - BasicBlock *BB = DTN->getBlock();
> + for (BasicBlock *BB : Worklist) {
> // Only need to process the contents of this block if it is not part
> of a
> // subloop (which would already have been processed).
> if (inSubLoop(BB, CurLoop, LI))
> @@ -483,13 +716,16 @@ bool llvm::hoistRegion(DomTreeNode *N, A
> // Try hoisting the instruction out to the preheader. We can only
> do
> // this if all of the operands of the instruction are loop
> invariant and
> // if it is safe to hoist the instruction.
> - //
> + // TODO: It may be safe to hoist if we are hoisting to a
> conditional block
> + // and we have accurately duplicated the control flow from the loop
> header
> + // to that block.
> if (CurLoop->hasLoopInvariantOperands(&I) &&
> canSinkOrHoistInst(I, AA, DT, CurLoop, CurAST, true, ORE) &&
> isSafeToExecuteUnconditionally(
> I, DT, CurLoop, SafetyInfo, ORE,
> CurLoop->getLoopPreheader()->getTerminator())) {
> - hoist(I, DT, CurLoop, SafetyInfo, ORE);
> + hoist(I, DT, CurLoop, CFH.getOrCreateHoistedBlock(BB),
> SafetyInfo, ORE);
> + HoistedInstructions.push_back(&I);
> Changed = true;
> continue;
> }
> @@ -514,7 +750,9 @@ bool llvm::hoistRegion(DomTreeNode *N, A
> I.replaceAllUsesWith(Product);
> eraseInstruction(I, *SafetyInfo, CurAST);
>
> - hoist(*ReciprocalDivisor, DT, CurLoop, SafetyInfo, ORE);
> + hoist(*ReciprocalDivisor, DT, CurLoop,
> CFH.getOrCreateHoistedBlock(BB),
> + SafetyInfo, ORE);
> + HoistedInstructions.push_back(ReciprocalDivisor);
> Changed = true;
> continue;
> }
> @@ -526,13 +764,58 @@ bool llvm::hoistRegion(DomTreeNode *N, A
> CurLoop->hasLoopInvariantOperands(&I) &&
> SafetyInfo->isGuaranteedToExecute(I, DT, CurLoop) &&
> SafetyInfo->doesNotWriteMemoryBefore(I, CurLoop)) {
> - hoist(I, DT, CurLoop, SafetyInfo, ORE);
> + hoist(I, DT, CurLoop, CFH.getOrCreateHoistedBlock(BB),
> SafetyInfo, ORE);
> + HoistedInstructions.push_back(&I);
> Changed = true;
> continue;
> }
> +
> + if (PHINode *PN = dyn_cast<PHINode>(&I)) {
> + if (CFH.canHoistPHI(PN)) {
> + // Redirect incoming blocks first to ensure that we create
> hoisted
> + // versions of those blocks before we hoist the phi.
> + for (unsigned int i = 0; i < PN->getNumIncomingValues(); ++i)
> + PN->setIncomingBlock(
> + i, CFH.getOrCreateHoistedBlock(PN->getIncomingBlock(i)));
> + hoist(*PN, DT, CurLoop, CFH.getOrCreateHoistedBlock(BB),
> SafetyInfo,
> + ORE);
> + assert(DT->dominates(PN, BB) && "Conditional PHIs not
> expected");
> + Changed = true;
> + continue;
> + }
> + }
> +
> + // Remember possibly hoistable branches so we can actually hoist
> them
> + // later if needed.
> + if (BranchInst *BI = dyn_cast<BranchInst>(&I))
> + CFH.registerPossiblyHoistableBranch(BI);
> + }
> + }
> +
> + // If we hoisted instructions to a conditional block they may not
> dominate
> + // their uses that weren't hoisted (such as phis where some operands
> are not
> + // loop invariant). If so make them unconditional by moving them to the
> end of
> + // the original preheader, which is guaranteed to dominate everything
> in the
> + // loop. We iterate through the instructions in reverse order which
> ensures
> + // that when we rehoist an instruction we rehoist its operands.
> + Instruction *HoistPoint = OriginalPreheader->getTerminator();
> + for (Instruction *I : reverse(HoistedInstructions)) {
> + if (!llvm::all_of(I->uses(), [&](Use &U) { return DT->dominates(I,
> U); })) {
> + LLVM_DEBUG(dbgs() << "LICM rehoisting to " <<
> OriginalPreheader->getName()
> + << ": " << *I << "\n");
> + moveInstructionBefore(*I, *HoistPoint, *SafetyInfo);
> + HoistPoint = I;
> + Changed = true;
> }
> }
>
> + // Now that we've finished hoisting make sure that LI and DT are still
> valid.
> +#ifndef NDEBUG
> + assert(DT->verify(DominatorTree::VerificationLevel::Fast) &&
> + "Dominator tree verification failed");
> + LI->verify(*DT);
> +#endif
> +
> return Changed;
> }
>
> @@ -1100,9 +1383,9 @@ static bool sink(Instruction &I, LoopInf
> /// is safe to hoist, this instruction is called to do the dirty work.
> ///
> static void hoist(Instruction &I, const DominatorTree *DT, const Loop
> *CurLoop,
> - ICFLoopSafetyInfo *SafetyInfo,
> OptimizationRemarkEmitter *ORE) {
> - auto *Preheader = CurLoop->getLoopPreheader();
> - LLVM_DEBUG(dbgs() << "LICM hoisting to " << Preheader->getName() << ":
> " << I
> + BasicBlock *Dest, ICFLoopSafetyInfo *SafetyInfo,
> + OptimizationRemarkEmitter *ORE) {
> + LLVM_DEBUG(dbgs() << "LICM hoisting to " << Dest->getName() << ": " << I
> << "\n");
> ORE->emit([&]() {
> return OptimizationRemark(DEBUG_TYPE, "Hoisted", &I) << "hoisting "
> @@ -1120,8 +1403,12 @@ static void hoist(Instruction &I, const
> !SafetyInfo->isGuaranteedToExecute(I, DT, CurLoop))
> I.dropUnknownNonDebugMetadata();
>
> - // Move the new node to the Preheader, before its terminator.
> - moveInstructionBefore(I, *Preheader->getTerminator(), *SafetyInfo);
> + if (isa<PHINode>(I))
> + // Move the new node to the end of the phi list in the destination
> block.
> + moveInstructionBefore(I, *Dest->getFirstNonPHI(), *SafetyInfo);
> + else
> + // Move the new node to the destination block, before its terminator.
