[llvm] r265388 - Adds the ability to use an epilog remainder loop during loop unrolling and makes
Michael Zolotukhin via llvm-commits
llvm-commits at lists.llvm.org
Fri Apr 8 13:23:31 PDT 2016
Hi Evgeny,
We’ve found several performance regressions on LLVM testsuite caused by this patch. Do you have a data from your performance experiments to back-up the decision to make epilogues the default strategy?
One of the biggest regressions we see is 89% on SingleSource/Benchmarks/Stanford/Bubblesort (on x86), while the biggest gain is only 30%.
Thanks,
Michael
> On Apr 5, 2016, at 5:19 AM, David L Kreitzer via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>
> Author: dlkreitz
> Date: Tue Apr 5 07:19:35 2016
> New Revision: 265388
>
> URL: http://llvm.org/viewvc/llvm-project?rev=265388&view=rev
> Log:
> Adds the ability to use an epilog remainder loop during loop unrolling and makes
> this the default behavior.
>
> Patch by Evgeny Stupachenko (evstupac at gmail.com).
>
> Differential Revision: http://reviews.llvm.org/D18158
>
> Modified:
> llvm/trunk/include/llvm/Transforms/Utils/UnrollLoop.h
> llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp
> llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp
> llvm/trunk/test/Transforms/LoopUnroll/AArch64/runtime-loop.ll
> llvm/trunk/test/Transforms/LoopUnroll/PowerPC/a2-unrolling.ll
> llvm/trunk/test/Transforms/LoopUnroll/X86/mmx.ll
> llvm/trunk/test/Transforms/LoopUnroll/high-cost-trip-count-computation.ll
> llvm/trunk/test/Transforms/LoopUnroll/runtime-loop.ll
> llvm/trunk/test/Transforms/LoopUnroll/runtime-loop1.ll
> llvm/trunk/test/Transforms/LoopUnroll/runtime-loop2.ll
> llvm/trunk/test/Transforms/LoopUnroll/runtime-loop4.ll
> llvm/trunk/test/Transforms/LoopUnroll/runtime-loop5.ll
> llvm/trunk/test/Transforms/LoopUnroll/tripcount-overflow.ll
> llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll
> llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll
>
> Modified: llvm/trunk/include/llvm/Transforms/Utils/UnrollLoop.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/UnrollLoop.h?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/Transforms/Utils/UnrollLoop.h (original)
> +++ llvm/trunk/include/llvm/Transforms/Utils/UnrollLoop.h Tue Apr 5 07:19:35 2016
> @@ -34,10 +34,11 @@ bool UnrollLoop(Loop *L, unsigned Count,
> LoopInfo *LI, ScalarEvolution *SE, DominatorTree *DT,
> AssumptionCache *AC, bool PreserveLCSSA);
>
> -bool UnrollRuntimeLoopProlog(Loop *L, unsigned Count,
> - bool AllowExpensiveTripCount, LoopInfo *LI,
> - ScalarEvolution *SE, DominatorTree *DT,
> - bool PreserveLCSSA);
> +bool UnrollRuntimeLoopRemainder(Loop *L, unsigned Count,
> + bool AllowExpensiveTripCount,
> + bool UseEpilogRemainder, LoopInfo *LI,
> + ScalarEvolution *SE, DominatorTree *DT,
> + bool PreserveLCSSA);
>
> MDNode *GetUnrollMetadata(MDNode *LoopID, StringRef Name);
> }
>
> Modified: llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp (original)
> +++ llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp Tue Apr 5 07:19:35 2016
> @@ -44,6 +44,11 @@ using namespace llvm;
> STATISTIC(NumCompletelyUnrolled, "Number of loops completely unrolled");
> STATISTIC(NumUnrolled, "Number of loops unrolled (completely or otherwise)");
>
> +static cl::opt<bool>
> +UnrollRuntimeEpilog("unroll-runtime-epilog", cl::init(true), cl::Hidden,
> + cl::desc("Allow runtime unrolled loops to be unrolled "
> + "with epilog instead of prolog."));
> +
> /// Convert the instruction operands from referencing the current values into
> /// those specified by VMap.
> static inline void remapInstruction(Instruction *I,
> @@ -288,12 +293,13 @@ bool llvm::UnrollLoop(Loop *L, unsigned
> "convergent "
> "operation.");
> });
> - // Don't output the runtime loop prolog if Count is a multiple of
> - // TripMultiple. Such a prolog is never needed, and is unsafe if the loop
> + // Don't output the runtime loop remainder if Count is a multiple of
> + // TripMultiple. Such a remainder is never needed, and is unsafe if the loop
> // contains a convergent instruction.
> if (RuntimeTripCount && TripMultiple % Count != 0 &&
> - !UnrollRuntimeLoopProlog(L, Count, AllowExpensiveTripCount, LI, SE, DT,
> - PreserveLCSSA))
> + !UnrollRuntimeLoopRemainder(L, Count, AllowExpensiveTripCount,
> + UnrollRuntimeEpilog, LI, SE, DT,
> + PreserveLCSSA))
> return false;
>
> // Notify ScalarEvolution that the loop will be substantially changed,
>
> Modified: llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp (original)
> +++ llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp Tue Apr 5 07:19:35 2016
> @@ -16,8 +16,8 @@
> // case, we need to generate code to execute these 'left over' iterations.
> //
> // The current strategy generates an if-then-else sequence prior to the
> -// unrolled loop to execute the 'left over' iterations. Other strategies
> -// include generate a loop before or after the unrolled loop.
> +// unrolled loop to execute the 'left over' iterations before or after the
> +// unrolled loop.
> //
> //===----------------------------------------------------------------------===//
>
> @@ -60,33 +60,35 @@ STATISTIC(NumRuntimeUnrolled,
> /// than the unroll factor.
> ///
> static void ConnectProlog(Loop *L, Value *BECount, unsigned Count,
> - BasicBlock *LastPrologBB, BasicBlock *PrologEnd,
> - BasicBlock *OrigPH, BasicBlock *NewPH,
> - ValueToValueMapTy &VMap, DominatorTree *DT,
> - LoopInfo *LI, bool PreserveLCSSA) {
> + BasicBlock *PrologExit, BasicBlock *PreHeader,
> + BasicBlock *NewPreHeader, ValueToValueMapTy &VMap,
> + DominatorTree *DT, LoopInfo *LI, bool PreserveLCSSA) {
> BasicBlock *Latch = L->getLoopLatch();
> assert(Latch && "Loop must have a latch");
> + BasicBlock *PrologLatch = cast<BasicBlock>(VMap[Latch]);
>
> // Create a PHI node for each outgoing value from the original loop
> // (which means it is an outgoing value from the prolog code too).
> // The new PHI node is inserted in the prolog end basic block.
> - // The new PHI name is added as an operand of a PHI node in either
> + // The new PHI node value is added as an operand of a PHI node in either
> // the loop header or the loop exit block.
> - for (succ_iterator SBI = succ_begin(Latch), SBE = succ_end(Latch);
> - SBI != SBE; ++SBI) {
> - for (BasicBlock::iterator BBI = (*SBI)->begin();
> - PHINode *PN = dyn_cast<PHINode>(BBI); ++BBI) {
> -
> + for (BasicBlock *Succ : successors(Latch)) {
> + for (Instruction &BBI : *Succ) {
> + PHINode *PN = dyn_cast<PHINode>(&BBI);
> + // Exit when we passed all PHI nodes.
> + if (!PN)
> + break;
> // Add a new PHI node to the prolog end block and add the
> // appropriate incoming values.
