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-rw-r--r--llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp60
-rw-r--r--llvm/lib/Transforms/InstCombine/InstructionCombining.cpp6
-rw-r--r--llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp50
-rw-r--r--llvm/lib/Transforms/Scalar/GVN.cpp1
-rw-r--r--llvm/lib/Transforms/Scalar/NewGVN.cpp1
-rw-r--r--llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp2
-rw-r--r--llvm/lib/Transforms/Utils/LoopRotationUtils.cpp939
-rw-r--r--llvm/lib/Transforms/Utils/SimplifyCFG.cpp31
-rw-r--r--llvm/lib/Transforms/Vectorize/LoopVectorize.cpp8
-rw-r--r--llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp9
-rw-r--r--llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp14
-rw-r--r--llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp1
12 files changed, 564 insertions, 558 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index aa030294..127a506 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -60,6 +60,58 @@ static bool ShrinkDemandedConstant(Instruction *I, unsigned OpNo,
return true;
}
+/// Let N = 2 * M.
+/// Given an N-bit integer representing a pack of two M-bit integers,
+/// we can select one of the packed integers by right-shifting by either
+/// zero or M (which is the most straightforward to check if M is a power
+/// of 2), and then isolating the lower M bits. In this case, we can
+/// represent the shift as a select on whether the shr amount is nonzero.
+static Value *simplifyShiftSelectingPackedElement(Instruction *I,
+ const APInt &DemandedMask,
+ InstCombinerImpl &IC,
+ unsigned Depth) {
+ assert(I->getOpcode() == Instruction::LShr &&
+ "Only lshr instruction supported");
+
+ uint64_t ShlAmt;
+ Value *Upper, *Lower;
+ if (!match(I->getOperand(0),
+ m_OneUse(m_c_DisjointOr(
+ m_OneUse(m_Shl(m_Value(Upper), m_ConstantInt(ShlAmt))),
+ m_Value(Lower)))))
+ return nullptr;
+
+ if (!isPowerOf2_64(ShlAmt))
+ return nullptr;
+
+ const uint64_t DemandedBitWidth = DemandedMask.getActiveBits();
+ if (DemandedBitWidth > ShlAmt)
+ return nullptr;
+
+ // Check that upper demanded bits are not lost from lshift.
+ if (Upper->getType()->getScalarSizeInBits() < ShlAmt + DemandedBitWidth)
+ return nullptr;
+
+ KnownBits KnownLowerBits = IC.computeKnownBits(Lower, I, Depth);
+ if (!KnownLowerBits.getMaxValue().isIntN(ShlAmt))
+ return nullptr;
+
+ Value *ShrAmt = I->getOperand(1);
+ KnownBits KnownShrBits = IC.computeKnownBits(ShrAmt, I, Depth);
+
+ // Verify that ShrAmt is either exactly ShlAmt (which is a power of 2) or
+ // zero.
+ if (~KnownShrBits.Zero != ShlAmt)
+ return nullptr;
+
+ Value *ShrAmtZ =
+ IC.Builder.CreateICmpEQ(ShrAmt, Constant::getNullValue(ShrAmt->getType()),
+ ShrAmt->getName() + ".z");
+ Value *Select = IC.Builder.CreateSelect(ShrAmtZ, Lower, Upper);
+ Select->takeName(I);
+ return Select;
+}
+
/// Returns the bitwidth of the given scalar or pointer type. For vector types,
/// returns the element type's bitwidth.
static unsigned getBitWidth(Type *Ty, const DataLayout &DL) {
@@ -798,9 +850,13 @@ Value *InstCombinerImpl::SimplifyDemandedUseBits(Instruction *I,
Known >>= ShiftAmt;
if (ShiftAmt)
Known.Zero.setHighBits(ShiftAmt); // high bits known zero.
- } else {
- llvm::computeKnownBits(I, Known, Q, Depth);
+ break;
}
+ if (Value *V =
+ simplifyShiftSelectingPackedElement(I, DemandedMask, *this, Depth))
+ return V;
+
+ llvm::computeKnownBits(I, Known, Q, Depth);
break;
}
case Instruction::AShr: {
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 048cdf4..d56a1af 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1970,12 +1970,6 @@ Instruction *InstCombinerImpl::foldOpIntoPhi(Instruction &I, PHINode *PN,
NewPhiValues.push_back(nullptr);
OpsToMoveUseToIncomingBB.push_back(i);
- // If the InVal is an invoke at the end of the pred block, then we can't
- // insert a computation after it without breaking the edge.
- if (isa<InvokeInst>(InVal))
- if (cast<Instruction>(InVal)->getParent() == InBB)
- return nullptr;
-
// Do not push the operation across a loop backedge. This could result in
// an infinite combine loop, and is generally non-profitable (especially
// if the operation was originally outside the loop).
diff --git a/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp b/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp
index ae34b4e..e448230 100644
--- a/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp
+++ b/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp
@@ -120,6 +120,9 @@ static cl::opt<unsigned>
CostThreshold("dfa-cost-threshold",
cl::desc("Maximum cost accepted for the transformation"),
cl::Hidden, cl::init(50));
+
+extern cl::opt<bool> ProfcheckDisableMetadataFixes;
+
} // namespace llvm
static cl::opt<double> MaxClonedRate(
@@ -260,7 +263,11 @@ void DFAJumpThreading::unfold(DomTreeUpdater *DTU, LoopInfo *LI,
// Insert the real conditional branch based on the original condition.
StartBlockTerm->eraseFromParent();
- BranchInst::Create(EndBlock, NewBlock, SI->getCondition(), StartBlock);
+ auto *BI =
+ BranchInst::Create(EndBlock, NewBlock, SI->getCondition(), StartBlock);
+ if (!ProfcheckDisableMetadataFixes)
+ BI->setMetadata(LLVMContext::MD_prof,
+ SI->getMetadata(LLVMContext::MD_prof));
DTU->applyUpdates({{DominatorTree::Insert, StartBlock, EndBlock},
{DominatorTree::Insert, StartBlock, NewBlock}});
} else {
@@ -295,7 +302,11 @@ void DFAJumpThreading::unfold(DomTreeUpdater *DTU, LoopInfo *LI,
// (Use)
BranchInst::Create(EndBlock, NewBlockF);
// Insert the real conditional branch based on the original condition.
- BranchInst::Create(EndBlock, NewBlockF, SI->getCondition(), NewBlockT);
+ auto *BI =
+ BranchInst::Create(EndBlock, NewBlockF, SI->getCondition(), NewBlockT);
+ if (!ProfcheckDisableMetadataFixes)
+ BI->setMetadata(LLVMContext::MD_prof,
+ SI->getMetadata(LLVMContext::MD_prof));
DTU->applyUpdates({{DominatorTree::Insert, NewBlockT, NewBlockF},
{DominatorTree::Insert, NewBlockT, EndBlock},
{DominatorTree::Insert, NewBlockF, EndBlock}});
@@ -1195,19 +1206,18 @@ private:
// value for the new predecessor ClonedBB. The value will either be the same
// value from BB or a cloned value.