> + moveInstructionBefore(I, *Dest->getTerminator(), *SafetyInfo);
>
> // Do not retain debug locations when we are moving instructions to
> different
> // basic blocks, because we want to avoid jumpy line tables. Calls,
> however,
>
> Added: llvm/trunk/test/Transforms/LICM/hoist-phi.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LICM/hoist-phi.ll?rev=347190&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/Transforms/LICM/hoist-phi.ll (added)
> +++ llvm/trunk/test/Transforms/LICM/hoist-phi.ll Mon Nov 19 03:31:24 2018
> @@ -0,0 +1,1164 @@
> +; RUN: opt -S -licm < %s | FileCheck %s
> +; RUN: opt -passes='require<opt-remark-emit>,loop(licm)' -S < %s |
> FileCheck %s
> +
> +; CHECK-LABEL: @triangle_phi
> +define void @triangle_phi(i32 %x, i32* %p) {
> +; CHECK-LABEL: entry:
> +; CHECK: %cmp1 = icmp sgt i32 %x, 0
> +; CHECK: br i1 %cmp1, label %[[IF_LICM:.*]], label %[[THEN_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: %add = add i32 %x, 1
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]:
> +; CHECK: phi i32 [ %add, %[[IF_LICM]] ], [ %x, %entry ]
> +; CHECK: store i32 %phi, i32* %p
> +; CHECK: %cmp2 = icmp ne i32 %phi, 0
> +; CHECK: br label %loop
> +
> +loop:
> + %cmp1 = icmp sgt i32 %x, 0
> + br i1 %cmp1, label %if, label %then
> +
> +if:
> + %add = add i32 %x, 1
> + br label %then
> +
> +then:
> + %phi = phi i32 [ %add, %if ], [ %x, %loop ]
> + store i32 %phi, i32* %p
> + %cmp2 = icmp ne i32 %phi, 0
> + br i1 %cmp2, label %loop, label %end
> +
> +end:
> + ret void
> +}
> +
> +; CHECK-LABEL: @diamond_phi
> +define void @diamond_phi(i32 %x, i32* %p) {
> +; CHECK-LABEL: entry:
> +; CHECK: %cmp1 = icmp sgt i32 %x, 0
> +; CHECK: br i1 %cmp1, label %[[IF_LICM:.*]], label %[[ELSE_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: %add = add i32 %x, 1
> +; CHECK: br label %[[THEN_LICM:.*]]
> +
> +; CHECK: [[ELSE_LICM]]:
> +; CHECK: %sub = sub i32 %x, 1
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]
> +; CHECK: %phi = phi i32 [ %add, %[[IF_LICM]] ], [ %sub, %[[ELSE_LICM]] ]
> +; CHECK: store i32 %phi, i32* %p
> +; CHECK: %cmp2 = icmp ne i32 %phi, 0
> +; CHECK: br label %loop
> +
> +loop:
> + %cmp1 = icmp sgt i32 %x, 0
> + br i1 %cmp1, label %if, label %else
> +
> +if:
> + %add = add i32 %x, 1
> + br label %then
> +
> +else:
> + %sub = sub i32 %x, 1
> + br label %then
> +
> +then:
> + %phi = phi i32 [ %add, %if ], [ %sub, %else ]
> + store i32 %phi, i32* %p
> + %cmp2 = icmp ne i32 %phi, 0
> + br i1 %cmp2, label %loop, label %end
> +
> +end:
> + ret void
> +}
> +
> +; TODO: This is currently too complicated for us to be able to hoist the
> phi.
> +; CHECK-LABEL: @three_way_phi
> +define void @three_way_phi(i32 %x, i32* %p) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %cmp1 = icmp sgt i32 %x, 0
> +; CHECK-DAG: %add = add i32 %x, 1
> +; CHECK-DAG: %cmp2 = icmp sgt i32 %add, 0
> +; CHECK: br i1 %cmp1, label %[[IF_LICM:.*]], label %[[ELSE_LICM:.*]]
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: br label %[[THEN_LICM:.*]]
> +
> +; CHECK: [[THEN_LICM]]:
> +; CHECK: %sub = sub i32 %x, 1
> +; CHECK: br label %loop
> +
> +entry:
> + br label %loop
> +
> +loop:
> + %cmp1 = icmp sgt i32 %x, 0
> + br i1 %cmp1, label %if, label %then
> +
> +if:
> + %add = add i32 %x, 1
> + %cmp2 = icmp sgt i32 %add, 0
> + br i1 %cmp2, label %if.if, label %then
> +
> +if.if:
> + %sub = sub i32 %x, 1
> + br label %then
> +
> +then:
> + %phi = phi i32 [ 0, %loop ], [ %add, %if ], [ %sub, %if.if ]
> + store i32 %phi, i32* %p
> + %cmp3 = icmp ne i32 %phi, 0
> + br i1 %cmp3, label %loop, label %end
> +
> +end:
> + ret void
> +}
> +
> +; TODO: This is currently too complicated for us to be able to hoist the
> phi.
> +; CHECK-LABEL: @tree_phi
> +define void @tree_phi(i32 %x, i32* %p) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %cmp1 = icmp sgt i32 %x, 0
> +; CHECK-DAG: %add = add i32 %x, 1
> +; CHECK-DAG: %cmp2 = icmp sgt i32 %add, 0
> +; CHECK-DAG: %sub = sub i32 %x, 1
> +; CHECK: br label %loop
> +
> +entry:
> + br label %loop
> +
> +loop:
> + %cmp1 = icmp sgt i32 %x, 0
> + br i1 %cmp1, label %if, label %else
> +
> +if:
> + %add = add i32 %x, 1
> + %cmp2 = icmp sgt i32 %add, 0
> + br i1 %cmp2, label %if.if, label %if.else
> +
> +if.if:
> + br label %then
> +
> +if.else:
> + br label %then
> +
> +else:
> + %sub = sub i32 %x, 1
> + br label %then
> +
> +then:
> + %phi = phi i32 [ %add, %if.if ], [ 0, %if.else ], [ %sub, %else ]
> + store i32 %phi, i32* %p
> + %cmp3 = icmp ne i32 %phi, 0
> + br i1 %cmp3, label %loop, label %end
> +
> +end:
> + ret void
> +}
> +
> +; TODO: We can hoist the first phi, but not the second.