> - PHINode *NewPN = PHINode::Create(PN->getType(), 2, PN->getName()+".unr",
> - PrologEnd->getTerminator());
> + PHINode *NewPN = PHINode::Create(PN->getType(), 2, PN->getName() + ".unr",
> + PrologExit->getFirstNonPHI());
> // Adding a value to the new PHI node from the original loop preheader.
> // This is the value that skips all the prolog code.
> if (L->contains(PN)) {
> - NewPN->addIncoming(PN->getIncomingValueForBlock(NewPH), OrigPH);
> + NewPN->addIncoming(PN->getIncomingValueForBlock(NewPreHeader),
> + PreHeader);
> } else {
> - NewPN->addIncoming(UndefValue::get(PN->getType()), OrigPH);
> + NewPN->addIncoming(UndefValue::get(PN->getType()), PreHeader);
> }
>
> Value *V = PN->getIncomingValueForBlock(Latch);
> @@ -97,22 +99,22 @@ static void ConnectProlog(Loop *L, Value
> }
> // Adding a value to the new PHI node from the last prolog block
> // that was created.
> - NewPN->addIncoming(V, LastPrologBB);
> + NewPN->addIncoming(V, PrologLatch);
>
> // Update the existing PHI node operand with the value from the
> // new PHI node. How this is done depends on if the existing
> // PHI node is in the original loop block, or the exit block.
> if (L->contains(PN)) {
> - PN->setIncomingValue(PN->getBasicBlockIndex(NewPH), NewPN);
> + PN->setIncomingValue(PN->getBasicBlockIndex(NewPreHeader), NewPN);
> } else {
> - PN->addIncoming(NewPN, PrologEnd);
> + PN->addIncoming(NewPN, PrologExit);
> }
> }
> }
>
> // Create a branch around the original loop, which is taken if there are no
> // iterations remaining to be executed after running the prologue.
> - Instruction *InsertPt = PrologEnd->getTerminator();
> + Instruction *InsertPt = PrologExit->getTerminator();
> IRBuilder<> B(InsertPt);
>
> assert(Count != 0 && "nonsensical Count!");
> @@ -126,25 +128,152 @@ static void ConnectProlog(Loop *L, Value
> BasicBlock *Exit = L->getUniqueExitBlock();
> assert(Exit && "Loop must have a single exit block only");
> // Split the exit to maintain loop canonicalization guarantees
> - SmallVector<BasicBlock*, 4> Preds(pred_begin(Exit), pred_end(Exit));
> + SmallVector<BasicBlock*, 4> Preds(predecessors(Exit));
> SplitBlockPredecessors(Exit, Preds, ".unr-lcssa", DT, LI,
> PreserveLCSSA);
> // Add the branch to the exit block (around the unrolled loop)
> - B.CreateCondBr(BrLoopExit, Exit, NewPH);
> + B.CreateCondBr(BrLoopExit, Exit, NewPreHeader);
> + InsertPt->eraseFromParent();
> +}
> +
> +/// Connect the unrolling epilog code to the original loop.
> +/// The unrolling epilog code contains code to execute the
> +/// 'extra' iterations if the run-time trip count modulo the
> +/// unroll count is non-zero.
> +///
> +/// This function performs the following:
> +/// - Update PHI nodes at the unrolling loop exit and epilog loop exit
> +/// - Create PHI nodes at the unrolling loop exit to combine
> +/// values that exit the unrolling loop code and jump around it.
> +/// - Update PHI operands in the epilog loop by the new PHI nodes
> +/// - Branch around the epilog loop if extra iters (ModVal) is zero.
> +///
> +static void ConnectEpilog(Loop *L, Value *ModVal, BasicBlock *NewExit,
> + BasicBlock *Exit, BasicBlock *PreHeader,
> + BasicBlock *EpilogPreHeader, BasicBlock *NewPreHeader,
> + ValueToValueMapTy &VMap, DominatorTree *DT,
> + LoopInfo *LI, bool PreserveLCSSA) {
> + BasicBlock *Latch = L->getLoopLatch();
> + assert(Latch && "Loop must have a latch");
> + BasicBlock *EpilogLatch = cast<BasicBlock>(VMap[Latch]);
> +
> + // Loop structure should be the following:
> + //
> + // PreHeader
> + // NewPreHeader
> + // Header
> + // ...
> + // Latch
> + // NewExit (PN)
> + // EpilogPreHeader
> + // EpilogHeader
> + // ...
> + // EpilogLatch
> + // Exit (EpilogPN)
> +
> + // Update PHI nodes at NewExit and Exit.
> + for (Instruction &BBI : *NewExit) {
> + PHINode *PN = dyn_cast<PHINode>(&BBI);
> + // Exit when we passed all PHI nodes.
> + if (!PN)
> + break;
> + // PN should be used in another PHI located in Exit block as
> + // Exit was split by SplitBlockPredecessors into Exit and NewExit
> + // Basicaly it should look like:
> + // NewExit:
> + // PN = PHI [I, Latch]
> + // ...
> + // Exit:
> + // EpilogPN = PHI [PN, EpilogPreHeader]
> + //
> + // There is EpilogPreHeader incoming block instead of NewExit as
> + // NewExit was spilt 1 more time to get EpilogPreHeader.
> + assert(PN->hasOneUse() && "The phi should have 1 use");
> + PHINode *EpilogPN = cast<PHINode> (PN->use_begin()->getUser());
> + assert(EpilogPN->getParent() == Exit && "EpilogPN should be in Exit block");
> +
> + // Add incoming PreHeader from branch around the Loop
> + PN->addIncoming(UndefValue::get(PN->getType()), PreHeader);
> +
> + Value *V = PN->getIncomingValueForBlock(Latch);
> + Instruction *I = dyn_cast<Instruction>(V);
> + if (I && L->contains(I))
> + // If value comes from an instruction in the loop add VMap value.
> + V = VMap[I];
> + // For the instruction out of the loop, constant or undefined value
> + // insert value itself.
> + EpilogPN->addIncoming(V, EpilogLatch);
> +
> + assert(EpilogPN->getBasicBlockIndex(EpilogPreHeader) >= 0 &&
> + "EpilogPN should have EpilogPreHeader incoming block");
> + // Change EpilogPreHeader incoming block to NewExit.
> + EpilogPN->setIncomingBlock(EpilogPN->getBasicBlockIndex(EpilogPreHeader),
> + NewExit);
> + // Now PHIs should look like:
> + // NewExit:
> + // PN = PHI [I, Latch], [undef, PreHeader]
> + // ...
> + // Exit:
> + // EpilogPN = PHI [PN, NewExit], [VMap[I], EpilogLatch]
> + }
> +
> + // Create PHI nodes at NewExit (from the unrolling loop Latch and PreHeader).
> + // Update corresponding PHI nodes in epilog loop.
> + for (BasicBlock *Succ : successors(Latch)) {
> + // Skip this as we already updated phis in exit blocks.
> + if (!L->contains(Succ))
> + continue;
> + for (Instruction &BBI : *Succ) {
> + PHINode *PN = dyn_cast<PHINode>(&BBI);
> + // Exit when we passed all PHI nodes.
> + if (!PN)
> + break;
> + // Add new PHI nodes to the loop exit block and update epilog
> + // PHIs with the new PHI values.
> + PHINode *NewPN = PHINode::Create(PN->getType(), 2, PN->getName() + ".unr",
> + NewExit->getFirstNonPHI());
> + // Adding a value to the new PHI node from the unrolling loop preheader.
> + NewPN->addIncoming(PN->getIncomingValueForBlock(NewPreHeader), PreHeader);
> + // Adding a value to the new PHI node from the unrolling loop latch.
> + NewPN->addIncoming(PN->getIncomingValueForBlock(Latch), Latch);
> +
> + // Update the existing PHI node operand with the value from the new PHI
> + // node. Corresponding instruction in epilog loop should be PHI.