for (BasicBlock *Succ : BlocksToUpdate) {
- for (auto II = Succ->begin(); PHINode *Phi = dyn_cast<PHINode>(II);
- ++II) {
- Value *Incoming = Phi->getIncomingValueForBlock(BB);
+ for (PHINode &Phi : Succ->phis()) {
+ Value *Incoming = Phi.getIncomingValueForBlock(BB);
if (Incoming) {
if (isa<Constant>(Incoming)) {
- Phi->addIncoming(Incoming, ClonedBB);
+ Phi.addIncoming(Incoming, ClonedBB);
continue;
}
Value *ClonedVal = VMap[Incoming];
if (ClonedVal)
- Phi->addIncoming(ClonedVal, ClonedBB);
+ Phi.addIncoming(ClonedVal, ClonedBB);
else
- Phi->addIncoming(Incoming, ClonedBB);
+ Phi.addIncoming(Incoming, ClonedBB);
}
}
}
@@ -1302,27 +1312,19 @@ private:
void cleanPhiNodes(BasicBlock *BB) {
// If BB is no longer reachable, remove any remaining phi nodes
if (pred_empty(BB)) {
- std::vector<PHINode *> PhiToRemove;
- for (auto II = BB->begin(); PHINode *Phi = dyn_cast<PHINode>(II); ++II) {
- PhiToRemove.push_back(Phi);
- }
- for (PHINode *PN : PhiToRemove) {
- PN->replaceAllUsesWith(PoisonValue::get(PN->getType()));
- PN->eraseFromParent();
+ for (PHINode &PN : make_early_inc_range(BB->phis())) {
+ PN.replaceAllUsesWith(PoisonValue::get(PN.getType()));
+ PN.eraseFromParent();
}
return;
}
// Remove any incoming values that come from an invalid predecessor
- for (auto II = BB->begin(); PHINode *Phi = dyn_cast<PHINode>(II); ++II) {
- std::vector<BasicBlock *> BlocksToRemove;
- for (BasicBlock *IncomingBB : Phi->blocks()) {
- if (!isPredecessor(BB, IncomingBB))
- BlocksToRemove.push_back(IncomingBB);
- }
- for (BasicBlock *BB : BlocksToRemove)
- Phi->removeIncomingValue(BB);
- }
+ for (PHINode &Phi : BB->phis())
+ Phi.removeIncomingValueIf([&](unsigned Index) {
+ BasicBlock *IncomingBB = Phi.getIncomingBlock(Index);
+ return !isPredecessor(BB, IncomingBB);
+ });
}
/// Checks if BB was already cloned for a particular next state value. If it
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index b9b5b58..638952a 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -699,6 +699,7 @@ uint32_t GVNPass::ValueTable::lookupOrAdd(Value *V) {
case Instruction::FPTrunc:
case Instruction::FPExt:
case Instruction::PtrToInt:
+ case Instruction::PtrToAddr:
case Instruction::IntToPtr:
case Instruction::AddrSpaceCast:
case Instruction::BitCast:
diff --git a/llvm/lib/Transforms/Scalar/NewGVN.cpp b/llvm/lib/Transforms/Scalar/NewGVN.cpp
index d6b7633..3c1a8ba 100644
--- a/llvm/lib/Transforms/Scalar/NewGVN.cpp
+++ b/llvm/lib/Transforms/Scalar/NewGVN.cpp
@@ -2066,6 +2066,7 @@ NewGVN::performSymbolicEvaluation(Instruction *I,
case Instruction::FPTrunc:
case Instruction::FPExt:
case Instruction::PtrToInt:
+ case Instruction::PtrToAddr:
case Instruction::IntToPtr:
case Instruction::Select:
case Instruction::ExtractElement:
diff --git a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
index 60e5df0..7ffccf7 100644
--- a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
+++ b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
@@ -355,6 +355,8 @@ void SimplifyCFGPass::printPipeline(
OS << (Options.ForwardSwitchCondToPhi ? "" : "no-") << "forward-switch-cond;";
OS << (Options.ConvertSwitchRangeToICmp ? "" : "no-")
<< "switch-range-to-icmp;";
+ OS << (Options.ConvertSwitchToArithmetic ? "" : "no-")
+ << "switch-to-arithmetic;";
OS << (Options.ConvertSwitchToLookupTable ? "" : "no-")
<< "switch-to-lookup;";
OS << (Options.NeedCanonicalLoop ? "" : "no-") << "keep-loops;";
diff --git a/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp b/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
index 7cc9ff8..0c8d6fa 100644
--- a/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
@@ -45,12 +45,6 @@ STATISTIC(NumInstrsHoisted,
"Number of instructions hoisted into loop preheader");
STATISTIC(NumInstrsDuplicated,
"Number of instructions cloned into loop preheader");
-STATISTIC(NumRotated, "Number of loops rotated");
-
-static cl::opt<bool>
- MultiRotate("loop-rotate-multi", cl::init(false), cl::Hidden,
- cl::desc("Allow loop rotation multiple times in order to reach "
- "a better latch exit"));
// Probability that a rotated loop has zero trip count / is never entered.
static constexpr uint32_t ZeroTripCountWeights[] = {1, 127};
@@ -206,50 +200,6 @@ static bool profitableToRotateLoopExitingLatch(Loop *L) {
return false;
}
-// Check that latch exit is deoptimizing (which means - very unlikely to happen)
-// and there is another exit from the loop which is non-deoptimizing.
-// If we rotate latch to that exit our loop has a better chance of being fully
-// canonical.
-//
-// It can give false positives in some rare cases.
-static bool canRotateDeoptimizingLatchExit(Loop *L) {
- BasicBlock *Latch = L->getLoopLatch();
- assert(Latch && "need latch");
- BranchInst *BI = dyn_cast<BranchInst>(Latch->getTerminator());
- // Need normal exiting latch.
- if (!BI || !BI->isConditional())
- return false;
-
- BasicBlock *Exit = BI->getSuccessor(1);
- if (L->contains(Exit))
- Exit = BI->getSuccessor(0);
-
- // Latch exit is non-deoptimizing, no need to rotate.
- if (!Exit->getPostdominatingDeoptimizeCall())
- return false;
-
- SmallVector<BasicBlock *, 4> Exits;
- L->getUniqueExitBlocks(Exits);
- if (!Exits.empty()) {
- // There is at least one non-deoptimizing exit.
- //
- // Note, that BasicBlock::getPostdominatingDeoptimizeCall is not exact,
- // as it can conservatively return false for deoptimizing exits with
- // complex enough control flow down to deoptimize call.
- //
- // That means here we can report success for a case where
- // all exits are deoptimizing but one of them has complex enough
- // control flow (e.g. with loops).
- //
- // That should be a very rare case and false positives for this function
- // have compile-time effect only.
- return any_of(Exits, [](const BasicBlock *BB) {
- return !BB->getPostdominatingDeoptimizeCall();
- });
- }
- return false;
-}
-
static void updateBranchWeights(BranchInst &PreHeaderBI, BranchInst &LoopBI,
bool HasConditionalPreHeader,
bool SuccsSwapped) {
@@ -387,506 +337,489 @@ static void updateBranchWeights(BranchInst &PreHeaderBI, BranchInst &LoopBI,
/// rotation. LoopRotate should be repeatable and converge to a canonical
/// form. This property is satisfied because simplifying the loop latch can only
/// happen once across multiple invocations of the LoopRotate pass.
-///
-/// If -loop-rotate-multi is enabled we can do multiple rotations in one go
-/// so to reach a suitable (non-deoptimizing) exit.
bool LoopRotate::rotateLoop(Loop *L, bool SimplifiedLatch) {
// If the loop has only one block then there is not much to rotate.
if (L->getBlocks().size() == 1)
return false;
bool Rotated = false;
- do {
- BasicBlock *OrigHeader = L->getHeader();
- BasicBlock *OrigLatch = L->getLoopLatch();
-
- BranchInst *BI = dyn_cast<BranchInst>(OrigHeader->getTerminator());
- if (!BI || BI->isUnconditional())
- return Rotated;
-
- // If the loop header is not one of the loop exiting blocks then
- // either this loop is already rotated or it is not
- // suitable for loop rotation transformations.
- if (!L->isLoopExiting(OrigHeader))
+ BasicBlock *OrigHeader = L->getHeader();
+ BasicBlock *OrigLatch = L->getLoopLatch();
+
+ BranchInst *BI = dyn_cast<BranchInst>(OrigHeader->getTerminator());
+ if (!BI || BI->isUnconditional())
+ return Rotated;
+
+ // If the loop header is not one of the loop exiting blocks then
+ // either this loop is already rotated or it is not
+ // suitable for loop rotation transformations.
+ if (!L->isLoopExiting(OrigHeader))
+ return Rotated;
+
+ // If the loop latch already contains a branch that leaves the loop then the
+ // loop is already rotated.
+ if (!OrigLatch)
+ return Rotated;
+
+ // Rotate if the loop latch was just simplified. Or if it makes the loop exit
+ // count computable. Or if we think it will be profitable.
+ if (L->isLoopExiting(OrigLatch) && !SimplifiedLatch && IsUtilMode == false &&
+ !profitableToRotateLoopExitingLatch(L))
+ return Rotated;
+
+ // Check size of original header and reject loop if it is very big or we can't
+ // duplicate blocks inside it.
+ {
+ SmallPtrSet<const Value *, 32> EphValues;
+ CodeMetrics::collectEphemeralValues(L, AC, EphValues);
+
+ CodeMetrics Metrics;
+ Metrics.analyzeBasicBlock(OrigHeader, *TTI, EphValues, PrepareForLTO);
+ if (Metrics.notDuplicatable) {
+ LLVM_DEBUG(
+ dbgs() << "LoopRotation: NOT rotating - contains non-duplicatable"
+ << " instructions: ";
+ L->dump());
return Rotated;
-
- // If the loop latch already contains a branch that leaves the loop then the
- // loop is already rotated.
- if (!OrigLatch)
+ }
+ if (Metrics.Convergence != ConvergenceKind::None) {
+ LLVM_DEBUG(dbgs() << "LoopRotation: NOT rotating - contains convergent "
+ "instructions: ";
+ L->dump());
return Rotated;
-
- // Rotate if either the loop latch does *not* exit the loop, or if the loop
- // latch was just simplified. Or if we think it will be profitable.