> +; CHECK-LABEL: @phi_phi
> +define void @phi_phi(i32 %x, i32* %p) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %cmp1 = icmp sgt i32 %x, 0
> +; CHECK-DAG: %add = add i32 %x, 1
> +; CHECK-DAG: %cmp2 = icmp sgt i32 %add, 0
> +; CHECK-DAG: %sub = sub i32 %x, 1
> +; CHECK: br i1 %cmp2, label %[[IF_IF_LICM:.*]], label %[[IF_ELSE_LICM:.*]]
> +
> +; CHECK: [[IF_IF_LICM]]:
> +; CHECK: br label %[[IF_THEN_LICM:.*]]
> +
> +; CHECK: [[IF_ELSE_LICM]]:
> +; CHECK: br label %[[IF_THEN_LICM]]
> +
> +; CHECK: [[IF_THEN_LICM]]:
> +; CHECK: %phi1 = phi i32 [ %add, %[[IF_IF_LICM]] ], [ 0,
> %[[IF_ELSE_LICM]] ]
> +; CHECK: br label %loop
> +
> +entry:
> + br label %loop
> +
> +loop:
> + %cmp1 = icmp sgt i32 %x, 0
> + br i1 %cmp1, label %if, label %else
> +
> +if:
> + %add = add i32 %x, 1
> + %cmp2 = icmp sgt i32 %add, 0
> + br i1 %cmp2, label %if.if, label %if.else
> +
> +if.if:
> + br label %if.then
> +
> +if.else:
> + br label %if.then
> +
> +if.then:
> + %phi1 = phi i32 [ %add, %if.if ], [ 0, %if.else ]
> + br label %then
> +
> +else:
> + %sub = sub i32 %x, 1
> + br label %then
> +
> +then:
> + %phi2 = phi i32 [ %phi1, %if.then ], [ %sub, %else ]
> + store i32 %phi2, i32* %p
> + %cmp3 = icmp ne i32 %phi2, 0
> + br i1 %cmp3, label %loop, label %end
> +
> +end:
> + ret void
> +}
> +
> +; Check that we correctly duplicate empty control flow.
> +; CHECK-LABEL: @empty_triangle_phi
> +define i8 @empty_triangle_phi(i32 %x, i32 %y) {
> +; CHECK-LABEL: entry:
> +; CHECK: %cmp1 = icmp eq i32 %x, 0
> +; CHECK: br i1 %cmp1, label %[[IF_LICM:.*]], label %[[THEN_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]:
> +; CHECK: %phi = phi i8 [ 0, %[[IF_LICM]] ], [ 1, %entry ]
> +; CHECK: %cmp2 = icmp eq i32 %y, 0
> +; CHECK: br label %loop
> +
> +loop:
> + %cmp1 = icmp eq i32 %x, 0
> + br i1 %cmp1, label %if, label %then
> +
> +if:
> + br label %then
> +
> +then:
> + %phi = phi i8 [ 0, %if ], [ 1, %loop ]
> + %cmp2 = icmp eq i32 %y, 0
> + br i1 %cmp2, label %end, label %loop
> +
> +end:
> + ret i8 %phi
> +}
> +
> +; CHECK-LABEL: @empty_diamond_phi
> +define i8 @empty_diamond_phi(i32 %x, i32 %y) {
> +; CHECK-LABEL: entry:
> +; CHECK: %cmp1 = icmp eq i32 %x, 0
> +; CHECK: br i1 %cmp1, label %[[IF_LICM:.*]], label %[[ELSE_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: br label %[[THEN_LICM:.*]]
> +
> +; CHECK: [[ELSE_LICM]]:
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]:
> +; CHECK: %phi = phi i8 [ 0, %[[IF_LICM]] ], [ 1, %[[ELSE_LICM]] ]
> +; CHECK: %cmp2 = icmp eq i32 %y, 0
> +; CHECK: br label %loop
> +
> +loop:
> + %cmp1 = icmp eq i32 %x, 0
> + br i1 %cmp1, label %if, label %else
> +
> +if:
> + br label %then
> +
> +else:
> + br label %then
> +
> +then:
> + %phi = phi i8 [ 0, %if ], [ 1, %else ]
> + %cmp2 = icmp eq i32 %y, 0
> + br i1 %cmp2, label %end, label %loop
> +
> +end:
> + ret i8 %phi
> +}
> +
> +; Check that we correctly handle the case that the first thing we try to
> hoist is a phi.
> +; CHECK-LABEL: @empty_triangle_phi_first
> +define i8 @empty_triangle_phi_first(i32 %x, i1 %cond) {
> +; CHECK-LABEL: entry:
> +; CHECK: br i1 %cond, label %[[IF_LICM:.*]], label %[[THEN_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]:
> +; CHECK: %phi = phi i8 [ 0, %[[IF_LICM]] ], [ 1, %entry ]
> +; CHECK: %cmp = icmp eq i32 %x, 0
> +; CHECK: br label %loop
> +
> +loop:
> + br i1 %cond, label %if, label %then
> +
> +if:
> + br label %then
> +
> +then:
> + %phi = phi i8 [ 0, %if ], [ 1, %loop ]
> + %cmp = icmp eq i32 %x, 0
> + br i1 %cmp, label %end, label %loop
> +
> +end:
> + ret i8 %phi
> +}
> +
> +; CHECK-LABEL: @empty_diamond_phi
> +define i8 @empty_diamond_phi_first(i32 %x, i1 %cond) {
> +; CHECK-LABEL: entry:
> +; CHECK: br i1 %cond, label %[[IF_LICM:.*]], label %[[ELSE_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: br label %[[THEN_LICM:.*]]
> +
> +; CHECK: [[ELSE_LICM]]:
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]:
> +; CHECK: %phi = phi i8 [ 0, %[[IF_LICM]] ], [ 1, %[[ELSE_LICM]] ]
> +; CHECK: %cmp = icmp eq i32 %x, 0
> +; CHECK: br label %loop
> +
> +loop:
> + br i1 %cond, label %if, label %else
> +
> +if:
> + br label %then
> +
> +else:
> + br label %then
> +
> +then:
> + %phi = phi i8 [ 0, %if ], [ 1, %else ]
> + %cmp = icmp eq i32 %x, 0
> + br i1 %cmp, label %end, label %loop
> +
> +end:
> + ret i8 %phi
> +}
> +
> +; CHECK-LABEL: @empty_triangle_phi_first
> +define i8 @empty_triangle_phi_first_empty_loop_head(i32 %x, i1 %cond) {
> +; CHECK-LABEL: entry:
> +; CHECK: br i1 %cond, label %[[IF_LICM:.*]], label %[[THEN_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]:
> +; CHECK: %phi = phi i8 [ 0, %[[IF_LICM]] ], [ 1, %entry ]
> +; CHECK: %cmp = icmp eq i32 %x, 0
> +; CHECK: br label %loop
> +
> +loop:
> + br label %test
> +
> +test:
> + br i1 %cond, label %if, label %then
> +
> +if:
> + br label %then
> +
> +then:
> + %phi = phi i8 [ 0, %if ], [ 1, %test ]
> + %cmp = icmp eq i32 %x, 0
> + br i1 %cmp, label %end, label %loop
> +
> +end:
> + ret i8 %phi
> +}
> +
> +; CHECK-LABEL: @empty_diamond_phi_first_empty_loop_head
> +define i8 @empty_diamond_phi_first_empty_loop_head(i32 %x, i1 %cond) {
> +; CHECK-LABEL: entry:
> +; CHECK: br i1 %cond, label %[[IF_LICM:.*]], label %[[ELSE_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: br label %[[THEN_LICM:.*]]
> +
> +; CHECK: [[ELSE_LICM]]:
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]:
> +; CHECK: %phi = phi i8 [ 0, %[[IF_LICM]] ], [ 1, %[[ELSE_LICM]] ]
> +; CHECK: %cmp = icmp eq i32 %x, 0
> +; CHECK: br label %loop
> +
> +loop:
> + br label %test
> +
> +test:
> + br i1 %cond, label %if, label %else
> +
> +if:
> + br label %then
> +
> +else:
> + br label %then
> +
> +then:
> + %phi = phi i8 [ 0, %if ], [ 1, %else ]
> + %cmp = icmp eq i32 %x, 0
> + br i1 %cmp, label %end, label %loop
> +
> +end:
> + ret i8 %phi
> +}
> +
> +; The phi is on one branch of a diamond while simultaneously at the end
> of a
> +; triangle. Check that we duplicate the triangle and not the diamond.
