LLVM: llvm::SCEV Class Reference (original) (raw)

This class represents an analyzed expression in the program. More...

#include "[llvm/Analysis/ScalarEvolution.h](ScalarEvolution%5F8h%5Fsource.html)"

This class represents an analyzed expression in the program.

These are opaque objects that the client is not allowed to do much with directly.

Definition at line 72 of file ScalarEvolution.h.

◆ NoWrapFlags

NoWrapFlags are bitfield indices into SubclassData.

Add and Mul expressions may have no-unsigned-wrap or no-signed-wrap properties, which are derived from the IR operator. NSW is a misnomer that we use to mean no signed overflow or underflow.

AddRec expressions may have a no-self-wraparound property if, in the integer domain, abs(step) * max-iteration(loop) <= unsigned-max(bitwidth). This means that the recurrence will never reach its start value if the step is non-zero. Computing the same value on each iteration is not considered wrapping, and recurrences with step = 0 are trivially . is independent of the sign of step and the value the add recurrence starts with.

Note that NUW and NSW are also valid properties of a recurrence, and either implies NW. For convenience, NW will be set for a recurrence whenever either NUW or NSW are set.

We require that the flag on a SCEV apply to the entire scope in which that SCEV is defined. A SCEV's scope is set of locations dominated by a defining location, which is in turn described by the following rules:

• A SCEVUnknown is at the point of definition of the Value.
• A SCEVConstant is defined at all points.
• A SCEVAddRec is defined starting with the header of the associated loop.
• All other SCEVs are defined at the earlest point all operands are defined.

The above rules describe a maximally hoisted form (without regards to potential control dependence). A SCEV is defined anywhere a corresponding instruction could be defined in said maximally hoisted form. Note that SCEVUDivExpr (currently the only expression type which can trap) can be defined per these rules in regions where it would trap at runtime. A SCEV being defined does not require the existence of any instruction within the defined scope.

Definition at line 127 of file ScalarEvolution.h.

◆ SCEV() [1/2]

Definition at line 135 of file ScalarEvolution.h.

References ExpressionSize.

Referenced by llvm::SCEVCastExpr::classof(), llvm::SCEVConstant::classof(), llvm::SCEVCouldNotCompute::classof(), llvm::SCEVNAryExpr::classof(), llvm::SCEVUDivExpr::classof(), llvm::SCEVUnknown::classof(), llvm::SCEVVScale::classof(), llvm::SCEVUDivExpr::getLHS(), llvm::SCEVCastExpr::getOperand(), llvm::SCEVCastExpr::getOperand(), llvm::SCEVNAryExpr::getOperand(), llvm::SCEVUDivExpr::getOperand(), llvm::SCEVUDivExpr::getRHS(), operator=(), print(), llvm::SCEVConstant::ScalarEvolution, llvm::SCEVUDivExpr::ScalarEvolution, llvm::SCEVUnknown::ScalarEvolution, llvm::SCEVVScale::ScalarEvolution, SCEV(), llvm::SCEVCastExpr::SCEVCastExpr(), llvm::SCEVCouldNotCompute::SCEVCouldNotCompute(), and llvm::SCEVNAryExpr::SCEVNAryExpr().

◆ SCEV() [2/2]

◆ dump()

◆ getExpressionSize()

◆ getSCEVType()

Definition at line 141 of file ScalarEvolution.h.

Referenced by llvm::SCEVAddExpr::classof(), llvm::SCEVAddRecExpr::classof(), llvm::SCEVCastExpr::classof(), llvm::SCEVCommutativeExpr::classof(), llvm::SCEVConstant::classof(), llvm::SCEVCouldNotCompute::classof(), llvm::SCEVIntegralCastExpr::classof(), llvm::SCEVMinMaxExpr::classof(), llvm::SCEVMulExpr::classof(), llvm::SCEVNAryExpr::classof(), llvm::SCEVPtrToIntExpr::classof(), llvm::SCEVSequentialMinMaxExpr::classof(), llvm::SCEVSequentialUMinExpr::classof(), llvm::SCEVSignExtendExpr::classof(), llvm::SCEVSMaxExpr::classof(), llvm::SCEVSMinExpr::classof(), llvm::SCEVTruncateExpr::classof(), llvm::SCEVUDivExpr::classof(), llvm::SCEVUMaxExpr::classof(), llvm::SCEVUMinExpr::classof(), llvm::SCEVUnknown::classof(), llvm::SCEVVScale::classof(), llvm::SCEVZeroExtendExpr::classof(), llvm::SCEVSequentialMinMaxExpr::getEquivalentNonSequentialSCEVType(), getExprBase(), getType(), GroupByComplexity(), isHighCostExpansion(), operands(), print(), SCEVMinMaxExprContains(), llvm::SCEVVisitor< SCEVSequentialMinMaxDeduplicatingVisitor, RetVal >::visit(), and llvm::SCEVTraversal< SV >::visitAll().