> + PHINode *VPN = cast<PHINode>(VMap[&BBI]);
> + VPN->setIncomingValue(VPN->getBasicBlockIndex(EpilogPreHeader), NewPN);
> + }
> + }
> +
> + Instruction *InsertPt = NewExit->getTerminator();
> + IRBuilder<> B(InsertPt);
> + Value *BrLoopExit = B.CreateIsNotNull(ModVal);
> + assert(Exit && "Loop must have a single exit block only");
> + // Split the exit to maintain loop canonicalization guarantees
> + SmallVector<BasicBlock*, 4> Preds(predecessors(Exit));
> + SplitBlockPredecessors(Exit, Preds, ".epilog-lcssa", DT, LI,
> + PreserveLCSSA);
> + // Add the branch to the exit block (around the unrolling loop)
> + B.CreateCondBr(BrLoopExit, EpilogPreHeader, Exit);
> InsertPt->eraseFromParent();
> }
>
> /// Create a clone of the blocks in a loop and connect them together.
> -/// If UnrollProlog is true, loop structure will not be cloned, otherwise a new
> -/// loop will be created including all cloned blocks, and the iterator of it
> -/// switches to count NewIter down to 0.
> +/// If CreateRemainderLoop is false, loop structure will not be cloned,
> +/// otherwise a new loop will be created including all cloned blocks, and the
> +/// iterator of it switches to count NewIter down to 0.
> +/// The cloned blocks should be inserted between InsertTop and InsertBot.
> +/// If loop structure is cloned InsertTop should be new preheader, InsertBot
> +/// new loop exit.
> ///
> -static void CloneLoopBlocks(Loop *L, Value *NewIter, const bool UnrollProlog,
> +static void CloneLoopBlocks(Loop *L, Value *NewIter,
> + const bool CreateRemainderLoop,
> + const bool UseEpilogRemainder,
> BasicBlock *InsertTop, BasicBlock *InsertBot,
> + BasicBlock *Preheader,
> std::vector<BasicBlock *> &NewBlocks,
> LoopBlocksDFS &LoopBlocks, ValueToValueMapTy &VMap,
> LoopInfo *LI) {
> - BasicBlock *Preheader = L->getLoopPreheader();
> + StringRef suffix = UseEpilogRemainder ? "epil" : "prol";
> BasicBlock *Header = L->getHeader();
> BasicBlock *Latch = L->getLoopLatch();
> Function *F = Header->getParent();
> @@ -152,7 +281,7 @@ static void CloneLoopBlocks(Loop *L, Val
> LoopBlocksDFS::RPOIterator BlockEnd = LoopBlocks.endRPO();
> Loop *NewLoop = nullptr;
> Loop *ParentLoop = L->getParentLoop();
> - if (!UnrollProlog) {
> + if (CreateRemainderLoop) {
> NewLoop = new Loop();
> if (ParentLoop)
> ParentLoop->addChildLoop(NewLoop);
> @@ -163,7 +292,7 @@ static void CloneLoopBlocks(Loop *L, Val
> // For each block in the original loop, create a new copy,
> // and update the value map with the newly created values.
> for (LoopBlocksDFS::RPOIterator BB = BlockBegin; BB != BlockEnd; ++BB) {
> - BasicBlock *NewBB = CloneBasicBlock(*BB, VMap, ".prol", F);
> + BasicBlock *NewBB = CloneBasicBlock(*BB, VMap, "." + suffix, F);
> NewBlocks.push_back(NewBB);
>
> if (NewLoop)
> @@ -179,16 +308,17 @@ static void CloneLoopBlocks(Loop *L, Val
> }
>
> if (Latch == *BB) {
> - // For the last block, if UnrollProlog is true, create a direct jump to
> - // InsertBot. If not, create a loop back to cloned head.
> + // For the last block, if CreateRemainderLoop is false, create a direct
> + // jump to InsertBot. If not, create a loop back to cloned head.
> VMap.erase((*BB)->getTerminator());
> BasicBlock *FirstLoopBB = cast<BasicBlock>(VMap[Header]);
> BranchInst *LatchBR = cast<BranchInst>(NewBB->getTerminator());
> IRBuilder<> Builder(LatchBR);
> - if (UnrollProlog) {
> + if (!CreateRemainderLoop) {
> Builder.CreateBr(InsertBot);
> } else {
> - PHINode *NewIdx = PHINode::Create(NewIter->getType(), 2, "prol.iter",
> + PHINode *NewIdx = PHINode::Create(NewIter->getType(), 2,
> + suffix + ".iter",
> FirstLoopBB->getFirstNonPHI());
> Value *IdxSub =
> Builder.CreateSub(NewIdx, ConstantInt::get(NewIdx->getType(), 1),
> @@ -207,9 +337,15 @@ static void CloneLoopBlocks(Loop *L, Val
> // cloned loop.
> for (BasicBlock::iterator I = Header->begin(); isa<PHINode>(I); ++I) {
> PHINode *NewPHI = cast<PHINode>(VMap[&*I]);
> - if (UnrollProlog) {
> - VMap[&*I] = NewPHI->getIncomingValueForBlock(Preheader);
> - cast<BasicBlock>(VMap[Header])->getInstList().erase(NewPHI);
> + if (!CreateRemainderLoop) {
> + if (UseEpilogRemainder) {
> + unsigned idx = NewPHI->getBasicBlockIndex(Preheader);
> + NewPHI->setIncomingBlock(idx, InsertTop);
> + NewPHI->removeIncomingValue(Latch, false);
> + } else {
> + VMap[&*I] = NewPHI->getIncomingValueForBlock(Preheader);
> + cast<BasicBlock>(VMap[Header])->getInstList().erase(NewPHI);
> + }
> } else {
> unsigned idx = NewPHI->getBasicBlockIndex(Preheader);
> NewPHI->setIncomingBlock(idx, InsertTop);
> @@ -254,7 +390,7 @@ static void CloneLoopBlocks(Loop *L, Val
> }
> }
>
> -/// Insert code in the prolog code when unrolling a loop with a
> +/// Insert code in the prolog/epilog code when unrolling a loop with a
> /// run-time trip-count.
> ///
> /// This method assumes that the loop unroll factor is total number
> @@ -266,6 +402,7 @@ static void CloneLoopBlocks(Loop *L, Val
> /// instruction in SimplifyCFG.cpp. Then, the backend decides how code for
> /// the switch instruction is generated.
> ///
> +/// ***Prolog case***
> /// extraiters = tripcount % loopfactor
> /// if (extraiters == 0) jump Loop:
> /// else jump Prol
> @@ -277,17 +414,35 @@ static void CloneLoopBlocks(Loop *L, Val
> /// ...
> /// End:
> ///
> -bool llvm::UnrollRuntimeLoopProlog(Loop *L, unsigned Count,
> - bool AllowExpensiveTripCount, LoopInfo *LI,
> - ScalarEvolution *SE, DominatorTree *DT,
> - bool PreserveLCSSA) {
> - // For now, only unroll loops that contain a single exit.
> +/// ***Epilog case***
> +/// extraiters = tripcount % loopfactor
> +/// if (extraiters == tripcount) jump LoopExit:
> +/// unroll_iters = tripcount - extraiters
> +/// Loop: LoopBody; (executes unroll_iter times);
> +/// unroll_iter -= 1
> +/// if (unroll_iter != 0) jump Loop:
> +/// LoopExit:
> +/// if (extraiters == 0) jump EpilExit:
> +/// Epil: LoopBody; (executes extraiters times)
> +/// extraiters -= 1 // Omitted if unroll factor is 2.
> +/// if (extraiters != 0) jump Epil: // Omitted if unroll factor is 2.