> +; CHECK-LABEL: @triangle_diamond
> +define void @triangle_diamond(i32* %ptr, i32 %x, i32 %y) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %cmp1 = icmp ne i32 %x, 0
> +; CHECK-DAG: %cmp2 = icmp ne i32 %y, 0
> +; CHECK: br i1 %cmp1, label %[[IF_LICM:.*]], label %[[THEN_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]:
> +; CHECK: %phi = phi i32 [ 0, %[[IF_LICM]] ], [ 127, %entry ]
> +
> +loop:
> + %cmp1 = icmp ne i32 %x, 0
> + br i1 %cmp1, label %if, label %then
> +
> +if:
> + %cmp2 = icmp ne i32 %y, 0
> + br i1 %cmp2, label %if.then, label %then
> +
> +then:
> + %phi = phi i32 [ 0, %if ], [ 127, %loop ]
> + store i32 %phi, i32* %ptr
> + br label %end
> +
> +if.then:
> + br label %end
> +
> +end:
> + br label %loop
> +}
> +
> +; As the previous, but the end of the diamond is the head of the loop.
> +; CHECK-LABEL: @triangle_diamond_backedge
> +define void @triangle_diamond_backedge(i32* %ptr, i32 %x, i32 %y) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %cmp1 = icmp ne i32 %x, 0
> +; CHECK-DAG: %cmp2 = icmp ne i32 %y, 0
> +; CHECK: br i1 %cmp1, label %[[IF_LICM:.*]], label %[[THEN_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]:
> +; CHECK: %phi = phi i32 [ 0, %[[IF_LICM]] ], [ 127, %entry ]
> +
> +loop:
> + %cmp1 = icmp ne i32 %x, 0
> + br i1 %cmp1, label %if, label %then
> +
> +if:
> + %cmp2 = icmp ne i32 %y, 0
> + br i1 %cmp2, label %backedge, label %then
> +
> +then:
> + %phi = phi i32 [ 0, %if ], [ 127, %loop ]
> + store i32 %phi, i32* %ptr
> + br label %loop
> +
> +backedge:
> + br label %loop
> +}
> +
> +; TODO: The inner diamonds can be hoisted, but not currently the outer
> diamond
> +; CHECK-LABEL: @diamonds_inside_diamond
> +define void @diamonds_inside_diamond(i32 %x, i32* %p) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %cmp1 = icmp sgt i32 %x, 0
> +; CHECK-DAG: %cmp3 = icmp slt i32 %x, -10
> +; CHECK: br i1 %cmp3, label %[[ELSE_IF_LICM:.*]], label
> %[[ELSE_ELSE_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[ELSE_IF_LICM]]:
> +; CHECK: br label %[[ELSE_THEN_LICM:.*]]
> +
> +; CHECK: [[ELSE_ELSE_LICM]]:
> +; CHECK: br label %[[ELSE_THEN_LICM]]
> +
> +; CHECK: [[ELSE_THEN_LICM]]:
> +; CHECK: %phi2 = phi i32 [ 2, %[[ELSE_IF_LICM]] ], [ 3,
> %[[ELSE_ELSE_LICM]] ]
> +; CHECK: %cmp2 = icmp sgt i32 %x, 10
> +; CHECK: br i1 %cmp2, label %[[IF_IF_LICM:.*]], label %[[IF_ELSE_LICM:.*]]
> +
> +; CHECK: [[IF_IF_LICM]]:
> +; CHECK: br label %[[IF_THEN_LICM:.*]]
> +
> +; CHECK: [[IF_ELSE_LICM]]:
> +; CHECK: br label %[[IF_THEN_LICM]]
> +
> +; CHECK: [[IF_THEN_LICM]]:
> +; CHECK: %phi1 = phi i32 [ 0, %[[IF_IF_LICM]] ], [ 1, %[[IF_ELSE_LICM]] ]
> +; CHECK: br label %loop
> +
> +loop:
> + %cmp1 = icmp sgt i32 %x, 0
> + br i1 %cmp1, label %if, label %else
> +
> +if:
> + %cmp2 = icmp sgt i32 %x, 10
> + br i1 %cmp2, label %if.if, label %if.else
> +
> +if.if:
> + br label %if.then
> +
> +if.else:
> + br label %if.then
> +
> +if.then:
> + %phi1 = phi i32 [ 0, %if.if ], [ 1, %if.else ]
> + br label %then
> +
> +else:
> + %cmp3 = icmp slt i32 %x, -10
> + br i1 %cmp3, label %else.if, label %else.else
> +
> +else.if:
> + br label %else.then
> +
> +else.else:
> + br label %else.then
> +
> +else.then:
> + %phi2 = phi i32 [ 2, %else.if ], [ 3, %else.else ]
> + br label %then
> +
> +then:
> + %phi3 = phi i32 [ %phi1, %if.then ], [ %phi2, %else.then ]
> + store i32 %phi3, i32* %p
> + %cmp4 = icmp ne i32 %phi3, 0
> + br i1 %cmp4, label %loop, label %end
> +
> +end:
> + ret void
> +}
> +
> +; We can hoist blocks that contain an edge that exits the loop by
> ignoring that
> +; edge in the hoisted block.
