mlir::dataflow::IntegerValueRangeLattice Class Reference

This lattice element represents the integer value range of an SSA value. More...

#include "mlir/Analysis/DataFlow/IntegerRangeAnalysis.h"

Inheritance diagram for mlir::dataflow::IntegerValueRangeLattice:

Public Member Functions
ChangeResult	join (const AbstractSparseLattice &rhs) override
	Join the information contained in 'rhs' into this lattice.
ChangeResult	join (const ValueT &rhs)
	Join the information contained in the 'rhs' value into this lattice.
Public Member Functions inherited from mlir::dataflow::Lattice< IntegerValueRange >
	AbstractSparseLattice (Value value)
	Lattices can only be created for values.
Value	getAnchor () const
	Return the value this lattice is located at.
IntegerValueRange &	getValue ()
	Return the value held by this lattice.
ChangeResult	join (const AbstractSparseLattice &rhs) override
	Join the information contained in the 'rhs' lattice into this lattice.
ChangeResult	meet (const AbstractSparseLattice &rhs) override
	Meet (intersect) the information contained in the 'rhs' lattice with this lattice.
void	print (raw_ostream &os) const override
	Print the lattice element.
Public Member Functions inherited from mlir::dataflow::AbstractSparseLattice
	AbstractSparseLattice (Value value)
	Lattices can only be created for values.
Value	getAnchor () const
	Return the value this lattice is located at.
void	onUpdate (DataFlowSolver *solver) const override
	When the lattice gets updated, propagate an update to users of the value using its use-def chain to subscribed analyses.
void	useDefSubscribe (DataFlowAnalysis *analysis)
	Subscribe an analysis to updates of the lattice.
Public Member Functions inherited from mlir::AnalysisState
virtual	~AnalysisState ()
	AnalysisState (LatticeAnchor anchor)
	Create the analysis state on the given lattice anchor.
LatticeAnchor	getAnchor () const
	Returns the lattice anchor this state is located at.
LLVM_DUMP_METHOD void	dump () const
void	addDependency (ProgramPoint *point, DataFlowAnalysis *analysis)
	Add a dependency to this analysis state on a lattice anchor and an analysis.

Additional Inherited Members
Public Types inherited from mlir::dataflow::Lattice< IntegerValueRange >
using	LatticeT
using	has_meet
	Trait to check if T provides a meet method.
using	lattice_has_meet
Protected Attributes inherited from mlir::AnalysisState
LatticeAnchor	anchor
	The lattice anchor to which the state belongs.

Detailed Description

This lattice element represents the integer value range of an SSA value.

join overrides the base behaviour to apply per-state widening: once the lattice has absorbed enough strictly-increasing merges the range is forced to its max as a sound over-approximation. This is the sole convergence guarantee for IntegerRangeAnalysis on loop-carried values; without it, scf.while loops with dynamic bounds and nested region ops can keep the solver ratcheting a loop-carried range by +1 per worklist visit for up to 2^31 iterations on i32. The budget is sized to be much larger than realistic merge counts on naturally bounded accumulators (e.g. arith.minsi/arith.andi-clamped iter args) so the analysis still converges to a tight range on those.

Note that only the (const AbstractSparseLattice &) overload is overridden, so the widening fires only at framework merge sites (block-arg / region-successor / callable-arg joins) — transfer-function updates that go through the non-virtual join(const ValueT &) overload are unaffected.

Definition at line 46 of file IntegerRangeAnalysis.h.

Member Function Documentation

join() [1/2]

ChangeResult IntegerValueRangeLattice::join ( const AbstractSparseLattice & rhs )

overridevirtual

Join the information contained in 'rhs' into this lattice.

Returns if the value of the lattice changed.

Reimplemented from mlir::dataflow::AbstractSparseLattice.

Definition at line 73 of file IntegerRangeAnalysis.cpp.

References mlir::dataflow::Lattice< IntegerValueRange >::AbstractSparseLattice(), mlir::Change, mlir::dataflow::Lattice< IntegerValueRange >::getAnchor(), mlir::IntegerValueRange::getMaxRange(), mlir::dataflow::Lattice< ValueT >::join(), kIntegerRangeWideningBudget, and rhs.

Referenced by copyIntegerRange(), mlir::dataflow::IntegerRangeAnalysis::setToEntryState(), mlir::dataflow::IntegerRangeAnalysis::visitNonControlFlowArguments(), and mlir::dataflow::IntegerRangeAnalysis::visitOperation().

join() [2/2]

ChangeResult mlir::dataflow::Lattice< ValueT >::join ( const ValueT & rhs )

inline

Join the information contained in the 'rhs' value into this lattice.

Returns if the state of the current lattice changed.

Definition at line 115 of file SparseAnalysis.h.

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

• include/mlir/Analysis/DataFlow/IntegerRangeAnalysis.h
• lib/Analysis/DataFlow/IntegerRangeAnalysis.cpp