> +/// EpilExit:
> +
> +bool llvm::UnrollRuntimeLoopRemainder(Loop *L, unsigned Count,
> + bool AllowExpensiveTripCount,
> + bool UseEpilogRemainder,
> + LoopInfo *LI, ScalarEvolution *SE,
> + DominatorTree *DT, bool PreserveLCSSA) {
> + // for now, only unroll loops that contain a single exit
> if (!L->getExitingBlock())
> return false;
>
> // Make sure the loop is in canonical form, and there is a single
> // exit block only.
> - if (!L->isLoopSimplifyForm() || !L->getUniqueExitBlock())
> + if (!L->isLoopSimplifyForm())
> + return false;
> + BasicBlock *Exit = L->getUniqueExitBlock(); // successor out of loop
> + if (!Exit)
> return false;
>
> // Use Scalar Evolution to compute the trip count. This allows more loops to
> @@ -311,8 +466,8 @@ bool llvm::UnrollRuntimeLoopProlog(Loop
> return false;
>
> BasicBlock *Header = L->getHeader();
> - BasicBlock *PH = L->getLoopPreheader();
> - BranchInst *PreHeaderBR = cast<BranchInst>(PH->getTerminator());
> + BasicBlock *PreHeader = L->getLoopPreheader();
> + BranchInst *PreHeaderBR = cast<BranchInst>(PreHeader->getTerminator());
> const DataLayout &DL = Header->getModule()->getDataLayout();
> SCEVExpander Expander(*SE, DL, "loop-unroll");
> if (!AllowExpensiveTripCount &&
> @@ -330,26 +485,75 @@ bool llvm::UnrollRuntimeLoopProlog(Loop
> SE->forgetLoop(ParentLoop);
>
> BasicBlock *Latch = L->getLoopLatch();
> - // It helps to split the original preheader twice, one for the end of the
> - // prolog code and one for a new loop preheader.
> - BasicBlock *PEnd = SplitEdge(PH, Header, DT, LI);
> - BasicBlock *NewPH = SplitBlock(PEnd, PEnd->getTerminator(), DT, LI);
> - PreHeaderBR = cast<BranchInst>(PH->getTerminator());
>
> + // Loop structure is the following:
> + //
> + // PreHeader
> + // Header
> + // ...
> + // Latch
> + // Exit
> +
> + BasicBlock *NewPreHeader;
> + BasicBlock *NewExit = nullptr;
> + BasicBlock *PrologExit = nullptr;
> + BasicBlock *EpilogPreHeader = nullptr;
> + BasicBlock *PrologPreHeader = nullptr;
> +
> + if (UseEpilogRemainder) {
> + // If epilog remainder
> + // Split PreHeader to insert a branch around loop for unrolling.
> + NewPreHeader = SplitBlock(PreHeader, PreHeader->getTerminator(), DT, LI);
> + NewPreHeader->setName(PreHeader->getName() + ".new");
> + // Split Exit to create phi nodes from branch above.
> + SmallVector<BasicBlock*, 4> Preds(predecessors(Exit));
> + NewExit = SplitBlockPredecessors(Exit, Preds, ".unr-lcssa",
> + DT, LI, PreserveLCSSA);
> + // Split NewExit to insert epilog remainder loop.
> + EpilogPreHeader = SplitBlock(NewExit, NewExit->getTerminator(), DT, LI);
> + EpilogPreHeader->setName(Header->getName() + ".epil.preheader");
> + } else {
> + // If prolog remainder
> + // Split the original preheader twice to insert prolog remainder loop
> + PrologPreHeader = SplitEdge(PreHeader, Header, DT, LI);
> + PrologPreHeader->setName(Header->getName() + ".prol.preheader");
> + PrologExit = SplitBlock(PrologPreHeader, PrologPreHeader->getTerminator(),
> + DT, LI);
> + PrologExit->setName(Header->getName() + ".prol.loopexit");
> + // Split PrologExit to get NewPreHeader.
> + NewPreHeader = SplitBlock(PrologExit, PrologExit->getTerminator(), DT, LI);
> + NewPreHeader->setName(PreHeader->getName() + ".new");
> + }
> + // Loop structure should be the following:
> + // Epilog Prolog
> + //
> + // PreHeader PreHeader
> + // *NewPreHeader *PrologPreHeader
> + // Header *PrologExit
> + // ... *NewPreHeader
> + // Latch Header
> + // *NewExit ...
> + // *EpilogPreHeader Latch
> + // Exit Exit
> +
> + // Calculate conditions for branch around loop for unrolling
> + // in epilog case and around prolog remainder loop in prolog case.
> // Compute the number of extra iterations required, which is:
> - // extra iterations = run-time trip count % (loop unroll factor + 1)
> + // extra iterations = run-time trip count % loop unroll factor
> + PreHeaderBR = cast<BranchInst>(PreHeader->getTerminator());
> Value *TripCount = Expander.expandCodeFor(TripCountSC, TripCountSC->getType(),
> PreHeaderBR);
> Value *BECount = Expander.expandCodeFor(BECountSC, BECountSC->getType(),
> PreHeaderBR);
> -
> IRBuilder<> B(PreHeaderBR);
> Value *ModVal;
> // Calculate ModVal = (BECount + 1) % Count.
> // Note that TripCount is BECount + 1.
> if (isPowerOf2_32(Count)) {
> + // When Count is power of 2 we don't BECount for epilog case, however we'll
> + // need it for a branch around unrolling loop for prolog case.
> ModVal = B.CreateAnd(TripCount, Count - 1, "xtraiter");
> - // 1. There are no iterations to be run in the prologue loop.
> + // 1. There are no iterations to be run in the prolog/epilog loop.
> // OR
> // 2. The addition computing TripCount overflowed.
> //
> @@ -371,18 +575,18 @@ bool llvm::UnrollRuntimeLoopProlog(Loop
> ConstantInt::get(BECount->getType(), Count),
> "xtraiter");
> }
> - Value *BranchVal = B.CreateIsNotNull(ModVal, "lcmp.mod");
> -
> - // Branch to either the extra iterations or the cloned/unrolled loop.
> - // We will fix up the true branch label when adding loop body copies.
> - B.CreateCondBr(BranchVal, PEnd, PEnd);
> - assert(PreHeaderBR->isUnconditional() &&
> - PreHeaderBR->getSuccessor(0) == PEnd &&
> - "CFG edges in Preheader are not correct");
> + Value *CmpOperand =
> + UseEpilogRemainder ? TripCount :
> + ConstantInt::get(TripCount->getType(), 0);
> + Value *BranchVal = B.CreateICmpNE(ModVal, CmpOperand, "lcmp.mod");
> + BasicBlock *FirstLoop = UseEpilogRemainder ? NewPreHeader : PrologPreHeader;
> + BasicBlock *SecondLoop = UseEpilogRemainder ? NewExit : PrologExit;
> + // Branch to either remainder (extra iterations) loop or unrolling loop.
> + B.CreateCondBr(BranchVal, FirstLoop, SecondLoop);
> PreHeaderBR->eraseFromParent();
> Function *F = Header->getParent();
> // Get an ordered list of blocks in the loop to help with the ordering of the
> - // cloned blocks in the prolog code.
> + // cloned blocks in the prolog/epilog code
> LoopBlocksDFS LoopBlocks(L);
> LoopBlocks.perform(LI);
>
> @@ -394,17 +598,38 @@ bool llvm::UnrollRuntimeLoopProlog(Loop
> std::vector<BasicBlock *> NewBlocks;
> ValueToValueMapTy VMap;
>
> - bool UnrollPrologue = Count == 2;
> + // For unroll factor 2 remainder loop will have 1 iterations.
> + // Do not create 1 iteration loop.
> + bool CreateRemainderLoop = (Count != 2);
>
> // Clone all the basic blocks in the loop. If Count is 2, we don't clone
> // the loop, otherwise we create a cloned loop to execute the extra
> // iterations. This function adds the appropriate CFG connections.