- if (L->isLoopExiting(OrigLatch) && !SimplifiedLatch && IsUtilMode == false &&
- !profitableToRotateLoopExitingLatch(L) &&
- !canRotateDeoptimizingLatchExit(L))
+ }
+ if (!Metrics.NumInsts.isValid()) {
+ LLVM_DEBUG(dbgs() << "LoopRotation: NOT rotating - contains instructions"
+ " with invalid cost: ";
+ L->dump());
return Rotated;
-
- // Check size of original header and reject loop if it is very big or we can't
- // duplicate blocks inside it.
- {
- SmallPtrSet<const Value *, 32> EphValues;
- CodeMetrics::collectEphemeralValues(L, AC, EphValues);
-
- CodeMetrics Metrics;
- Metrics.analyzeBasicBlock(OrigHeader, *TTI, EphValues, PrepareForLTO);
- if (Metrics.notDuplicatable) {
- LLVM_DEBUG(
- dbgs() << "LoopRotation: NOT rotating - contains non-duplicatable"
- << " instructions: ";
- L->dump());
- return Rotated;
- }
- if (Metrics.Convergence != ConvergenceKind::None) {
- LLVM_DEBUG(dbgs() << "LoopRotation: NOT rotating - contains convergent "
- "instructions: ";
- L->dump());
- return Rotated;
- }
- if (!Metrics.NumInsts.isValid()) {
- LLVM_DEBUG(dbgs() << "LoopRotation: NOT rotating - contains instructions"
- " with invalid cost: ";
- L->dump());
- return Rotated;
- }
- if (Metrics.NumInsts > MaxHeaderSize) {
- LLVM_DEBUG(dbgs() << "LoopRotation: NOT rotating - contains "
- << Metrics.NumInsts
- << " instructions, which is more than the threshold ("
- << MaxHeaderSize << " instructions): ";
- L->dump());
- ++NumNotRotatedDueToHeaderSize;
- return Rotated;
- }
-
- // When preparing for LTO, avoid rotating loops with calls that could be
- // inlined during the LTO stage.
- if (PrepareForLTO && Metrics.NumInlineCandidates > 0)
- return Rotated;
}
-
- // Now, this loop is suitable for rotation.
- BasicBlock *OrigPreheader = L->getLoopPreheader();
-
- // If the loop could not be converted to canonical form, it must have an
- // indirectbr in it, just give up.
- if (!OrigPreheader || !L->hasDedicatedExits())
+ if (Metrics.NumInsts > MaxHeaderSize) {
+ LLVM_DEBUG(dbgs() << "LoopRotation: NOT rotating - contains "
+ << Metrics.NumInsts
+ << " instructions, which is more than the threshold ("
+ << MaxHeaderSize << " instructions): ";
+ L->dump());
+ ++NumNotRotatedDueToHeaderSize;
return Rotated;
-
- // Anything ScalarEvolution may know about this loop or the PHI nodes
- // in its header will soon be invalidated. We should also invalidate
- // all outer loops because insertion and deletion of blocks that happens
- // during the rotation may violate invariants related to backedge taken
- // infos in them.
- if (SE) {
- SE->forgetTopmostLoop(L);
- // We may hoist some instructions out of loop. In case if they were cached
- // as "loop variant" or "loop computable", these caches must be dropped.
- // We also may fold basic blocks, so cached block dispositions also need
- // to be dropped.
- SE->forgetBlockAndLoopDispositions();
}
- LLVM_DEBUG(dbgs() << "LoopRotation: rotating "; L->dump());
- if (MSSAU && VerifyMemorySSA)
- MSSAU->getMemorySSA()->verifyMemorySSA();
-
- // Find new Loop header. NewHeader is a Header's one and only successor
- // that is inside loop. Header's other successor is outside the
- // loop. Otherwise loop is not suitable for rotation.
- BasicBlock *Exit = BI->getSuccessor(0);
- BasicBlock *NewHeader = BI->getSuccessor(1);
- bool BISuccsSwapped = L->contains(Exit);
- if (BISuccsSwapped)
- std::swap(Exit, NewHeader);
- assert(NewHeader && "Unable to determine new loop header");
- assert(L->contains(NewHeader) && !L->contains(Exit) &&
- "Unable to determine loop header and exit blocks");
-
- // This code assumes that the new header has exactly one predecessor.
- // Remove any single-entry PHI nodes in it.
- assert(NewHeader->getSinglePredecessor() &&
- "New header doesn't have one pred!");
- FoldSingleEntryPHINodes(NewHeader);
-
- // Begin by walking OrigHeader and populating ValueMap with an entry for
- // each Instruction.
- BasicBlock::iterator I = OrigHeader->begin(), E = OrigHeader->end();
- ValueToValueMapTy ValueMap, ValueMapMSSA;
-
- // For PHI nodes, the value available in OldPreHeader is just the
- // incoming value from OldPreHeader.
- for (; PHINode *PN = dyn_cast<PHINode>(I); ++I)
- InsertNewValueIntoMap(ValueMap, PN,
- PN->getIncomingValueForBlock(OrigPreheader));
-
- // For the rest of the instructions, either hoist to the OrigPreheader if
- // possible or create a clone in the OldPreHeader if not.
- Instruction *LoopEntryBranch = OrigPreheader->getTerminator();
-
- // Record all debug records preceding LoopEntryBranch to avoid
- // duplication.
- using DbgHash =
- std::pair<std::pair<hash_code, DILocalVariable *>, DIExpression *>;
- auto makeHash = [](const DbgVariableRecord *D) -> DbgHash {
- auto VarLocOps = D->location_ops();
- return {{hash_combine_range(VarLocOps), D->getVariable()},
- D->getExpression()};
- };
-
- SmallDenseSet<DbgHash, 8> DbgRecords;
- // Build DbgVariableRecord hashes for DbgVariableRecords attached to the
- // terminator.
- for (const DbgVariableRecord &DVR :
- filterDbgVars(OrigPreheader->getTerminator()->getDbgRecordRange()))
- DbgRecords.insert(makeHash(&DVR));
-
- // Remember the local noalias scope declarations in the header. After the
- // rotation, they must be duplicated and the scope must be cloned. This
- // avoids unwanted interaction across iterations.
- SmallVector<NoAliasScopeDeclInst *, 6> NoAliasDeclInstructions;
- for (Instruction &I : *OrigHeader)
- if (auto *Decl = dyn_cast<NoAliasScopeDeclInst>(&I))
- NoAliasDeclInstructions.push_back(Decl);
-
- Module *M = OrigHeader->getModule();
-
- // Track the next DbgRecord to clone. If we have a sequence where an
- // instruction is hoisted instead of being cloned:
- // DbgRecord blah
- // %foo = add i32 0, 0
- // DbgRecord xyzzy
- // %bar = call i32 @foobar()
- // where %foo is hoisted, then the DbgRecord "blah" will be seen twice, once
- // attached to %foo, then when %foo his hoisted it will "fall down" onto the
- // function call:
- // DbgRecord blah
- // DbgRecord xyzzy
- // %bar = call i32 @foobar()
- // causing it to appear attached to the call too.
- //
- // To avoid this, cloneDebugInfoFrom takes an optional "start cloning from
- // here" position to account for this behaviour. We point it at any
- // DbgRecords on the next instruction, here labelled xyzzy, before we hoist
- // %foo. Later, we only only clone DbgRecords from that position (xyzzy)
- // onwards, which avoids cloning DbgRecord "blah" multiple times. (Stored as
- // a range because it gives us a natural way of testing whether
- // there were DbgRecords on the next instruction before we hoisted things).
- iterator_range<DbgRecord::self_iterator> NextDbgInsts =
- (I != E) ? I->getDbgRecordRange() : DbgMarker::getEmptyDbgRecordRange();
-
- while (I != E) {
- Instruction *Inst = &*I++;
-
- // If the instruction's operands are invariant and it doesn't read or write
- // memory, then it is safe to hoist. Doing this doesn't change the order of
- // execution in the preheader, but does prevent the instruction from
- // executing in each iteration of the loop. This means it is safe to hoist
- // something that might trap, but isn't safe to hoist something that reads
- // memory (without proving that the loop doesn't write).
- if (L->hasLoopInvariantOperands(Inst) && !Inst->mayReadFromMemory() &&
- !Inst->mayWriteToMemory() && !Inst->isTerminator() &&
- !isa<AllocaInst>(Inst) &&
- // It is not safe to hoist the value of these instructions in
- // coroutines, as the addresses of otherwise eligible variables (e.g.
- // thread-local variables and errno) may change if the coroutine is
- // resumed in a different thread.Therefore, we disable this
- // optimization for correctness. However, this may block other correct
- // optimizations.
- // FIXME: This should be reverted once we have a better model for
- // memory access in coroutines.