◆ getType()

Return the LLVM type of this SCEV expression.

Definition at line 383 of file ScalarEvolution.cpp.

References llvm::cast(), getSCEVType(), llvm_unreachable, llvm::scAddExpr, llvm::scAddRecExpr, llvm::scConstant, llvm::scCouldNotCompute, llvm::scMulExpr, llvm::scPtrToInt, llvm::scSequentialUMinExpr, llvm::scSignExtend, llvm::scSMaxExpr, llvm::scSMinExpr, llvm::scTruncate, llvm::scUDivExpr, llvm::scUMaxExpr, llvm::scUMinExpr, llvm::scUnknown, llvm::scVScale, and llvm::scZeroExtend.

Referenced by llvm::VPlanTransforms::addMinimumIterationCheck(), llvm::SCEVAAResult::alias(), BinomialCoefficient(), calculateRtStride(), llvm::cannotBeMaxInLoop(), llvm::cannotBeMinInLoop(), CollectSubexprs(), llvm::ScalarEvolution::computeConstantDifference(), llvm::LoopVectorizationCostModel::computeMaxVF(), llvm::IndexedReference::computeRefCost(), computeTripCount(), llvm::ScalarEvolution::convertSCEVToAddRecWithPredicates(), countToEliminateCompares(), createNodeForSelectViaUMinSeq(), createReplacement(), llvm::delinearizeFixedSizeArray(), llvm::DependenceInfo::depends(), DoInitialMatch(), evaluatePtrAddRecAtMaxBTCWillNotWrap(), expandBounds(), llvm::SCEVExpander::expandCodeFor(), llvm::VPlanTransforms::expandSCEVs(), ExtractImmediate(), FindLoopCounter(), findSplitCandidate(), llvm::SCEVExpander::generateOverflowCheck(), genLoopLimit(), llvm::ScalarEvolution::getAnyExtendExpr(), llvm::ScalarEvolution::getGEPExpr(), llvm::ScalarEvolution::getLoopInvariantExitCondDuringFirstIterationsImpl(), llvm::ScalarEvolution::getLosslessPtrToIntExpr(), llvm::ScalarEvolution::getMinTrailingZeros(), getNewAlignment(), llvm::vputils::getSCEVExprForVPValue(), getSignedOverflowLimitForStep(), llvm::ScalarEvolution::getSignExtendExprImpl(), getSmallConstantTripCount(), llvm::getStartAndEndForAccess(), llvm::ScalarEvolution::getTripCountFromExitCount(), llvm::ScalarEvolution::getTripCountFromExitCount(), llvm::SCEVAddRecExpr::getType(), llvm::SCEVMinMaxExpr::getType(), llvm::SCEVMulExpr::getType(), llvm::SCEVSequentialMinMaxExpr::getType(), llvm::SCEVUDivExpr::getType(), llvm::ScalarEvolution::getUMinFromMismatchedTypes(), getUnsignedOverflowLimitForStep(), llvm::ScalarEvolution::getZeroExtendExprImpl(), llvm::hasIterationCountInvariantInParent(), llvm::SCEVWrapPredicate::implies(), isConditionTrueViaVFAndUF(), llvm::ARMTTIImpl::isHardwareLoopProfitable(), isKnownLessThan(), llvm::ScalarEvolution::isKnownMultipleOf(), llvm::isKnownNegativeInLoop(), llvm::isKnownNonNegativeInLoop(), llvm::isKnownNonPositiveInLoop(), llvm::isKnownPositiveInLoop(), llvm::ScalarEvolution::isLoopBackedgeGuardedByCond(), isSafeDecreasingBound(), isSafeDependenceDistance(), isSafeIncreasingBound(), IsSimplerBaseSCEVForTarget(), llvm::SCEVPatternMatch::bind_cst_ty::match(), llvm::SCEVPatternMatch::cst_pred_ty< Predicate >::match(), llvm::SCEVPatternMatch::SCEVURem_match< Op0_t, Op1_t >::match(), mayUsePostIncMode(), optimizeLoopExitWithUnknownExitCount(), llvm::LoopStructure::parseLoopStructure(), llvm::peelLoop(), PrintSCEVWithTypeHint(), llvm::replaceSymbolicStrideSCEV(), llvm::ScalarEvolution::LoopGuards::rewrite(), shouldPeelLastIteration(), simplifyBranchConditionForVFAndUF(), simplifyKnownEVL(), splitLoopBound(), llvm::UnrollRuntimeLoopRemainder(), llvm::validateDelinearizationResult(), verifyTripCount(), llvm::SCEVDivision::visitAddExpr(), llvm::SCEVDivision::visitAddRecExpr(), and llvm::SCEVDivision::visitMulExpr().