> - CloneLoopBlocks(L, ModVal, UnrollPrologue, PH, PEnd, NewBlocks, LoopBlocks,
> - VMap, LI);
> + BasicBlock *InsertBot = UseEpilogRemainder ? Exit : PrologExit;
> + BasicBlock *InsertTop = UseEpilogRemainder ? EpilogPreHeader : PrologPreHeader;
> + CloneLoopBlocks(L, ModVal, CreateRemainderLoop, UseEpilogRemainder, InsertTop,
> + InsertBot, NewPreHeader, NewBlocks, LoopBlocks, VMap, LI);
> +
> + // Insert the cloned blocks into the function.
> + F->getBasicBlockList().splice(InsertBot->getIterator(),
> + F->getBasicBlockList(),
> + NewBlocks[0]->getIterator(),
> + F->end());
>
> - // Insert the cloned blocks into the function just before the original loop.
> - F->getBasicBlockList().splice(PEnd->getIterator(), F->getBasicBlockList(),
> - NewBlocks[0]->getIterator(), F->end());
> + // Loop structure should be the following:
> + // Epilog Prolog
> + //
> + // PreHeader PreHeader
> + // NewPreHeader PrologPreHeader
> + // Header PrologHeader
> + // ... ...
> + // Latch PrologLatch
> + // NewExit PrologExit
> + // EpilogPreHeader NewPreHeader
> + // EpilogHeader Header
> + // ... ...
> + // EpilogLatch Latch
> + // Exit Exit
>
> // Rewrite the cloned instruction operands to use the values created when the
> // clone is created.
> @@ -415,11 +640,38 @@ bool llvm::UnrollRuntimeLoopProlog(Loop
> }
> }
>
> - // Connect the prolog code to the original loop and update the
> - // PHI functions.
> - BasicBlock *LastLoopBB = cast<BasicBlock>(VMap[Latch]);
> - ConnectProlog(L, BECount, Count, LastLoopBB, PEnd, PH, NewPH, VMap, DT, LI,
> - PreserveLCSSA);
> + if (UseEpilogRemainder) {
> + // Connect the epilog code to the original loop and update the
> + // PHI functions.
> + ConnectEpilog(L, ModVal, NewExit, Exit, PreHeader,
> + EpilogPreHeader, NewPreHeader, VMap, DT, LI,
> + PreserveLCSSA);
> +
> + // Update counter in loop for unrolling.
> + // I should be multiply of Count.
> + IRBuilder<> B2(NewPreHeader->getTerminator());
> + Value *TestVal = B2.CreateSub(TripCount, ModVal, "unroll_iter");
> + BranchInst *LatchBR = cast<BranchInst>(Latch->getTerminator());
> + B2.SetInsertPoint(LatchBR);
> + PHINode *NewIdx = PHINode::Create(TestVal->getType(), 2, "niter",
> + Header->getFirstNonPHI());
> + Value *IdxSub =
> + B2.CreateSub(NewIdx, ConstantInt::get(NewIdx->getType(), 1),
> + NewIdx->getName() + ".nsub");
> + Value *IdxCmp;
> + if (LatchBR->getSuccessor(0) == Header)
> + IdxCmp = B2.CreateIsNotNull(IdxSub, NewIdx->getName() + ".ncmp");
> + else
> + IdxCmp = B2.CreateIsNull(IdxSub, NewIdx->getName() + ".ncmp");
> + NewIdx->addIncoming(TestVal, NewPreHeader);
> + NewIdx->addIncoming(IdxSub, Latch);
> + LatchBR->setCondition(IdxCmp);
> + } else {
> + // Connect the prolog code to the original loop and update the
> + // PHI functions.
> + ConnectProlog(L, BECount, Count, PrologExit, PreHeader, NewPreHeader,
> + VMap, DT, LI, PreserveLCSSA);
> + }
> NumRuntimeUnrolled++;
> return true;
> }
>
> Modified: llvm/trunk/test/Transforms/LoopUnroll/AArch64/runtime-loop.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/AArch64/runtime-loop.ll?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopUnroll/AArch64/runtime-loop.ll (original)
> +++ llvm/trunk/test/Transforms/LoopUnroll/AArch64/runtime-loop.ll Tue Apr 5 07:19:35 2016
> @@ -1,13 +1,21 @@
> -; RUN: opt < %s -S -loop-unroll -mtriple aarch64 -mcpu=cortex-a57 | FileCheck %s
> +; RUN: opt < %s -S -loop-unroll -mtriple aarch64 -mcpu=cortex-a57 | FileCheck %s -check-prefix=EPILOG
> +; RUN: opt < %s -S -loop-unroll -mtriple aarch64 -mcpu=cortex-a57 -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG
>
> ; Tests for unrolling loops with run-time trip counts
>
> -; CHECK: %xtraiter = and i32 %n
> -; CHECK: %lcmp.mod = icmp ne i32 %xtraiter, 0
> -; CHECK: br i1 %lcmp.mod, label %for.body.prol, label %for.body.preheader.split
> +; EPILOG: %xtraiter = and i32 %n
> +; EPILOG: %lcmp.mod = icmp ne i32 %xtraiter, %n
> +; EPILOG: br i1 %lcmp.mod, label %for.body.preheader.new, label %for.end.loopexit.unr-lcssa
>
> -; CHECK: for.body.prol:
> -; CHECK: for.body:
> +; PROLOG: %xtraiter = and i32 %n
> +; PROLOG: %lcmp.mod = icmp ne i32 %xtraiter, 0
> +; PROLOG: br i1 %lcmp.mod, label %for.body.prol.preheader, label %for.body.prol.loopexit
> +
> +; EPILOG: for.body:
> +; EPILOG: for.body.epil:
> +
> +; PROLOG: for.body.prol:
> +; PROLOG: for.body:
>
> define i32 @test(i32* nocapture %a, i32 %n) nounwind uwtable readonly {
> entry:
>
> Modified: llvm/trunk/test/Transforms/LoopUnroll/PowerPC/a2-unrolling.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/PowerPC/a2-unrolling.ll?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopUnroll/PowerPC/a2-unrolling.ll (original)
> +++ llvm/trunk/test/Transforms/LoopUnroll/PowerPC/a2-unrolling.ll Tue Apr 5 07:19:35 2016
> @@ -1,4 +1,5 @@
> -; RUN: opt < %s -S -mtriple=powerpc64-unknown-linux-gnu -mcpu=a2 -loop-unroll | FileCheck %s
> +; RUN: opt < %s -S -mtriple=powerpc64-unknown-linux-gnu -mcpu=a2 -loop-unroll | FileCheck %s -check-prefix=EPILOG
> +; RUN: opt < %s -S -mtriple=powerpc64-unknown-linux-gnu -mcpu=a2 -loop-unroll -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG
> define void @unroll_opt_for_size() nounwind optsize {
> entry:
> br label %loop
> @@ -13,11 +14,17 @@ exit:
> ret void
> }
>
> -; CHECK-LABEL: @unroll_opt_for_size
> -; CHECK: add
> -; CHECK-NEXT: add
> -; CHECK-NEXT: add
> -; CHECK: icmp
> +; EPILOG-LABEL: @unroll_opt_for_size
> +; EPILOG: add
> +; EPILOG-NEXT: add
> +; EPILOG-NEXT: add
> +; EPILOG: icmp
> +
> +; PROLOG-LABEL: @unroll_opt_for_size
> +; PROLOG: add
> +; PROLOG-NEXT: add
> +; PROLOG-NEXT: add
> +; PROLOG: icmp
>
> define i32 @test(i32* nocapture %a, i32 %n) nounwind uwtable readonly {
> entry:
> @@ -40,8 +47,13 @@ for.end:
> ret i32 %sum.0.lcssa