- !Inst->getFunction()->isPresplitCoroutine()) {
-
- if (!NextDbgInsts.empty()) {
- auto DbgValueRange =
- LoopEntryBranch->cloneDebugInfoFrom(Inst, NextDbgInsts.begin());
- RemapDbgRecordRange(M, DbgValueRange, ValueMap,
- RF_NoModuleLevelChanges | RF_IgnoreMissingLocals);
- // Erase anything we've seen before.
- for (DbgVariableRecord &DVR :
- make_early_inc_range(filterDbgVars(DbgValueRange)))
- if (DbgRecords.count(makeHash(&DVR)))
- DVR.eraseFromParent();
- }
-
- NextDbgInsts = I->getDbgRecordRange();
-
- Inst->moveBefore(LoopEntryBranch->getIterator());
+ // When preparing for LTO, avoid rotating loops with calls that could be
+ // inlined during the LTO stage.
+ if (PrepareForLTO && Metrics.NumInlineCandidates > 0)
+ return Rotated;
+ }
- ++NumInstrsHoisted;
- continue;
- }
+ // Now, this loop is suitable for rotation.
+ BasicBlock *OrigPreheader = L->getLoopPreheader();
+
+ // If the loop could not be converted to canonical form, it must have an
+ // indirectbr in it, just give up.
+ if (!OrigPreheader || !L->hasDedicatedExits())
+ return Rotated;
+
+ // Anything ScalarEvolution may know about this loop or the PHI nodes
+ // in its header will soon be invalidated. We should also invalidate
+ // all outer loops because insertion and deletion of blocks that happens
+ // during the rotation may violate invariants related to backedge taken
+ // infos in them.
+ if (SE) {
+ SE->forgetTopmostLoop(L);
+ // We may hoist some instructions out of loop. In case if they were cached
+ // as "loop variant" or "loop computable", these caches must be dropped.
+ // We also may fold basic blocks, so cached block dispositions also need
+ // to be dropped.
+ SE->forgetBlockAndLoopDispositions();
+ }
- // Otherwise, create a duplicate of the instruction.
- Instruction *C = Inst->clone();
- if (const DebugLoc &DL = C->getDebugLoc())
- mapAtomInstance(DL, ValueMap);
+ LLVM_DEBUG(dbgs() << "LoopRotation: rotating "; L->dump());
+ if (MSSAU && VerifyMemorySSA)
+ MSSAU->getMemorySSA()->verifyMemorySSA();
- C->insertBefore(LoopEntryBranch->getIterator());
+ // Find new Loop header. NewHeader is a Header's one and only successor
+ // that is inside loop. Header's other successor is outside the
+ // loop. Otherwise loop is not suitable for rotation.
+ BasicBlock *Exit = BI->getSuccessor(0);
+ BasicBlock *NewHeader = BI->getSuccessor(1);
+ bool BISuccsSwapped = L->contains(Exit);
+ if (BISuccsSwapped)
+ std::swap(Exit, NewHeader);
+ assert(NewHeader && "Unable to determine new loop header");
+ assert(L->contains(NewHeader) && !L->contains(Exit) &&
+ "Unable to determine loop header and exit blocks");
+
+ // This code assumes that the new header has exactly one predecessor.
+ // Remove any single-entry PHI nodes in it.
+ assert(NewHeader->getSinglePredecessor() &&
+ "New header doesn't have one pred!");
+ FoldSingleEntryPHINodes(NewHeader);
+
+ // Begin by walking OrigHeader and populating ValueMap with an entry for
+ // each Instruction.
+ BasicBlock::iterator I = OrigHeader->begin(), E = OrigHeader->end();
+ ValueToValueMapTy ValueMap, ValueMapMSSA;
+
+ // For PHI nodes, the value available in OldPreHeader is just the
+ // incoming value from OldPreHeader.
+ for (; PHINode *PN = dyn_cast<PHINode>(I); ++I)
+ InsertNewValueIntoMap(ValueMap, PN,
+ PN->getIncomingValueForBlock(OrigPreheader));
+
+ // For the rest of the instructions, either hoist to the OrigPreheader if
+ // possible or create a clone in the OldPreHeader if not.
+ Instruction *LoopEntryBranch = OrigPreheader->getTerminator();
+
+ // Record all debug records preceding LoopEntryBranch to avoid
+ // duplication.
+ using DbgHash =
+ std::pair<std::pair<hash_code, DILocalVariable *>, DIExpression *>;
+ auto makeHash = [](const DbgVariableRecord *D) -> DbgHash {
+ auto VarLocOps = D->location_ops();
+ return {{hash_combine_range(VarLocOps), D->getVariable()},
+ D->getExpression()};
+ };
- ++NumInstrsDuplicated;
+ SmallDenseSet<DbgHash, 8> DbgRecords;
+ // Build DbgVariableRecord hashes for DbgVariableRecords attached to the
+ // terminator.
+ for (const DbgVariableRecord &DVR :
+ filterDbgVars(OrigPreheader->getTerminator()->getDbgRecordRange()))
+ DbgRecords.insert(makeHash(&DVR));
+
+ // Remember the local noalias scope declarations in the header. After the
+ // rotation, they must be duplicated and the scope must be cloned. This
+ // avoids unwanted interaction across iterations.
+ SmallVector<NoAliasScopeDeclInst *, 6> NoAliasDeclInstructions;
+ for (Instruction &I : *OrigHeader)
+ if (auto *Decl = dyn_cast<NoAliasScopeDeclInst>(&I))
+ NoAliasDeclInstructions.push_back(Decl);
+
+ Module *M = OrigHeader->getModule();
+
+ // Track the next DbgRecord to clone. If we have a sequence where an
+ // instruction is hoisted instead of being cloned:
+ // DbgRecord blah
+ // %foo = add i32 0, 0
+ // DbgRecord xyzzy
+ // %bar = call i32 @foobar()
+ // where %foo is hoisted, then the DbgRecord "blah" will be seen twice, once
+ // attached to %foo, then when %foo his hoisted it will "fall down" onto the
+ // function call:
+ // DbgRecord blah
+ // DbgRecord xyzzy
+ // %bar = call i32 @foobar()
+ // causing it to appear attached to the call too.
+ //
+ // To avoid this, cloneDebugInfoFrom takes an optional "start cloning from
+ // here" position to account for this behaviour. We point it at any
+ // DbgRecords on the next instruction, here labelled xyzzy, before we hoist
+ // %foo. Later, we only only clone DbgRecords from that position (xyzzy)
+ // onwards, which avoids cloning DbgRecord "blah" multiple times. (Stored as
+ // a range because it gives us a natural way of testing whether
+ // there were DbgRecords on the next instruction before we hoisted things).
+ iterator_range<DbgRecord::self_iterator> NextDbgInsts =
+ (I != E) ? I->getDbgRecordRange() : DbgMarker::getEmptyDbgRecordRange();
+
+ while (I != E) {
+ Instruction *Inst = &*I++;
+
+ // If the instruction's operands are invariant and it doesn't read or write
+ // memory, then it is safe to hoist. Doing this doesn't change the order of
+ // execution in the preheader, but does prevent the instruction from
+ // executing in each iteration of the loop. This means it is safe to hoist
+ // something that might trap, but isn't safe to hoist something that reads
+ // memory (without proving that the loop doesn't write).
+ if (L->hasLoopInvariantOperands(Inst) && !Inst->mayReadFromMemory() &&
+ !Inst->mayWriteToMemory() && !Inst->isTerminator() &&
+ !isa<AllocaInst>(Inst) &&
+ // It is not safe to hoist the value of these instructions in
+ // coroutines, as the addresses of otherwise eligible variables (e.g.
+ // thread-local variables and errno) may change if the coroutine is
+ // resumed in a different thread.Therefore, we disable this
+ // optimization for correctness. However, this may block other correct
+ // optimizations.
+ // FIXME: This should be reverted once we have a better model for
+ // memory access in coroutines.
+ !Inst->getFunction()->isPresplitCoroutine()) {
if (!NextDbgInsts.empty()) {
- auto Range = C->cloneDebugInfoFrom(Inst, NextDbgInsts.begin());
- RemapDbgRecordRange(M, Range, ValueMap,
+ auto DbgValueRange =
+ LoopEntryBranch->cloneDebugInfoFrom(Inst, NextDbgInsts.begin());
+ RemapDbgRecordRange(M, DbgValueRange, ValueMap,
RF_NoModuleLevelChanges | RF_IgnoreMissingLocals);
- NextDbgInsts = DbgMarker::getEmptyDbgRecordRange();
// Erase anything we've seen before.
for (DbgVariableRecord &DVR :
- make_early_inc_range(filterDbgVars(Range)))
+ make_early_inc_range(filterDbgVars(DbgValueRange)))
if (DbgRecords.count(makeHash(&DVR)))
DVR.eraseFromParent();
}
- // Eagerly remap the operands of the instruction.