◆ isAllOnesValue()

◆ isNonConstantNegative()

◆ isOne()

◆ isZero()

Return true if the expression is a constant zero.

Definition at line 445 of file ScalarEvolution.cpp.

References llvm::SCEVPatternMatch::m_scev_Zero(), and llvm::PatternMatch::match().

Referenced by breakBackedgeIfNotTaken(), calculateRtStride(), llvm::LoopVectorizationCostModel::computeMaxVF(), llvm::DependenceInfo::depends(), llvm::SCEVDivision::divide(), dumpExampleDependence(), evaluatePtrAddRecAtMaxBTCWillNotWrap(), llvm::findArrayDimensions(), FindLoopCounter(), isAlwaysFoldable(), llvm::LoopVectorizationPlanner::selectEpilogueVectorizationFactor(), SolveQuadraticAddRecRange(), and llvm::ScalarEvolution::verify().

◆ operands()

Return operands of this SCEV expression.

Definition at line 417 of file ScalarEvolution.cpp.

References llvm::cast(), getSCEVType(), llvm_unreachable, llvm::scAddExpr, llvm::scAddRecExpr, llvm::scConstant, llvm::scCouldNotCompute, llvm::scMulExpr, llvm::scPtrToInt, llvm::scSequentialUMinExpr, llvm::scSignExtend, llvm::scSMaxExpr, llvm::scSMinExpr, llvm::scTruncate, llvm::scUDivExpr, llvm::scUMaxExpr, llvm::scUMinExpr, llvm::scUnknown, llvm::scVScale, and llvm::scZeroExtend.

Referenced by llvm::ScalarEvolution::computeConstantDifference(), llvm::ScalarEvolution::getMulExpr(), llvm::ScalarEvolution::getNotSCEV(), getSetupCost(), llvm::ScalarEvolution::verify(), and llvm::SCEVTraversal< SV >::visitAll().

◆ operator=()

◆ print()

Print out the internal representation of this scalar to the specified stream.

This should really only be used for debugging purposes.

Definition at line 272 of file ScalarEvolution.cpp.

References llvm::cast(), FlagNSW, FlagNUW, llvm::LoopBase< BlockT, LoopT >::getHeader(), llvm::SCEVUDivExpr::getLHS(), llvm::SCEVAddRecExpr::getLoop(), llvm::SCEVNAryExpr::getNoWrapFlags(), llvm::SCEVNAryExpr::getNumOperands(), llvm::SCEVCastExpr::getOperand(), llvm::SCEVNAryExpr::getOperand(), llvm::SCEVUDivExpr::getRHS(), getSCEVType(), llvm::SCEVCastExpr::getType(), llvm::SCEVNAryExpr::hasNoSelfWrap(), llvm::SCEVNAryExpr::hasNoSignedWrap(), llvm::SCEVNAryExpr::hasNoUnsignedWrap(), llvm::interleaved(), llvm_unreachable, llvm::make_pointee_range(), llvm::SCEVNAryExpr::operands(), llvm::Value::printAsOperand(), llvm::scAddExpr, llvm::scAddRecExpr, llvm::scConstant, llvm::scCouldNotCompute, SCEV(), llvm::scMulExpr, llvm::scPtrToInt, llvm::scSequentialUMinExpr, llvm::scSignExtend, llvm::scSMaxExpr, llvm::scSMinExpr, llvm::scTruncate, llvm::scUDivExpr, llvm::scUMaxExpr, llvm::scUMinExpr, llvm::scUnknown, llvm::scVScale, and llvm::scZeroExtend.

Referenced by dump(), llvm::operator<<(), and llvm::ScalarEvolution::print().

◆ FoldingSetTrait< SCEV >

◆ ExpressionSize

◆ SubclassData

The documentation for this class was generated from the following files:

• include/llvm/Analysis/ScalarEvolution.h
• lib/Analysis/ScalarEvolution.cpp