> }
>
> -; CHECK-LABEL: @test
> -; CHECK: for.body.prol{{.*}}:
> -; CHECK: for.body:
> -; CHECK: br i1 %exitcond.7, label %for.end.loopexit{{.*}}, label %for.body
> +; EPILOG-LABEL: @test
> +; EPILOG: for.body:
> +; EPILOG: br i1 %niter.ncmp.7, label %for.end.loopexit{{.*}}, label %for.body
> +; EPILOG: for.body.epil{{.*}}:
> +
> +; PROLOG-LABEL: @test
> +; PROLOG: for.body.prol{{.*}}:
> +; PROLOG: for.body:
> +; PROLOG: br i1 %exitcond.7, label %for.end.loopexit{{.*}}, label %for.body
>
>
> Modified: llvm/trunk/test/Transforms/LoopUnroll/X86/mmx.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/X86/mmx.ll?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopUnroll/X86/mmx.ll (original)
> +++ llvm/trunk/test/Transforms/LoopUnroll/X86/mmx.ll Tue Apr 5 07:19:35 2016
> @@ -14,9 +14,9 @@ for.body:
>
> exit: ; preds = %for.body
> %ret = phi x86_mmx [ undef, %for.body ]
> - ; CHECK: %[[ret_unr:.*]] = phi x86_mmx [ undef,
> - ; CHECK: %[[ret_ph:.*]] = phi x86_mmx [ undef,
> - ; CHECK: %[[ret:.*]] = phi x86_mmx [ %[[ret_unr]], {{.*}} ], [ %[[ret_ph]]
> + ; CHECK: %[[ret_ph:.*]] = phi x86_mmx [ undef, %entry
> + ; CHECK: %[[ret_ph1:.*]] = phi x86_mmx [ undef,
> + ; CHECK: %[[ret:.*]] = phi x86_mmx [ %[[ret_ph]], {{.*}} ], [ %[[ret_ph1]],
> ; CHECK: ret x86_mmx %[[ret]]
> ret x86_mmx %ret
> }
>
> Modified: llvm/trunk/test/Transforms/LoopUnroll/high-cost-trip-count-computation.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/high-cost-trip-count-computation.ll?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopUnroll/high-cost-trip-count-computation.ll (original)
> +++ llvm/trunk/test/Transforms/LoopUnroll/high-cost-trip-count-computation.ll Tue Apr 5 07:19:35 2016
> @@ -34,7 +34,7 @@ define i32 @test2(i64* %loc, i64 %conv7)
> ; CHECK: udiv
> ; CHECK: udiv
> ; CHECK-NOT: udiv
> -; CHECK-LABEL: for.body.prol
> +; CHECK-LABEL: for.body
> entry:
> %rem0 = load i64, i64* %loc, align 8
> %ExpensiveComputation = udiv i64 %rem0, 42 ; <<< Extra computations are added to the trip-count expression
>
> Modified: llvm/trunk/test/Transforms/LoopUnroll/runtime-loop.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/runtime-loop.ll?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopUnroll/runtime-loop.ll (original)
> +++ llvm/trunk/test/Transforms/LoopUnroll/runtime-loop.ll Tue Apr 5 07:19:35 2016
> @@ -1,18 +1,30 @@
> -; RUN: opt < %s -S -loop-unroll -unroll-runtime=true | FileCheck %s
> +; RUN: opt < %s -S -loop-unroll -unroll-runtime=true | FileCheck %s -check-prefix=EPILOG
> +; RUN: opt < %s -S -loop-unroll -unroll-runtime=true -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG
>
> target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
>
> ; Tests for unrolling loops with run-time trip counts
>
> -; CHECK: %xtraiter = and i32 %n
> -; CHECK: %lcmp.mod = icmp ne i32 %xtraiter, 0
> -; CHECK: br i1 %lcmp.mod, label %for.body.prol, label %for.body.preheader.split
> -
> -; CHECK: for.body.prol:
> -; CHECK: %indvars.iv.prol = phi i64 [ %indvars.iv.next.prol, %for.body.prol ], [ 0, %for.body.preheader ]
> -; CHECK: %prol.iter.sub = sub i32 %prol.iter, 1
> -; CHECK: %prol.iter.cmp = icmp ne i32 %prol.iter.sub, 0
> -; CHECK: br i1 %prol.iter.cmp, label %for.body.prol, label %for.body.preheader.split, !llvm.loop !0
> +; EPILOG: %xtraiter = and i32 %n
> +; EPILOG: %lcmp.mod = icmp ne i32 %xtraiter, %n
> +; EPILOG: br i1 %lcmp.mod, label %for.body.preheader.new, label %for.end.loopexit.unr-lcssa
> +
> +; PROLOG: %xtraiter = and i32 %n
> +; PROLOG: %lcmp.mod = icmp ne i32 %xtraiter, 0
> +; PROLOG: br i1 %lcmp.mod, label %for.body.prol.preheader, label %for.body.prol.loopexit
> +
> +; EPILOG: for.body.epil:
> +; EPILOG: %indvars.iv.epil = phi i64 [ %indvars.iv.next.epil, %for.body.epil ], [ %indvars.iv.unr, %for.body.epil.preheader ]
> +; EPILOG: %epil.iter.sub = sub i32 %epil.iter, 1
> +; EPILOG: %epil.iter.cmp = icmp ne i32 %epil.iter.sub, 0
> +; EPILOG: br i1 %epil.iter.cmp, label %for.body.epil, label %for.end.loopexit.epilog-lcssa, !llvm.loop !0
> +
> +; PROLOG: for.body.prol:
> +; PROLOG: %indvars.iv.prol = phi i64 [ %indvars.iv.next.prol, %for.body.prol ], [ 0, %for.body.prol.preheader ]
> +; PROLOG: %prol.iter.sub = sub i32 %prol.iter, 1
> +; PROLOG: %prol.iter.cmp = icmp ne i32 %prol.iter.sub, 0
> +; PROLOG: br i1 %prol.iter.cmp, label %for.body.prol, label %for.body.prol.loopexit, !llvm.loop !0
> +
>
> define i32 @test(i32* nocapture %a, i32 %n) nounwind uwtable readonly {
> entry:
> @@ -39,8 +51,11 @@ for.end:
> ; Still try to completely unroll loops with compile-time trip counts
> ; even if the -unroll-runtime is specified
>
> -; CHECK: for.body:
> -; CHECK-NOT: for.body.prol:
> +; EPILOG: for.body:
> +; EPILOG-NOT: for.body.epil:
> +
> +; PROLOG: for.body:
> +; PROLOG-NOT: for.body.prol:
>
> define i32 @test1(i32* nocapture %a) nounwind uwtable readonly {
> entry:
> @@ -64,7 +79,8 @@ for.end:
> ; This is test 2007-05-09-UnknownTripCount.ll which can be unrolled now
> ; if the -unroll-runtime option is turned on
>
> -; CHECK: bb72.2:
> +; EPILOG: bb72.2:
> +; PROLOG: bb72.2:
>
> define void @foo(i32 %trips) {
> entry:
> @@ -86,8 +102,11 @@ cond_true138:
>
> ; Test run-time unrolling for a loop that counts down by -2.
>
> -; CHECK: for.body.prol:
> -; CHECK: br i1 %prol.iter.cmp, label %for.body.prol, label %for.body.preheader.split
> +; EPILOG: for.body.epil:
> +; EPILOG: br i1 %epil.iter.cmp, label %for.body.epil, label %for.cond.for.end_crit_edge.epilog-lcssa
> +
> +; PROLOG: for.body.prol:
> +; PROLOG: br i1 %prol.iter.cmp, label %for.body.prol, label %for.body.prol.loopexit
>
> define zeroext i16 @down(i16* nocapture %p, i32 %len) nounwind uwtable readonly {
> entry:
> @@ -116,8 +135,11 @@ for.end:
> }
>
> ; Test run-time unrolling disable metadata.