- RemapInstruction(C, ValueMap,
- RF_NoModuleLevelChanges | RF_IgnoreMissingLocals);
-
- // With the operands remapped, see if the instruction constant folds or is
- // otherwise simplifyable. This commonly occurs because the entry from PHI
- // nodes allows icmps and other instructions to fold.
- Value *V = simplifyInstruction(C, SQ);
- if (V && LI->replacementPreservesLCSSAForm(C, V)) {
- // If so, then delete the temporary instruction and stick the folded value
- // in the map.
- InsertNewValueIntoMap(ValueMap, Inst, V);
- if (!C->mayHaveSideEffects()) {
- C->eraseFromParent();
- C = nullptr;
- }
- } else {
- InsertNewValueIntoMap(ValueMap, Inst, C);
- }
- if (C) {
- // Otherwise, stick the new instruction into the new block!
- C->setName(Inst->getName());
-
- if (auto *II = dyn_cast<AssumeInst>(C))
- AC->registerAssumption(II);
- // MemorySSA cares whether the cloned instruction was inserted or not, and
- // not whether it can be remapped to a simplified value.
- if (MSSAU)
- InsertNewValueIntoMap(ValueMapMSSA, Inst, C);
- }
- }
+ NextDbgInsts = I->getDbgRecordRange();
- if (!NoAliasDeclInstructions.empty()) {
- // There are noalias scope declarations:
- // (general):
- // Original: OrigPre { OrigHeader NewHeader ... Latch }
- // after: (OrigPre+OrigHeader') { NewHeader ... Latch OrigHeader }
- //
- // with D: llvm.experimental.noalias.scope.decl,
- // U: !noalias or !alias.scope depending on D
- // ... { D U1 U2 } can transform into:
- // (0) : ... { D U1 U2 } // no relevant rotation for this part
- // (1) : ... D' { U1 U2 D } // D is part of OrigHeader
- // (2) : ... D' U1' { U2 D U1 } // D, U1 are part of OrigHeader
- //
- // We now want to transform:
- // (1) -> : ... D' { D U1 U2 D'' }
- // (2) -> : ... D' U1' { D U2 D'' U1'' }
- // D: original llvm.experimental.noalias.scope.decl
- // D', U1': duplicate with replaced scopes
- // D'', U1'': different duplicate with replaced scopes
- // This ensures a safe fallback to 'may_alias' introduced by the rotate,
- // as U1'' and U1' scopes will not be compatible wrt to the local restrict
-
- // Clone the llvm.experimental.noalias.decl again for the NewHeader.
- BasicBlock::iterator NewHeaderInsertionPoint =
- NewHeader->getFirstNonPHIIt();
- for (NoAliasScopeDeclInst *NAD : NoAliasDeclInstructions) {
- LLVM_DEBUG(dbgs() << " Cloning llvm.experimental.noalias.scope.decl:"
- << *NAD << "\n");
- Instruction *NewNAD = NAD->clone();
- NewNAD->insertBefore(*NewHeader, NewHeaderInsertionPoint);
- }
+ Inst->moveBefore(LoopEntryBranch->getIterator());
- // Scopes must now be duplicated, once for OrigHeader and once for
- // OrigPreHeader'.
- {
- auto &Context = NewHeader->getContext();
-
- SmallVector<MDNode *, 8> NoAliasDeclScopes;
- for (NoAliasScopeDeclInst *NAD : NoAliasDeclInstructions)
- NoAliasDeclScopes.push_back(NAD->getScopeList());
-
- LLVM_DEBUG(dbgs() << " Updating OrigHeader scopes\n");
- cloneAndAdaptNoAliasScopes(NoAliasDeclScopes, {OrigHeader}, Context,
- "h.rot");
- LLVM_DEBUG(OrigHeader->dump());
-
- // Keep the compile time impact low by only adapting the inserted block
- // of instructions in the OrigPreHeader. This might result in slightly
- // more aliasing between these instructions and those that were already
- // present, but it will be much faster when the original PreHeader is
- // large.
- LLVM_DEBUG(dbgs() << " Updating part of OrigPreheader scopes\n");
- auto *FirstDecl =
- cast<Instruction>(ValueMap[*NoAliasDeclInstructions.begin()]);
- auto *LastInst = &OrigPreheader->back();
- cloneAndAdaptNoAliasScopes(NoAliasDeclScopes, FirstDecl, LastInst,
- Context, "pre.rot");
- LLVM_DEBUG(OrigPreheader->dump());
-
- LLVM_DEBUG(dbgs() << " Updated NewHeader:\n");
- LLVM_DEBUG(NewHeader->dump());
- }
+ ++NumInstrsHoisted;
+ continue;
}
- // Along with all the other instructions, we just cloned OrigHeader's
- // terminator into OrigPreHeader. Fix up the PHI nodes in each of OrigHeader's
- // successors by duplicating their incoming values for OrigHeader.
- for (BasicBlock *SuccBB : successors(OrigHeader))
- for (BasicBlock::iterator BI = SuccBB->begin();
- PHINode *PN = dyn_cast<PHINode>(BI); ++BI)
- PN->addIncoming(PN->getIncomingValueForBlock(OrigHeader), OrigPreheader);
-
- // Now that OrigPreHeader has a clone of OrigHeader's terminator, remove
- // OrigPreHeader's old terminator (the original branch into the loop), and
- // remove the corresponding incoming values from the PHI nodes in OrigHeader.
- LoopEntryBranch->eraseFromParent();
- OrigPreheader->flushTerminatorDbgRecords();
-
- // Update MemorySSA before the rewrite call below changes the 1:1
- // instruction:cloned_instruction_or_value mapping.
- if (MSSAU) {
- InsertNewValueIntoMap(ValueMapMSSA, OrigHeader, OrigPreheader);
- MSSAU->updateForClonedBlockIntoPred(OrigHeader, OrigPreheader,
- ValueMapMSSA);
- }
+ // Otherwise, create a duplicate of the instruction.
+ Instruction *C = Inst->clone();
+ if (const DebugLoc &DL = C->getDebugLoc())
+ mapAtomInstance(DL, ValueMap);
- SmallVector<PHINode*, 2> InsertedPHIs;
- // If there were any uses of instructions in the duplicated block outside the
- // loop, update them, inserting PHI nodes as required
- RewriteUsesOfClonedInstructions(OrigHeader, OrigPreheader, ValueMap, SE,
- &InsertedPHIs);
-
- // Attach debug records to the new phis if that phi uses a value that
- // previously had debug metadata attached. This keeps the debug info
- // up-to-date in the loop body.
- if (!InsertedPHIs.empty())
- insertDebugValuesForPHIs(OrigHeader, InsertedPHIs);
-
- // NewHeader is now the header of the loop.
- L->moveToHeader(NewHeader);
- assert(L->getHeader() == NewHeader && "Latch block is our new header");
-
- // Inform DT about changes to the CFG.
- if (DT) {
- // The OrigPreheader branches to the NewHeader and Exit now. Then, inform
- // the DT about the removed edge to the OrigHeader (that got removed).
- SmallVector<DominatorTree::UpdateType, 3> Updates = {
- {DominatorTree::Insert, OrigPreheader, Exit},
- {DominatorTree::Insert, OrigPreheader, NewHeader},
- {DominatorTree::Delete, OrigPreheader, OrigHeader}};
-
- if (MSSAU) {
- MSSAU->applyUpdates(Updates, *DT, /*UpdateDT=*/true);
- if (VerifyMemorySSA)
- MSSAU->getMemorySSA()->verifyMemorySSA();
- } else {
- DT->applyUpdates(Updates);
- }
- }
+ C->insertBefore(LoopEntryBranch->getIterator());
- // At this point, we've finished our major CFG changes. As part of cloning
- // the loop into the preheader we've simplified instructions and the
- // duplicated conditional branch may now be branching on a constant. If it is
- // branching on a constant and if that constant means that we enter the loop,
- // then we fold away the cond branch to an uncond branch. This simplifies the
- // loop in cases important for nested loops, and it also means we don't have
- // to split as many edges.
- BranchInst *PHBI = cast<BranchInst>(OrigPreheader->getTerminator());
- assert(PHBI->isConditional() && "Should be clone of BI condbr!");
- const Value *Cond = PHBI->getCondition();
- const bool HasConditionalPreHeader =
- !isa<ConstantInt>(Cond) ||
- PHBI->getSuccessor(cast<ConstantInt>(Cond)->isZero()) != NewHeader;
-
- updateBranchWeights(*PHBI, *BI, HasConditionalPreHeader, BISuccsSwapped);
+ ++NumInstrsDuplicated;
- if (HasConditionalPreHeader) {
- // The conditional branch can't be folded, handle the general case.
- // Split edges as necessary to preserve LoopSimplify form.
-
- // Right now OrigPreHeader has two successors, NewHeader and ExitBlock, and
- // thus is not a preheader anymore.