> +; CHECK-LABEL: @triangle_phi_loopexit
> +define void @triangle_phi_loopexit(i32 %x, i32* %p) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %add = add i32 %x, 1
> +; CHECK-DAG: %cmp1 = icmp sgt i32 %x, 0
> +; CHECK-DAG: %cmp2 = icmp sgt i32 10, %add
> +; CHECK: br i1 %cmp1, label %[[IF_LICM:.*]], label %[[THEN_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]:
> +; CHECK: %phi = phi i32 [ %add, %[[IF_LICM]] ], [ %x, %entry ]
> +
> +loop:
> + %cmp1 = icmp sgt i32 %x, 0
> + br i1 %cmp1, label %if, label %then
> +
> +if:
> + %add = add i32 %x, 1
> + %cmp2 = icmp sgt i32 10, %add
> + br i1 %cmp2, label %then, label %end
> +
> +then:
> + %phi = phi i32 [ %add, %if ], [ %x, %loop ]
> + store i32 %phi, i32* %p
> + %cmp3 = icmp ne i32 %phi, 0
> + br i1 %cmp3, label %loop, label %end
> +
> +end:
> + ret void
> +}
> +
> +; CHECK-LABEL: @diamond_phi_oneloopexit
> +define void @diamond_phi_oneloopexit(i32 %x, i32* %p) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %add = add i32 %x, 1
> +; CHECK-DAG: %cmp1 = icmp sgt i32 %x, 0
> +; CHECK-DAG: %cmp2 = icmp sgt i32 10, %add
> +; CHECK: br i1 %cmp1, label %[[IF_LICM:.*]], label %[[THEN_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: br label %[[THEN_LICM:.*]]
> +
> +; CHECK: [[ELSE_LICM]]:
> +; CHECK: %sub = sub i32 %x, 1
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]
> +; CHECK: %phi = phi i32 [ %add, %[[IF_LICM]] ], [ %sub, %[[ELSE_LICM]] ]
> +; CHECK: %cmp3 = icmp ne i32 %phi, 0
> +; CHECK: br label %loop
> +
> +loop:
> + %cmp1 = icmp sgt i32 %x, 0
> + br i1 %cmp1, label %if, label %else
> +
> +if:
> + %add = add i32 %x, 1
> + %cmp2 = icmp sgt i32 10, %add
> + br i1 %cmp2, label %then, label %end
> +
> +else:
> + %sub = sub i32 %x, 1
> + br label %then
> +
> +then:
> + %phi = phi i32 [ %add, %if ], [ %sub, %else ]
> + store i32 %phi, i32* %p
> + %cmp3 = icmp ne i32 %phi, 0
> + br i1 %cmp3, label %loop, label %end
> +
> +end:
> + ret void
> +}
> +
> +; CHECK-LABEL: @diamond_phi_twoloopexit
> +define void @diamond_phi_twoloopexit(i32 %x, i32* %p) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %sub = sub i32 %x, 1
> +; CHECK-DAG: %add = add i32 %x, 1
> +; CHECK-DAG: %cmp1 = icmp sgt i32 %x, 0
> +; CHECK-DAG: %cmp2 = icmp sgt i32 10, %add
> +; CHECK-DAG: %cmp3 = icmp sgt i32 10, %sub
> +; CHECK: br i1 %cmp1, label %[[IF_LICM:.*]], label %[[THEN_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: br label %[[THEN_LICM:.*]]
> +
> +; CHECK: [[ELSE_LICM]]:
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]
> +; CHECK: %phi = phi i32 [ %add, %[[IF_LICM]] ], [ %sub, %[[ELSE_LICM]] ]
> +; CHECK: %cmp4 = icmp ne i32 %phi, 0
> +; CHECK: br label %loop
> +
> +loop:
> + %cmp1 = icmp sgt i32 %x, 0
> + br i1 %cmp1, label %if, label %else
> +
> +if:
> + %add = add i32 %x, 1
> + %cmp2 = icmp sgt i32 10, %add
> + br i1 %cmp2, label %then, label %end
> +
> +else:
> + %sub = sub i32 %x, 1
> + %cmp3 = icmp sgt i32 10, %sub
> + br i1 %cmp3, label %then, label %end
> +
> +then:
> + %phi = phi i32 [ %add, %if ], [ %sub, %else ]
> + store i32 %phi, i32* %p
> + %cmp4 = icmp ne i32 %phi, 0
> + br i1 %cmp4, label %loop, label %end
> +
> +end:
> + ret void
> +}
> +
> +; The store cannot be hoisted, so add and shr cannot be hoisted into a
> +; conditional block.
> +; CHECK-LABEL: @conditional_use
> +define void @conditional_use(i32 %x, i32* %p) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %cond = icmp ugt i32 %x, 0
> +; CHECK-DAG: %add = add i32 %x, 5
> +; CHECK-DAG: %shr = ashr i32 %add, 1
> +; CHECK: br label %loop
> +entry:
> + br label %loop
> +
> +loop:
> + %cond = icmp ugt i32 %x, 0
> + br i1 %cond, label %if, label %else
> +
> +; CHECK-LABEL: if:
> +; CHECK: store i32 %shr, i32* %p, align 4
> +if:
> + %add = add i32 %x, 5
> + %shr = ashr i32 %add, 1
> + store i32 %shr, i32* %p, align 4
> + br label %then
> +
> +else:
> + br label %then
> +
> +then:
> + br label %loop
> +}
> +
> +; A diamond with two triangles on the left and one on the right. This
> test is
> +; to check that we have a unique loop preheader when we hoist the store
> (and so
> +; don't fail an assertion).
> +; CHECK-LABEL: @triangles_in_diamond
> +define void @triangles_in_diamond(i32* %ptr) {
> +; CHECK-LABEL: entry:
> +; CHECK: store i32 0, i32* %ptr, align 4
> +; CHECK: br label %loop
> +entry:
> + br label %loop
> +
> +loop:
> + br i1 undef, label %left_triangle_1, label %right_triangle
> +
> +left_triangle_1:
> + br i1 undef, label %left_triangle_1_if, label %left_triangle_2
> +
> +left_triangle_1_if:
> + br label %left_triangle_2
> +
> +left_triangle_2:
> + br i1 undef, label %left_triangle_2_if, label %left_triangle_2_then
> +
> +left_triangle_2_if:
> + br label %left_triangle_2_then
> +
> +left_triangle_2_then:
> + br label %loop.end
> +
> +right_triangle:
> + br i1 undef, label %right_triangle.if, label %right_triangle.then
> +
> +right_triangle.if:
> + br label %right_triangle.then
> +
> +right_triangle.then:
> + br label %loop.end
> +
> +loop.end:
> + store i32 0, i32* %ptr, align 4
> + br label %loop
> +}
> +
> +; %cmp dominates its used after being hoisted, but not after %brmerge is
> rehoisted
> +; CHECK-LABEL: @rehoist
> +define void @rehoist(i8* %this, i32 %x) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %sub = add nsw i32 %x, -1
> +; CHECK-DAG: %fptr = bitcast i8* %this to void (i8*)*
> +; CHECK-DAG: %cmp = icmp eq i32 0, %sub
> +; CHECK-DAG: %brmerge = or i1 %cmp, true
> +entry:
> + %sub = add nsw i32 %x, -1
> + br label %loop
> +
> +loop:
> + br i1 undef, label %if1, label %else1
> +
> +if1:
> + %fptr = bitcast i8* %this to void (i8*)*
> + call void %fptr(i8* %this)
> + br label %then1
> +
> +else1:
> + br label %then1
> +
> +then1:
> + %cmp = icmp eq i32 0, %sub
> + br i1 %cmp, label %end, label %else2
> +
> +else2:
> + %brmerge = or i1 %cmp, true
> + br i1 %brmerge, label %if3, label %end
> +
> +if3:
> + br label %end
> +
> +end:
> + br label %loop
> +}
> +
> +; A test case that uses empty blocks in a way that can cause control flow
> +; hoisting to get confused.