> -; CHECK: for.body:
> -; CHECK-NOT: for.body.prol:
> +; EPILOG: for.body:
> +; EPILOG-NOT: for.body.epil:
> +
> +; PROLOG: for.body:
> +; PROLOG-NOT: for.body.prol:
>
> define zeroext i16 @test2(i16* nocapture %p, i32 %len) nounwind uwtable readonly {
> entry:
> @@ -148,6 +170,8 @@ for.end:
> !0 = distinct !{!0, !1}
> !1 = !{!"llvm.loop.unroll.runtime.disable"}
>
> -; CHECK: !0 = distinct !{!0, !1}
> -; CHECK: !1 = !{!"llvm.loop.unroll.disable"}
> +; EPILOG: !0 = distinct !{!0, !1}
> +; EPILOG: !1 = !{!"llvm.loop.unroll.disable"}
>
> +; PROLOG: !0 = distinct !{!0, !1}
> +; PROLOG: !1 = !{!"llvm.loop.unroll.disable"}
>
> Modified: llvm/trunk/test/Transforms/LoopUnroll/runtime-loop1.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/runtime-loop1.ll?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopUnroll/runtime-loop1.ll (original)
> +++ llvm/trunk/test/Transforms/LoopUnroll/runtime-loop1.ll Tue Apr 5 07:19:35 2016
> @@ -1,19 +1,35 @@
> -; RUN: opt < %s -S -loop-unroll -unroll-runtime -unroll-count=2 | FileCheck %s
> +; RUN: opt < %s -S -loop-unroll -unroll-runtime -unroll-count=2 | FileCheck %s -check-prefix=EPILOG
> +; RUN: opt < %s -S -loop-unroll -unroll-runtime -unroll-count=2 -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG
>
> ; This tests that setting the unroll count works
>
> -; CHECK: for.body.preheader:
> -; CHECK: br {{.*}} label %for.body.prol, label %for.body.preheader.split, !dbg [[PH_LOC:![0-9]+]]
> -; CHECK: for.body.prol:
> -; CHECK: br label %for.body.preheader.split, !dbg [[BODY_LOC:![0-9]+]]
> -; CHECK: for.body.preheader.split:
> -; CHECK: br {{.*}} label %for.end.loopexit, label %for.body.preheader.split.split, !dbg [[PH_LOC]]
> -; CHECK: for.body:
> -; CHECK: br i1 %exitcond.1, label %for.end.loopexit.unr-lcssa, label %for.body, !dbg [[BODY_LOC]]
> -; CHECK-NOT: br i1 %exitcond.4, label %for.end.loopexit{{.*}}, label %for.body
>
> -; CHECK-DAG: [[PH_LOC]] = !DILocation(line: 101, column: 1, scope: !{{.*}})
> -; CHECK-DAG: [[BODY_LOC]] = !DILocation(line: 102, column: 1, scope: !{{.*}})
> +; EPILOG: for.body.preheader:
> +; EPILOG: br i1 %lcmp.mod, label %for.body.preheader.new, label %for.end.loopexit.unr-lcssa, !dbg [[PH_LOC:![0-9]+]]
> +; EPILOG: for.body:
> +; EPILOG: br i1 %niter.ncmp.1, label %for.end.loopexit.unr-lcssa.loopexit, label %for.body, !dbg [[BODY_LOC:![0-9]+]]
> +; EPILOG-NOT: br i1 %niter.ncmp.2, label %for.end.loopexit{{.*}}, label %for.body
> +; EPILOG: for.body.epil.preheader:
> +; EPILOG: br label %for.body.epil, !dbg [[EXIT_LOC:![0-9]+]]
> +; EPILOG: for.body.epil:
> +; EPILOG: br label %for.end.loopexit.epilog-lcssa, !dbg [[BODY_LOC:![0-9]+]]
> +
> +; EPILOG-DAG: [[PH_LOC]] = !DILocation(line: 101, column: 1, scope: !{{.*}})
> +; EPILOG-DAG: [[BODY_LOC]] = !DILocation(line: 102, column: 1, scope: !{{.*}})
> +; EPILOG-DAG: [[EXIT_LOC]] = !DILocation(line: 103, column: 1, scope: !{{.*}})
> +
> +; PROLOG: for.body.preheader:
> +; PROLOG: br {{.*}} label %for.body.prol.preheader, label %for.body.prol.loopexit, !dbg [[PH_LOC:![0-9]+]]
> +; PROLOG: for.body.prol:
> +; PROLOG: br label %for.body.prol.loopexit, !dbg [[BODY_LOC:![0-9]+]]
> +; PROLOG: for.body.prol.loopexit:
> +; PROLOG: br {{.*}} label %for.end.loopexit, label %for.body.preheader.new, !dbg [[PH_LOC]]
> +; PROLOG: for.body:
> +; PROLOG: br i1 %exitcond.1, label %for.end.loopexit.unr-lcssa, label %for.body, !dbg [[BODY_LOC]]
> +; PROLOG-NOT: br i1 %exitcond.4, label %for.end.loopexit{{.*}}, label %for.body
> +
> +; PROLOG-DAG: [[PH_LOC]] = !DILocation(line: 101, column: 1, scope: !{{.*}})
> +; PROLOG-DAG: [[BODY_LOC]] = !DILocation(line: 102, column: 1, scope: !{{.*}})
>
> define i32 @test(i32* nocapture %a, i32 %n) nounwind uwtable readonly !dbg !6 {
> entry:
>
> Modified: llvm/trunk/test/Transforms/LoopUnroll/runtime-loop2.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/runtime-loop2.ll?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopUnroll/runtime-loop2.ll (original)
> +++ llvm/trunk/test/Transforms/LoopUnroll/runtime-loop2.ll Tue Apr 5 07:19:35 2016
> @@ -1,12 +1,18 @@
> -; RUN: opt < %s -S -loop-unroll -unroll-threshold=25 -unroll-runtime -unroll-count=8 | FileCheck %s
> +; RUN: opt < %s -S -loop-unroll -unroll-threshold=25 -unroll-runtime -unroll-count=8 | FileCheck %s -check-prefix=EPILOG
> +; RUN: opt < %s -S -loop-unroll -unroll-threshold=25 -unroll-runtime -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG
>
> ; Choose a smaller, power-of-two, unroll count if the loop is too large.
> ; This test makes sure we're not unrolling 'odd' counts
>
> -; CHECK: for.body.prol:
> -; CHECK: for.body:
> -; CHECK: br i1 %exitcond.3, label %for.end.loopexit{{.*}}, label %for.body
> -; CHECK-NOT: br i1 %exitcond.4, label %for.end.loopexit{{.*}}, label %for.body
> +; EPILOG: for.body:
> +; EPILOG: br i1 %niter.ncmp.3, label %for.end.loopexit.unr-lcssa.loopexit{{.*}}, label %for.body
> +; EPILOG-NOT: br i1 %niter.ncmp.4, label %for.end.loopexit.unr-lcssa.loopexit{{.*}}, label %for.body
> +; EPILOG: for.body.epil:
> +
> +; PROLOG: for.body.prol:
> +; PROLOG: for.body:
> +; PROLOG: br i1 %exitcond.3, label %for.end.loopexit{{.*}}, label %for.body
> +; PROLOG-NOT: br i1 %exitcond.4, label %for.end.loopexit{{.*}}, label %for.body
>
> define i32 @test(i32* nocapture %a, i32 %n) nounwind uwtable readonly {
> entry:
>
> Modified: llvm/trunk/test/Transforms/LoopUnroll/runtime-loop4.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/runtime-loop4.ll?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopUnroll/runtime-loop4.ll (original)
> +++ llvm/trunk/test/Transforms/LoopUnroll/runtime-loop4.ll Tue Apr 5 07:19:35 2016
> @@ -1,13 +1,21 @@
> -; RUN: opt < %s -S -O2 -unroll-runtime=true | FileCheck %s
> +; RUN: opt < %s -S -O2 -unroll-runtime=true | FileCheck %s -check-prefix=EPILOG
> +; RUN: opt < %s -S -O2 -unroll-runtime=true -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG
>
> ; Check runtime unrolling prologue can be promoted by LICM pass.