- // Split the edge to form a real preheader.
- BasicBlock *NewPH = SplitCriticalEdge(
- OrigPreheader, NewHeader,
- CriticalEdgeSplittingOptions(DT, LI, MSSAU).setPreserveLCSSA());
- NewPH->setName(NewHeader->getName() + ".lr.ph");
-
- // Preserve canonical loop form, which means that 'Exit' should have only
- // one predecessor. Note that Exit could be an exit block for multiple
- // nested loops, causing both of the edges to now be critical and need to
- // be split.
- SmallVector<BasicBlock *, 4> ExitPreds(predecessors(Exit));
- bool SplitLatchEdge = false;
- for (BasicBlock *ExitPred : ExitPreds) {
- // We only need to split loop exit edges.
- Loop *PredLoop = LI->getLoopFor(ExitPred);
- if (!PredLoop || PredLoop->contains(Exit) ||
- isa<IndirectBrInst>(ExitPred->getTerminator()))
- continue;
- SplitLatchEdge |= L->getLoopLatch() == ExitPred;
- BasicBlock *ExitSplit = SplitCriticalEdge(
- ExitPred, Exit,
- CriticalEdgeSplittingOptions(DT, LI, MSSAU).setPreserveLCSSA());
- ExitSplit->moveBefore(Exit);
+ if (!NextDbgInsts.empty()) {
+ auto Range = C->cloneDebugInfoFrom(Inst, NextDbgInsts.begin());
+ RemapDbgRecordRange(M, Range, ValueMap,
+ RF_NoModuleLevelChanges | RF_IgnoreMissingLocals);
+ NextDbgInsts = DbgMarker::getEmptyDbgRecordRange();
+ // Erase anything we've seen before.
+ for (DbgVariableRecord &DVR : make_early_inc_range(filterDbgVars(Range)))
+ if (DbgRecords.count(makeHash(&DVR)))
+ DVR.eraseFromParent();
+ }
+
+ // Eagerly remap the operands of the instruction.
+ RemapInstruction(C, ValueMap,
+ RF_NoModuleLevelChanges | RF_IgnoreMissingLocals);
+
+ // With the operands remapped, see if the instruction constant folds or is
+ // otherwise simplifyable. This commonly occurs because the entry from PHI
+ // nodes allows icmps and other instructions to fold.
+ Value *V = simplifyInstruction(C, SQ);
+ if (V && LI->replacementPreservesLCSSAForm(C, V)) {
+ // If so, then delete the temporary instruction and stick the folded value
+ // in the map.
+ InsertNewValueIntoMap(ValueMap, Inst, V);
+ if (!C->mayHaveSideEffects()) {
+ C->eraseFromParent();
+ C = nullptr;
}
- assert(SplitLatchEdge &&
- "Despite splitting all preds, failed to split latch exit?");
- (void)SplitLatchEdge;
} else {
- // We can fold the conditional branch in the preheader, this makes things
- // simpler. The first step is to remove the extra edge to the Exit block.
- Exit->removePredecessor(OrigPreheader, true /*preserve LCSSA*/);
- BranchInst *NewBI = BranchInst::Create(NewHeader, PHBI->getIterator());
- NewBI->setDebugLoc(PHBI->getDebugLoc());
- PHBI->eraseFromParent();
+ InsertNewValueIntoMap(ValueMap, Inst, C);
+ }
+ if (C) {
+ // Otherwise, stick the new instruction into the new block!
+ C->setName(Inst->getName());
+
+ if (auto *II = dyn_cast<AssumeInst>(C))
+ AC->registerAssumption(II);
+ // MemorySSA cares whether the cloned instruction was inserted or not, and
+ // not whether it can be remapped to a simplified value.
+ if (MSSAU)
+ InsertNewValueIntoMap(ValueMapMSSA, Inst, C);
+ }
+ }
- // With our CFG finalized, update DomTree if it is available.
- if (DT) DT->deleteEdge(OrigPreheader, Exit);
+ if (!NoAliasDeclInstructions.empty()) {
+ // There are noalias scope declarations:
+ // (general):
+ // Original: OrigPre { OrigHeader NewHeader ... Latch }
+ // after: (OrigPre+OrigHeader') { NewHeader ... Latch OrigHeader }
+ //
+ // with D: llvm.experimental.noalias.scope.decl,
+ // U: !noalias or !alias.scope depending on D
+ // ... { D U1 U2 } can transform into:
+ // (0) : ... { D U1 U2 } // no relevant rotation for this part
+ // (1) : ... D' { U1 U2 D } // D is part of OrigHeader
+ // (2) : ... D' U1' { U2 D U1 } // D, U1 are part of OrigHeader
+ //
+ // We now want to transform:
+ // (1) -> : ... D' { D U1 U2 D'' }
+ // (2) -> : ... D' U1' { D U2 D'' U1'' }
+ // D: original llvm.experimental.noalias.scope.decl
+ // D', U1': duplicate with replaced scopes
+ // D'', U1'': different duplicate with replaced scopes
+ // This ensures a safe fallback to 'may_alias' introduced by the rotate,
+ // as U1'' and U1' scopes will not be compatible wrt to the local restrict
+
+ // Clone the llvm.experimental.noalias.decl again for the NewHeader.
+ BasicBlock::iterator NewHeaderInsertionPoint =
+ NewHeader->getFirstNonPHIIt();
+ for (NoAliasScopeDeclInst *NAD : NoAliasDeclInstructions) {
+ LLVM_DEBUG(dbgs() << " Cloning llvm.experimental.noalias.scope.decl:"
+ << *NAD << "\n");
+ Instruction *NewNAD = NAD->clone();
+ NewNAD->insertBefore(*NewHeader, NewHeaderInsertionPoint);
+ }
- // Update MSSA too, if available.
- if (MSSAU)
- MSSAU->removeEdge(OrigPreheader, Exit);
+ // Scopes must now be duplicated, once for OrigHeader and once for
+ // OrigPreHeader'.
+ {
+ auto &Context = NewHeader->getContext();
+
+ SmallVector<MDNode *, 8> NoAliasDeclScopes;
+ for (NoAliasScopeDeclInst *NAD : NoAliasDeclInstructions)
+ NoAliasDeclScopes.push_back(NAD->getScopeList());
+
+ LLVM_DEBUG(dbgs() << " Updating OrigHeader scopes\n");
+ cloneAndAdaptNoAliasScopes(NoAliasDeclScopes, {OrigHeader}, Context,
+ "h.rot");
+ LLVM_DEBUG(OrigHeader->dump());
+
+ // Keep the compile time impact low by only adapting the inserted block
+ // of instructions in the OrigPreHeader. This might result in slightly
+ // more aliasing between these instructions and those that were already
+ // present, but it will be much faster when the original PreHeader is
+ // large.
+ LLVM_DEBUG(dbgs() << " Updating part of OrigPreheader scopes\n");
+ auto *FirstDecl =
+ cast<Instruction>(ValueMap[*NoAliasDeclInstructions.begin()]);
+ auto *LastInst = &OrigPreheader->back();
+ cloneAndAdaptNoAliasScopes(NoAliasDeclScopes, FirstDecl, LastInst,
+ Context, "pre.rot");
+ LLVM_DEBUG(OrigPreheader->dump());
+
+ LLVM_DEBUG(dbgs() << " Updated NewHeader:\n");
+ LLVM_DEBUG(NewHeader->dump());
}
+ }
- assert(L->getLoopPreheader() && "Invalid loop preheader after loop rotation");
- assert(L->getLoopLatch() && "Invalid loop latch after loop rotation");
+ // Along with all the other instructions, we just cloned OrigHeader's
+ // terminator into OrigPreHeader. Fix up the PHI nodes in each of OrigHeader's
+ // successors by duplicating their incoming values for OrigHeader.
+ for (BasicBlock *SuccBB : successors(OrigHeader))
+ for (BasicBlock::iterator BI = SuccBB->begin();
+ PHINode *PN = dyn_cast<PHINode>(BI); ++BI)
+ PN->addIncoming(PN->getIncomingValueForBlock(OrigHeader), OrigPreheader);
+
+ // Now that OrigPreHeader has a clone of OrigHeader's terminator, remove
+ // OrigPreHeader's old terminator (the original branch into the loop), and
+ // remove the corresponding incoming values from the PHI nodes in OrigHeader.
+ LoopEntryBranch->eraseFromParent();
+ OrigPreheader->flushTerminatorDbgRecords();
+
+ // Update MemorySSA before the rewrite call below changes the 1:1
+ // instruction:cloned_instruction_or_value mapping.