> +; CHECK-LABEL: @empty_blocks_multiple_conditional_branches
> +define void @empty_blocks_multiple_conditional_branches(float %arg,
> float* %ptr) {
> +; CHECK-LABEL: entry
> +; CHECK-DAG: %div1 = fmul float %arg, 4.000000e+00
> +; CHECK-DAG: %div2 = fmul float %arg, 2.000000e+00
> +entry:
> + br label %loop
> +
> +; The exact path to the phi isn't checked here, because it depends on
> whether
> +; cond2 or cond3 is hoisted first
> +; CHECK: %phi = phi float [ 0.000000e+00, %{{.*}} ], [ %div1, %{{.*}} ]
> +; CHECK: br label %loop
> +
> +loop:
> + br i1 undef, label %backedge2, label %cond1
> +
> +cond1:
> + br i1 undef, label %cond1.if, label %cond1.else
> +
> +cond1.else:
> + br label %cond3
> +
> +cond1.if:
> + br label %cond1.if.next
> +
> +cond1.if.next:
> + br label %cond2
> +
> +cond2:
> + %div1 = fmul float %arg, 4.000000e+00
> + br i1 undef, label %cond2.if, label %cond2.then
> +
> +cond2.if:
> + br label %cond2.then
> +
> +cond2.then:
> + %phi = phi float [ 0.000000e+00, %cond2 ], [ %div1, %cond2.if ]
> + store float %phi, float* %ptr
> + br label %backedge2
> +
> +cond3:
> + br i1 undef, label %cond3.then, label %cond3.if
> +
> +cond3.if:
> + %div2 = fmul float %arg, 2.000000e+00
> + store float %div2, float* %ptr
> + br label %cond3.then
> +
> +cond3.then:
> + br label %loop
> +
> +backedge2:
> + br label %loop
> +}
> +
> +; We can't do much here, so mainly just check that we don't crash.
> +; CHECK-LABEL: @many_path_phi
> +define void @many_path_phi(i32* %ptr1, i32* %ptr2) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %gep3 = getelementptr inbounds i32, i32* %ptr2, i32 2
> +; CHECK-DAG: %gep2 = getelementptr inbounds i32, i32* %ptr2, i32 2
> +; CHECK: br label %loop
> +entry:
> + br label %loop
> +
> +loop:
> + %phi1 = phi i32 [ 0, %entry ], [ %phi2, %end ]
> + %cmp1 = icmp ugt i32 %phi1, 3
> + br i1 %cmp1, label %cond2, label %cond1
> +
> +cond1:
> + br i1 undef, label %end, label %cond1.else
> +
> +cond1.else:
> + %gep2 = getelementptr inbounds i32, i32* %ptr2, i32 2
> + %val2 = load i32, i32* %gep2, align 4
> + %cmp2 = icmp eq i32 %val2, 13
> + br i1 %cmp2, label %cond1.end, label %end
> +
> +cond1.end:
> + br label %end
> +
> +cond2:
> + br i1 undef, label %end, label %cond2.else
> +
> +cond2.else:
> + %gep3 = getelementptr inbounds i32, i32* %ptr2, i32 2
> + %val3 = load i32, i32* %gep3, align 4
> + %cmp3 = icmp eq i32 %val3, 13
> + br i1 %cmp3, label %cond2.end, label %end
> +
> +cond2.end:
> + br label %end
> +
> +end:
> + %phi2 = phi i32 [ 1, %cond1 ], [ 2, %cond1.else ], [ 3, %cond1.end ], [
> 4, %cond2 ], [ 5, %cond2.else ], [ 6, %cond2.end ]
> + br label %loop
> +}
> +
> +; Check that we correctly handle the hoisting of %gep when theres a
> critical
> +; edge that branches to the preheader.
> +; CHECK-LABEL: @crit_edge
> +define void @crit_edge(i32* %ptr, i32 %idx, i1 %cond1, i1 %cond2) {
> +; CHECK-LABEL: entry:
> +; CHECK: %gep = getelementptr inbounds i32, i32* %ptr, i32 %idx
> +; CHECK: br label %preheader
> +entry:
> + br label %preheader
> +
> +preheader:
> + br label %loop
> +
> +loop:
> + br i1 %cond1, label %then, label %if
> +
> +if:
> + %gep = getelementptr inbounds i32, i32* %ptr, i32 %idx
> + %val = load i32, i32* %gep
> + br label %then
> +
> +then:
> + %phi = phi i32 [ %val, %if ], [ 0, %loop ]
> + store i32 %phi, i32* %ptr
> + br i1 %cond2, label %loop, label %crit_edge
> +
> +crit_edge:
> + br label %preheader
> +}
> +
> +; Check that the conditional sub is correctly hoisted from the inner loop
> to the
> +; preheader of the outer loop.
> +; CHECK-LABEL: @hoist_from_innermost_loop
> +define void @hoist_from_innermost_loop(i32 %nx, i32* %ptr) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %sub = sub nsw i32 0, %nx
> +; CHECK: br label %outer_loop
> +entry:
> + br label %outer_loop
> +
> +outer_loop:
> + br label %middle_loop
> +
> +middle_loop:
> + br label %inner_loop
> +
> +inner_loop:
> + br i1 undef, label %inner_loop_end, label %if
> +
> +if:
> + %sub = sub nsw i32 0, %nx
> + store i32 %sub, i32* %ptr, align 4
> + br label %inner_loop_end
> +
> +inner_loop_end:
> + br i1 undef, label %inner_loop, label %middle_loop_end
> +
> +middle_loop_end:
> + br i1 undef, label %middle_loop, label %outer_loop_end
> +
> +outer_loop_end:
> + br label %outer_loop
> +}
> +
> +; We have a diamond starting from %if, but %if.if is also reachable from
> %loop,
> +; so %gep should not be conditionally hoisted.