>
> -; CHECK: entry:
> -; CHECK: %xtraiter
> -; CHECK: %lcmp.mod
> -; CHECK: loop1:
> -; CHECK: br i1 %lcmp.mod
> -; CHECK: loop2.prol:
> +; EPILOG: entry:
> +; EPILOG: %xtraiter
> +; EPILOG: %lcmp.mod
> +; EPILOG: loop1:
> +; EPILOG: br i1 %lcmp.mod
> +; EPILOG: loop2.epil:
> +
> +; PROLOG: entry:
> +; PROLOG: %xtraiter
> +; PROLOG: %lcmp.mod
> +; PROLOG: loop1:
> +; PROLOG: br i1 %lcmp.mod
> +; PROLOG: loop2.prol:
>
> define void @unroll(i32 %iter, i32* %addr1, i32* %addr2) nounwind {
> entry:
>
> Modified: llvm/trunk/test/Transforms/LoopUnroll/runtime-loop5.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/runtime-loop5.ll?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopUnroll/runtime-loop5.ll (original)
> +++ llvm/trunk/test/Transforms/LoopUnroll/runtime-loop5.ll Tue Apr 5 07:19:35 2016
> @@ -11,9 +11,6 @@ entry:
> %cmp1 = icmp eq i3 %n, 0
> br i1 %cmp1, label %for.end, label %for.body
>
> -; UNROLL-16-NOT: for.body.prol:
> -; UNROLL-4: for.body.prol:
> -
> for.body: ; preds = %for.body, %entry
> ; UNROLL-16-LABEL: for.body:
> ; UNROLL-4-LABEL: for.body:
> @@ -39,6 +36,10 @@ for.body:
>
> ; UNROLL-16-LABEL: for.end
> ; UNROLL-4-LABEL: for.end
> +
> +; UNROLL-16-NOT: for.body.epil:
> +; UNROLL-4: for.body.epil:
> +
> for.end: ; preds = %for.body, %entry
> %sum.0.lcssa = phi i3 [ 0, %entry ], [ %add, %for.body ]
> ret i3 %sum.0.lcssa
>
> Modified: llvm/trunk/test/Transforms/LoopUnroll/tripcount-overflow.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/tripcount-overflow.ll?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopUnroll/tripcount-overflow.ll (original)
> +++ llvm/trunk/test/Transforms/LoopUnroll/tripcount-overflow.ll Tue Apr 5 07:19:35 2016
> @@ -13,13 +13,13 @@ target datalayout = "e-m:o-i64:64-f80:12
> ; CHECK: entry:
> ; CHECK-NEXT: %0 = add i32 %N, 1
> ; CHECK-NEXT: %xtraiter = and i32 %0, 1
> -; CHECK-NEXT: %lcmp.mod = icmp ne i32 %xtraiter, 0
> -; CHECK-NEXT: br i1 %lcmp.mod, label %while.body.prol, label %entry.split
> +; CHECK-NEXT: %lcmp.mod = icmp ne i32 %xtraiter, %0
> +; CHECK-NEXT: br i1 %lcmp.mod, label %entry.new, label %while.end.unr-lcssa
>
> -; CHECK: while.body.prol:
> -; CHECK: br label %entry.split
> +; CHECK: while.body.epil:
> +; CHECK: br label %while.end.epilog-lcssa
>
> -; CHECK: entry.split:
> +; CHECK: while.end.epilog-lcssa:
>
> ; Function Attrs: nounwind readnone ssp uwtable
> define i32 @foo(i32 %N) {
>
> Modified: llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll (original)
> +++ llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll Tue Apr 5 07:19:35 2016
> @@ -4,14 +4,14 @@
> ; RUN: opt < %s -O2 -S | FileCheck %s
>
> ; After loop unroll:
> -; %dec18 = add nsw i32 %dec18.in, -1
> +; %niter.nsub = add nsw i32 %niter, -1
> ; ...
> -; %dec18.1 = add nsw i32 %dec18, -1
> +; %niter.nsub.1 = add nsw i32 %niter.nsub, -1
> ; should be merged to:
> -; %dec18.1 = add nsw i32 %dec18.in, -2
> +; %dec18.1 = add nsw i32 %niter, -2
> ;
> ; CHECK-LABEL: @_Z3fn1v(
> -; CHECK: %dec18.1 = add nsw i32 %dec18.in, -2
> +; CHECK: %niter.nsub.1 = add i32 %niter, -2
>
> ; ModuleID = '<stdin>'
> target triple = "x86_64-unknown-linux-gnu"
>
> Modified: llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll?rev=265388&r1=265387&r2=265388&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll (original)
> +++ llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll Tue Apr 5 07:19:35 2016
> @@ -171,10 +171,6 @@ for.end:
> ; should be duplicated (original and 4x unrolled).
> ;
> ; CHECK-LABEL: @runtime_loop_with_count4(
> -; CHECK: for.body.prol:
> -; CHECK: store
> -; CHECK-NOT: store
> -; CHECK: br i1
> ; CHECK: for.body
> ; CHECK: store
> ; CHECK: store
> @@ -182,6 +178,10 @@ for.end:
> ; CHECK: store
> ; CHECK-NOT: store
> ; CHECK: br i1
> +; CHECK: for.body.epil:
> +; CHECK: store
> +; CHECK-NOT: store
> +; CHECK: br i1
> define void @runtime_loop_with_count4(i32* nocapture %a, i32 %b) {
> entry:
> %cmp3 = icmp sgt i32 %b, 0
> @@ -287,10 +287,6 @@ for.end:
> ; (original and 8x).
> ;
> ; CHECK-LABEL: @runtime_loop_with_enable(
> -; CHECK: for.body.prol:
> -; CHECK: store
> -; CHECK-NOT: store
> -; CHECK: br i1
> ; CHECK: for.body:
> ; CHECK: store i32
> ; CHECK: store i32
> @@ -302,6 +298,10 @@ for.end:
> ; CHECK: store i32
> ; CHECK-NOT: store i32
> ; CHECK: br i1
> +; CHECK: for.body.epil:
> +; CHECK: store
> +; CHECK-NOT: store
> +; CHECK: br i1
> define void @runtime_loop_with_enable(i32* nocapture %a, i32 %b) {
> entry:
> %cmp3 = icmp sgt i32 %b, 0
> @@ -328,16 +328,16 @@ for.end:
> ; should be duplicated (original and 3x unrolled).
> ;
> ; CHECK-LABEL: @runtime_loop_with_count3(
> -; CHECK: for.body.prol:
> -; CHECK: store
> -; CHECK-NOT: store
> -; CHECK: br i1
> ; CHECK: for.body
> ; CHECK: store
> ; CHECK: store
> ; CHECK: store
> ; CHECK-NOT: store
> ; CHECK: br i1
> +; CHECK: for.body.epil:
> +; CHECK: store
> +; CHECK-NOT: store
> +; CHECK: br i1
> define void @runtime_loop_with_count3(i32* nocapture %a, i32 %b) {
> entry:
> %cmp3 = icmp sgt i32 %b, 0
>
>
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