+ if (MSSAU) {
+ InsertNewValueIntoMap(ValueMapMSSA, OrigHeader, OrigPreheader);
+ MSSAU->updateForClonedBlockIntoPred(OrigHeader, OrigPreheader,
+ ValueMapMSSA);
+ }
- if (MSSAU && VerifyMemorySSA)
- MSSAU->getMemorySSA()->verifyMemorySSA();
+ SmallVector<PHINode *, 2> InsertedPHIs;
+ // If there were any uses of instructions in the duplicated block outside the
+ // loop, update them, inserting PHI nodes as required
+ RewriteUsesOfClonedInstructions(OrigHeader, OrigPreheader, ValueMap, SE,
+ &InsertedPHIs);
+
+ // Attach debug records to the new phis if that phi uses a value that
+ // previously had debug metadata attached. This keeps the debug info
+ // up-to-date in the loop body.
+ if (!InsertedPHIs.empty())
+ insertDebugValuesForPHIs(OrigHeader, InsertedPHIs);
+
+ // NewHeader is now the header of the loop.
+ L->moveToHeader(NewHeader);
+ assert(L->getHeader() == NewHeader && "Latch block is our new header");
+
+ // Inform DT about changes to the CFG.
+ if (DT) {
+ // The OrigPreheader branches to the NewHeader and Exit now. Then, inform
+ // the DT about the removed edge to the OrigHeader (that got removed).
+ SmallVector<DominatorTree::UpdateType, 3> Updates = {
+ {DominatorTree::Insert, OrigPreheader, Exit},
+ {DominatorTree::Insert, OrigPreheader, NewHeader},
+ {DominatorTree::Delete, OrigPreheader, OrigHeader}};
- // Now that the CFG and DomTree are in a consistent state again, try to merge
- // the OrigHeader block into OrigLatch. This will succeed if they are
- // connected by an unconditional branch. This is just a cleanup so the
- // emitted code isn't too gross in this common case.
- DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Eager);
- BasicBlock *PredBB = OrigHeader->getUniquePredecessor();
- bool DidMerge = MergeBlockIntoPredecessor(OrigHeader, &DTU, LI, MSSAU);
- if (DidMerge)
- RemoveRedundantDbgInstrs(PredBB);
+ if (MSSAU) {
+ MSSAU->applyUpdates(Updates, *DT, /*UpdateDT=*/true);
+ if (VerifyMemorySSA)
+ MSSAU->getMemorySSA()->verifyMemorySSA();
+ } else {
+ DT->applyUpdates(Updates);
+ }
+ }
- if (MSSAU && VerifyMemorySSA)
- MSSAU->getMemorySSA()->verifyMemorySSA();
+ // At this point, we've finished our major CFG changes. As part of cloning
+ // the loop into the preheader we've simplified instructions and the
+ // duplicated conditional branch may now be branching on a constant. If it is
+ // branching on a constant and if that constant means that we enter the loop,
+ // then we fold away the cond branch to an uncond branch. This simplifies the
+ // loop in cases important for nested loops, and it also means we don't have
+ // to split as many edges.
+ BranchInst *PHBI = cast<BranchInst>(OrigPreheader->getTerminator());
+ assert(PHBI->isConditional() && "Should be clone of BI condbr!");
+ const Value *Cond = PHBI->getCondition();
+ const bool HasConditionalPreHeader =
+ !isa<ConstantInt>(Cond) ||
+ PHBI->getSuccessor(cast<ConstantInt>(Cond)->isZero()) != NewHeader;
+
+ updateBranchWeights(*PHBI, *BI, HasConditionalPreHeader, BISuccsSwapped);
- LLVM_DEBUG(dbgs() << "LoopRotation: into "; L->dump());
+ if (HasConditionalPreHeader) {
+ // The conditional branch can't be folded, handle the general case.
+ // Split edges as necessary to preserve LoopSimplify form.
+
+ // Right now OrigPreHeader has two successors, NewHeader and ExitBlock, and
+ // thus is not a preheader anymore.
+ // Split the edge to form a real preheader.
+ BasicBlock *NewPH = SplitCriticalEdge(
+ OrigPreheader, NewHeader,
+ CriticalEdgeSplittingOptions(DT, LI, MSSAU).setPreserveLCSSA());
+ NewPH->setName(NewHeader->getName() + ".lr.ph");
+
+ // Preserve canonical loop form, which means that 'Exit' should have only
+ // one predecessor. Note that Exit could be an exit block for multiple
+ // nested loops, causing both of the edges to now be critical and need to
+ // be split.
+ SmallVector<BasicBlock *, 4> ExitPreds(predecessors(Exit));
+ bool SplitLatchEdge = false;
+ for (BasicBlock *ExitPred : ExitPreds) {
+ // We only need to split loop exit edges.
+ Loop *PredLoop = LI->getLoopFor(ExitPred);
+ if (!PredLoop || PredLoop->contains(Exit) ||
+ isa<IndirectBrInst>(ExitPred->getTerminator()))
+ continue;
+ SplitLatchEdge |= L->getLoopLatch() == ExitPred;
+ BasicBlock *ExitSplit = SplitCriticalEdge(
+ ExitPred, Exit,
+ CriticalEdgeSplittingOptions(DT, LI, MSSAU).setPreserveLCSSA());
+ ExitSplit->moveBefore(Exit);
+ }
+ assert(SplitLatchEdge &&
+ "Despite splitting all preds, failed to split latch exit?");
+ (void)SplitLatchEdge;
+ } else {
+ // We can fold the conditional branch in the preheader, this makes things
+ // simpler. The first step is to remove the extra edge to the Exit block.
+ Exit->removePredecessor(OrigPreheader, true /*preserve LCSSA*/);
+ BranchInst *NewBI = BranchInst::Create(NewHeader, PHBI->getIterator());
+ NewBI->setDebugLoc(PHBI->getDebugLoc());
+ PHBI->eraseFromParent();
+
+ // With our CFG finalized, update DomTree if it is available.
+ if (DT)
+ DT->deleteEdge(OrigPreheader, Exit);
+
+ // Update MSSA too, if available.
+ if (MSSAU)
+ MSSAU->removeEdge(OrigPreheader, Exit);
+ }
- ++NumRotated;
+ assert(L->getLoopPreheader() && "Invalid loop preheader after loop rotation");
+ assert(L->getLoopLatch() && "Invalid loop latch after loop rotation");
- Rotated = true;
- SimplifiedLatch = false;
+ if (MSSAU && VerifyMemorySSA)
+ MSSAU->getMemorySSA()->verifyMemorySSA();
+
+ // Now that the CFG and DomTree are in a consistent state again, try to merge
+ // the OrigHeader block into OrigLatch. This will succeed if they are
+ // connected by an unconditional branch. This is just a cleanup so the
+ // emitted code isn't too gross in this common case.
+ DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Eager);
+ BasicBlock *PredBB = OrigHeader->getUniquePredecessor();
+ bool DidMerge = MergeBlockIntoPredecessor(OrigHeader, &DTU, LI, MSSAU);
+ if (DidMerge)
+ RemoveRedundantDbgInstrs(PredBB);
- // Check that new latch is a deoptimizing exit and then repeat rotation if possible.
- // Deoptimizing latch exit is not a generally typical case, so we just loop over.
- // TODO: if it becomes a performance bottleneck extend rotation algorithm
- // to handle multiple rotations in one go.
- } while (MultiRotate && canRotateDeoptimizingLatchExit(L));
+ if (MSSAU && VerifyMemorySSA)
+ MSSAU->getMemorySSA()->verifyMemorySSA();
+ LLVM_DEBUG(dbgs() << "LoopRotation: into "; L->dump());
return true;
}
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index b8cfe3a..155fcc5 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -6642,6 +6642,9 @@ public:
/// Return true if the replacement is a lookup table.
bool isLookupTable();
+ /// Return true if the replacement is a bit map.
+ bool isBitMap();
+
private:
// Depending on the switch, there are different alternatives.
enum {
@@ -6932,6 +6935,8 @@ Constant *SwitchReplacement::getDefaultValue() { return DefaultValue; }
bool SwitchReplacement::isLookupTable() { return Kind == LookupTableKind; }
+bool SwitchReplacement::isBitMap() { return Kind == BitMapKind; }
+
static bool isSwitchDense(uint64_t NumCases, uint64_t CaseRange) {
// 40% is the default density for building a jump table in optsize/minsize
// mode. See also TargetLoweringBase::isSuitableForJumpTable(), which this
@@ -7097,7 +7102,8 @@ static void reuseTableCompare(
/// lookup tables.
static bool simplifySwitchLookup(SwitchInst *SI, IRBuilder<> &Builder,
DomTreeUpdater *DTU, const DataLayout &DL,
- const TargetTransformInfo &TTI) {
+ const TargetTransformInfo &TTI,
+ bool ConvertSwitchToLookupTable) {
assert(SI->getNumCases() > 1 && "Degenerate switch?");
BasicBlock *BB = SI->getParent();
@@ -7262,6 +7268,8 @@ static bool simplifySwitchLookup(SwitchInst *SI, IRBuilder<> &Builder,
bool AnyLookupTables = any_of(
PhiToReplacementMap, [](auto &KV) { return KV.second.isLookupTable(); });
+ bool AnyBitMaps = any_of(PhiToReplacementMap,
+ [](auto &KV) { return KV.second.isBitMap(); });
// A few conditions prevent the generation of lookup tables:
// 1. The target does not support lookup tables.