> +; CHECK-LABEL: @diamond_with_extra_in_edge
> +define void @diamond_with_extra_in_edge(i32* %ptr1, i32* %ptr2, i32 %arg)
> {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %cmp2 = icmp ne i32 0, %arg
> +; CHECK-DAG: %gep = getelementptr i32, i32* %ptr1, i32 4
> +; CHECK: br label %loop
> +entry:
> + br label %loop
> +
> +loop:
> + %phi1 = phi i32 [ 0, %entry ], [ %phi2, %then ]
> + %cmp1 = icmp ugt i32 16, %phi1
> + br i1 %cmp1, label %if, label %if.if
> +
> +if:
> + %cmp2 = icmp ne i32 0, %arg
> + br i1 %cmp2, label %if.if, label %if.else
> +
> +if.if:
> + %gep = getelementptr i32, i32* %ptr1, i32 4
> + %val = load i32, i32* %gep, align 4
> + br label %then
> +
> +if.else:
> + br label %then
> +
> +then:
> + %phi2 = phi i32 [ %val, %if.if ], [ %phi1, %if.else ]
> + store i32 %phi2, i32* %ptr2, align 4
> + br label %loop
> +}
> +
> +; %loop/%if/%then form a triangle, but %loop/%if/%then/%end also form a
> diamond.
> +; The triangle should be picked for conditional hoisting.
> +; CHECK-LABEL: @both_triangle_and_diamond
> +define void @both_triangle_and_diamond(i32* %ptr1, i32* %ptr2, i32 %arg) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %cmp1 = icmp ne i32 0, %arg
> +; CHECK-DAG: %gep = getelementptr i32, i32* %ptr1, i32 4
> +; CHECK: br i1 %cmp1, label %[[IF_LICM:.*]], label %[[THEN_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[IF_LICM]]:
> +; CHECK: br label %[[THEN_LICM]]
> +
> +; CHECK: [[THEN_LICM]]:
> +; CHECK: %phi2 = phi i32 [ 0, %[[IF_LICM]] ], [ 1, %entry ]
> +; CHECK: br label %loop
> +
> +loop:
> + %phi1 = phi i32 [ 0, %entry ], [ %phi3, %end ]
> + %cmp1 = icmp ne i32 0, %arg
> + br i1 %cmp1, label %if, label %then
> +
> +if:
> + %gep = getelementptr i32, i32* %ptr1, i32 4
> + %val = load i32, i32* %gep, align 4
> + %cmp2 = icmp ugt i32 16, %phi1
> + br i1 %cmp2, label %end, label %then
> +
> +then:
> + %phi2 = phi i32 [ 0, %if ], [ 1, %loop ]
> + br label %end
> +
> +end:
> + %phi3 = phi i32 [ %phi2, %then ], [ %val, %if ]
> + store i32 %phi3, i32* %ptr2, align 4
> + br label %loop
> +}
> +
> +; We shouldn't duplicate the branch at the end of %loop and should
> instead hoist
> +; %val to %entry.
> +; CHECK-LABEL: @same_destination_branch
> +define i32 @same_destination_branch(i32 %arg1, i32 %arg2) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %cmp1 = icmp ne i32 %arg2, 0
> +; CHECK-DAG: %val = add i32 %arg1, 1
> +; CHECK: br label %loop
> +entry:
> + br label %loop
> +
> +loop:
> + %phi = phi i32 [ 0, %entry ], [ %add, %then ]
> + %add = add i32 %phi, 1
> + %cmp1 = icmp ne i32 %arg2, 0
> + br i1 %cmp1, label %if, label %if
> +
> +if:
> + %val = add i32 %arg1, 1
> + br label %then
> +
> +then:
> + %cmp2 = icmp ne i32 %val, %phi
> + br i1 %cmp2, label %loop, label %end
> +
> +end:
> + ret i32 %val
> +}
> +
> +; Diamond-like control flow but the left/right blocks actually have the
> same
> +; destinations.
> +; TODO: We could potentially hoist all of phi2-4, but currently only
> hoist phi2.
> +; CHECK-LABEL: @diamond_like_same_destinations
> +define i32 @diamond_like_same_destinations(i32 %arg1, i32 %arg2) {
> +; CHECK-LABEL: entry:
> +; CHECK-DAG: %cmp1 = icmp ne i32 %arg1, 0
> +; CHECK-DAG: %cmp2 = icmp ugt i32 %arg2, 1
> +; CHECK-DAG: %cmp3 = icmp ugt i32 %arg2, 2
> +; CHECK: br i1 %cmp1, label %[[LEFT1_LICM:.*]], label %[[RIGHT1_LICM:.*]]
> +entry:
> + br label %loop
> +
> +; CHECK: [[LEFT1_LICM]]:
> +; CHECK: br label %[[LEFT2_LICM:.*]]
> +
> +; CHECK: [[RIGHT1_LICM]]:
> +; CHECK: br label %[[LEFT2_LICM]]
> +
> +; CHECK: [[LEFT2_LICM]]:
> +; CHECK: %phi2 = phi i32 [ 0, %[[LEFT1_LICM]] ], [ 1, %[[RIGHT1_LICM]] ]
> +; CHECK: br label %loop
> +
> +loop:
> + %phi1 = phi i32 [ 0, %entry ], [ %add, %loopend ]
> + %add = add i32 %phi1, 1
> + %cmp1 = icmp ne i32 %arg1, 0
> + br i1 %cmp1, label %left1, label %right1
> +
> +left1:
> + %cmp2 = icmp ugt i32 %arg2, 1
> + br i1 %cmp2, label %left2, label %right2
> +
> +right1:
> + %cmp3 = icmp ugt i32 %arg2, 2
> + br i1 %cmp3, label %left2, label %right2
> +
> +left2:
> + %phi2 = phi i32 [ 0, %left1 ], [ 1, %right1 ]
> + br label %loopend
> +
> +right2:
> + %phi3 = phi i32 [ 2, %left1 ], [ 3, %right1 ]
> + br label %loopend
> +
> +loopend:
> + %phi4 = phi i32 [ %phi2, %left2 ], [ %phi3, %right2 ]
> + %cmp4 = icmp ne i32 %phi1, 32
> + br i1 %cmp4, label %loop, label %end
> +
> +end:
> + ret i32 %phi4
> +}
> +
> +; A phi with multiple incoming values for the same block due to a branch
> with
> +; two destinations that are actually the same. We can't hoist this.