@@ -7274,6 +7282,12 @@ static bool simplifySwitchLookup(SwitchInst *SI, IRBuilder<> &Builder,
Fn->getFnAttribute("no-jump-tables").getValueAsBool()))
return false;
+ // In the early optimization pipeline, disable formation of lookup tables,
+ // bit maps and mask checks, as they may inhibit further optimization.
+ if (!ConvertSwitchToLookupTable &&
+ (AnyLookupTables || AnyBitMaps || NeedMask))
+ return false;
+
Builder.SetInsertPoint(SI);
// TableIndex is the switch condition - TableIndexOffset if we don't
// use the condition directly
@@ -7929,14 +7943,13 @@ bool SimplifyCFGOpt::simplifySwitch(SwitchInst *SI, IRBuilder<> &Builder) {
if (Options.ForwardSwitchCondToPhi && forwardSwitchConditionToPHI(SI))
return requestResimplify();
- // The conversion from switch to lookup tables results in difficult-to-analyze
- // code and makes pruning branches much harder. This is a problem if the
- // switch expression itself can still be restricted as a result of inlining or
- // CVP. Therefore, only apply this transformation during late stages of the
- // optimisation pipeline.
- if (Options.ConvertSwitchToLookupTable &&
- simplifySwitchLookup(SI, Builder, DTU, DL, TTI))
- return requestResimplify();
+ // The conversion of switches to arithmetic or lookup table is disabled in
+ // the early optimization pipeline, as it may lose information or make the
+ // resulting code harder to analyze.
+ if (Options.ConvertSwitchToArithmetic || Options.ConvertSwitchToLookupTable)
+ if (simplifySwitchLookup(SI, Builder, DTU, DL, TTI,
+ Options.ConvertSwitchToLookupTable))
+ return requestResimplify();
if (simplifySwitchOfPowersOfTwo(SI, Builder, DL, TTI))
return requestResimplify();
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index cee08ef..3f16b03 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -4264,8 +4264,8 @@ bool LoopVectorizationPlanner::isCandidateForEpilogueVectorization(
if (any_of(OrigLoop->getHeader()->phis(), [&](PHINode &Phi) {
if (!Legal->isReductionVariable(&Phi))
return Legal->isFixedOrderRecurrence(&Phi);
- RecurKind RK = Legal->getRecurrenceDescriptor(&Phi).getRecurrenceKind();
- return RK == RecurKind::FMinNum || RK == RecurKind::FMaxNum;
+ return RecurrenceDescriptor::isFPMinMaxNumRecurrenceKind(
+ Legal->getRecurrenceDescriptor(&Phi).getRecurrenceKind());
}))
return false;
@@ -7282,8 +7282,8 @@ DenseMap<const SCEV *, Value *> LoopVectorizationPlanner::executePlan(
if (!Exit->hasPredecessors())
continue;
for (VPRecipeBase &PhiR : Exit->phis())
- SE.forgetLcssaPhiWithNewPredecessor(
- OrigLoop, cast<PHINode>(&cast<VPIRPhi>(PhiR).getInstruction()));
+ SE.forgetLcssaPhiWithNewPredecessor(OrigLoop,
+ &cast<VPIRPhi>(PhiR).getIRPhi());
}
// Forget the original loop and block dispositions.
SE.forgetLoop(OrigLoop);
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 91c3d42..cfa8d27 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -10621,7 +10621,8 @@ class InstructionsCompatibilityAnalysis {
/// elements.
static bool isSupportedOpcode(const unsigned Opcode) {
return Opcode == Instruction::Add || Opcode == Instruction::LShr ||
- Opcode == Instruction::Shl;
+ Opcode == Instruction::Shl || Opcode == Instruction::SDiv ||
+ Opcode == Instruction::UDiv;
}
/// Identifies the best candidate value, which represents main opcode
@@ -10939,6 +10940,8 @@ public:
case Instruction::Add:
case Instruction::LShr:
case Instruction::Shl:
+ case Instruction::SDiv:
+ case Instruction::UDiv:
VectorCost = TTI.getArithmeticInstrCost(MainOpcode, VecTy, Kind);
break;
default:
@@ -22066,8 +22069,10 @@ bool BoUpSLP::collectValuesToDemote(
auto Checker = [&](unsigned BitWidth, unsigned OrigBitWidth) {
assert(BitWidth <= OrigBitWidth && "Unexpected bitwidths!");
return all_of(E.Scalars, [&](Value *V) {
- auto *I = cast<Instruction>(V);
APInt Mask = APInt::getBitsSetFrom(OrigBitWidth, BitWidth);
+ if (E.hasCopyableElements() && E.isCopyableElement(V))
+ return MaskedValueIsZero(V, Mask, SimplifyQuery(*DL));
+ auto *I = cast<Instruction>(V);
return MaskedValueIsZero(I->getOperand(0), Mask, SimplifyQuery(*DL)) &&
MaskedValueIsZero(I->getOperand(1), Mask, SimplifyQuery(*DL));
});
diff --git a/llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp b/llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp
index c8212af..81deba2 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp
@@ -763,6 +763,8 @@ void VPlanTransforms::addMinimumVectorEpilogueIterationCheck(
// Add the minimum iteration check for the epilogue vector loop.
VPValue *TC = Plan.getOrAddLiveIn(TripCount);
VPBuilder Builder(cast<VPBasicBlock>(Plan.getEntry()));
+ VPValue *VFxUF = Builder.createExpandSCEV(SE.getElementCount(
+ TripCount->getType(), (EpilogueVF * EpilogueUF), SCEV::FlagNUW));
VPValue *Count = Builder.createNaryOp(
Instruction::Sub, {TC, Plan.getOrAddLiveIn(VectorTripCount)},
DebugLoc::getUnknown(), "n.vec.remaining");
@@ -770,9 +772,6 @@ void VPlanTransforms::addMinimumVectorEpilogueIterationCheck(
// Generate code to check if the loop's trip count is less than VF * UF of
// the vector epilogue loop.
auto P = RequiresScalarEpilogue ? ICmpInst::ICMP_ULE : ICmpInst::ICMP_ULT;
- VPValue *VFxUF = Builder.createExpandSCEV(SE.getElementCount(
- TripCount->getType(), (EpilogueVF * EpilogueUF), SCEV::FlagNUW));
-
auto *CheckMinIters = Builder.createICmp(
P, Count, VFxUF, DebugLoc::getUnknown(), "min.epilog.iters.check");
VPInstruction *Branch =
@@ -841,8 +840,8 @@ bool VPlanTransforms::handleMaxMinNumReductions(VPlan &Plan) {
// TODO: Support multiple MaxNum/MinNum reductions and other reductions.
if (RedPhiR)
return false;
- if (Cur->getRecurrenceKind() != RecurKind::FMaxNum &&
- Cur->getRecurrenceKind() != RecurKind::FMinNum) {
+ if (!RecurrenceDescriptor::isFPMinMaxNumRecurrenceKind(
+ Cur->getRecurrenceKind())) {
HasUnsupportedPhi = true;
continue;
}
@@ -862,10 +861,9 @@ bool VPlanTransforms::handleMaxMinNumReductions(VPlan &Plan) {
if (!MinMaxOp)
return false;
- RecurKind RedPhiRK = RedPhiR->getRecurrenceKind();
- assert((RedPhiRK == RecurKind::FMaxNum || RedPhiRK == RecurKind::FMinNum) &&
+ assert(RecurrenceDescriptor::isFPMinMaxNumRecurrenceKind(
+ RedPhiR->getRecurrenceKind()) &&
"unsupported reduction");
- (void)RedPhiRK;
/// Check if the vector loop of \p Plan can early exit and restart
/// execution of last vector iteration in the scalar loop. This requires all
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index 94e2628..3a9770c 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -1230,6 +1230,7 @@ bool VPInstruction::opcodeMayReadOrWriteFromMemory() const {
case VPInstruction::ExtractLane:
case VPInstruction::ExtractLastElement:
case VPInstruction::ExtractPenultimateElement:
+ case VPInstruction::ActiveLaneMask:
case VPInstruction::FirstActiveLane:
case VPInstruction::FirstOrderRecurrenceSplice:
case VPInstruction::LogicalAnd:
generated by cgit v1.1 at 2025-10-08 18:48:10 +0000