> +; TODO: This could be hoisted by erasing one of the incoming values.
> +; CHECK-LABEL: @phi_multiple_values_same_block
> +define i32 @phi_multiple_values_same_block(i32 %arg) {
> +; CHECK-LABEL: entry:
> +; CHECK: %cmp = icmp sgt i32 %arg, 4
> +; CHECK-NOT: phi
> +; CHECK: br label %loop
> +entry:
> + br label %loop
> +
> +loop:
> + %cmp = icmp sgt i32 %arg, 4
> + br i1 %cmp, label %if, label %then
> +
> +if:
> + br i1 undef, label %then, label %then
> +
> +then:
> + %phi = phi i32 [ %arg, %loop ], [ 1, %if ], [ 1, %if ]
> + br i1 undef, label %exit, label %loop
> +
> +exit:
> + ret i32 %phi
> +}
>
> Modified:
> llvm/trunk/test/Transforms/LoopVectorize/invariant-store-vectorization.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/invariant-store-vectorization.ll?rev=347190&r1=347189&r2=347190&view=diff
>
> ==============================================================================
> ---
> llvm/trunk/test/Transforms/LoopVectorize/invariant-store-vectorization.ll
> (original)
> +++
> llvm/trunk/test/Transforms/LoopVectorize/invariant-store-vectorization.ll
> Mon Nov 19 03:31:24 2018
> @@ -266,19 +266,26 @@ for.end:
> ; variant/invariant values being stored to invariant address.
> ; test checks that the last element of the phi is extracted and scalar
> stored
> ; into the uniform address within the loop.
> -; Since the condition and the phi is loop invariant, they are LICM'ed
> after
> +; Since the condition and the phi is loop invariant, they are LICM'ed
> before
> ; vectorization.
> ; CHECK-LABEL: inv_val_store_to_inv_address_conditional_inv
> ; CHECK-NEXT: entry:
> +; CHECK-NEXT: [[B1:%.*]] = bitcast i32* [[B:%.*]] to i8*
> +; CHECK-NEXT: [[A4:%.*]] = bitcast i32* [[A:%.*]] to i8*
> ; CHECK-NEXT: [[NTRUNC:%.*]] = trunc i64 [[N:%.*]] to i32
> ; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[NTRUNC]], [[K:%.*]]
> +; CHECK-NEXT: br i1 [[CMP]], label %[[COND_STORE_LICM:.*]], label
> %[[COND_STORE_K_LICM:.*]]
> +; CHECK: [[COND_STORE_LICM]]:
> +; CHECK-NEXT: br label %[[LATCH_LICM:.*]]
> +; CHECK: [[COND_STORE_K_LICM]]:
> +; CHECK-NEXT: br label %[[LATCH_LICM]]
> +; CHECK: [[LATCH_LICM]]:
> +; CHECK-NEXT: [[STOREVAL:%.*]] = phi i32 [ [[NTRUNC]],
> %[[COND_STORE_LICM]] ], [ [[K]], %[[COND_STORE_K_LICM]] ]
> ; CHECK-NEXT: [[TMP0:%.*]] = icmp sgt i64 [[N]], 1
> ; CHECK-NEXT: [[SMAX:%.*]] = select i1 [[TMP0]], i64 [[N]], i64 1
> ; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[SMAX]], 4
> ; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]],
> label [[VECTOR_MEMCHECK:%.*]]
> ; CHECK: vector.memcheck:
> -; CHECK-NEXT: [[A4:%.*]] = bitcast i32* [[A:%.*]] to i8*
> -; CHECK-NEXT: [[B1:%.*]] = bitcast i32* [[B:%.*]] to i8*
> ; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i64 [[N]], 1
> ; CHECK-NEXT: [[SMAX2:%.*]] = select i1 [[TMP1]], i64 [[N]], i64 1
> ; CHECK-NEXT: [[SCEVGEP:%.*]] = getelementptr i32, i32* [[B]], i64
> [[SMAX2]]
> @@ -291,17 +298,13 @@ for.end:
> ; CHECK-NEXT: [[N_VEC:%.*]] = and i64 [[SMAX]], 9223372036854775804
> ; CHECK-NEXT: [[BROADCAST_SPLATINSERT5:%.*]] = insertelement <4 x i32>
> undef, i32 [[NTRUNC]], i32 0
> ; CHECK-NEXT: [[BROADCAST_SPLAT6:%.*]] = shufflevector <4 x i32>
> [[BROADCAST_SPLATINSERT5]], <4 x i32> undef, <4 x i32> zeroinitializer
> -; CHECK-NEXT: [[TMP2:%.*]] = insertelement <4 x i1> undef, i1 [[CMP]],
> i32 3
> -; CHECK-NEXT: [[TMP3:%.*]] = insertelement <4 x i32> undef, i32 [[K]],
> i32 3
> -; CHECK-NEXT: [[PREDPHI:%.*]] = select <4 x i1> [[TMP2]], <4 x i32>
> [[BROADCAST_SPLAT6]], <4 x i32> [[TMP3]]
> -; CHECK-NEXT: [[TMP5:%.*]] = extractelement <4 x i32> [[PREDPHI]], i32
> 3
> ; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
> ; CHECK: vector.body:
> ; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [
> [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
> ; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i32, i32* [[B]],
> i64 [[INDEX]]
> ; CHECK-NEXT: [[TMP7:%.*]] = bitcast i32* [[TMP6]] to <4 x i32>*
> ; CHECK-NEXT: store <4 x i32> [[BROADCAST_SPLAT6]], <4 x i32>*
> [[TMP7]], align 4
> -; CHECK-NEXT: store i32 [[TMP5]], i32* [[A]], align 4
> +; CHECK-NEXT: store i32 [[STOREVAL]], i32* [[A]], align 4
> ; CHECK-NEXT: [[INDEX_NEXT]] = add i64 [[INDEX]], 4
> ; CHECK-NEXT: [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
> ; CHECK-NEXT: br i1 [[TMP8]], label [[MIDDLE_BLOCK:%.*]], label
> [[VECTOR_BODY]]
> @@ -321,7 +324,6 @@ for.end:
> ; CHECK: cond_store_k:
> ; CHECK-NEXT: br label [[LATCH]]
> ; CHECK: latch:
> -; CHECK-NEXT: [[STOREVAL:%.*]] = phi i32 [ [[NTRUNC]], [[COND_STORE]]
> ], [ [[K]], [[COND_STORE_K]] ]
> ; CHECK-NEXT: store i32 [[STOREVAL]], i32* [[A]], align 4
> ; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1
> ; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
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