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//===- IntegerSet.h - MLIR Integer Set Class --------------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// Integer sets are sets of points from the integer lattice constrained by
// affine equality/inequality constraints. This class is meant to represent
// integer sets in the IR - for 'affine.if' operations and as attributes of
// other operations. It is typically expected to contain only a handful of
// affine constraints, and is immutable like an affine map. Integer sets are not
// unique'd unless the number of constraints they contain are below a certain
// threshold - although affine expressions that make up its equalities and
// inequalities are themselves unique.
// This class is not meant for affine analysis and operations like set
// operations, emptiness checks, or other math operations for analysis and
// transformation. For the latter, use FlatAffineConstraints.
#include "mlir/IR/AffineExpr.h"
#include "llvm/ADT/ArrayRef.h"
namespace mlir {
namespace detail {
struct IntegerSetStorage;
} // end namespace detail
class MLIRContext;
/// An integer set representing a conjunction of one or more affine equalities
/// and inequalities. An integer set in the IR is immutable like the affine map,
/// but integer sets are not unique'd unless the number of constraints in them
/// is below `kUniquingThreshold`. The affine expressions that make up the
/// equalities and inequalities of an integer set are themselves unique and are
/// allocated by the bump pointer allocator.
class IntegerSet {
using ImplType = detail::IntegerSetStorage;
constexpr IntegerSet() : set(nullptr) {}
explicit IntegerSet(ImplType *set) : set(set) {}
static IntegerSet get(unsigned dimCount, unsigned symbolCount,
ArrayRef<AffineExpr> constraints,
ArrayRef<bool> eqFlags);
// Returns the canonical empty IntegerSet (i.e. a set with no integer points).
static IntegerSet getEmptySet(unsigned numDims, unsigned numSymbols,
MLIRContext *context) {
auto one = getAffineConstantExpr(1, context);
// 1 == 0.
return get(numDims, numSymbols, one, true);
/// Returns true if this is the canonical integer set.
bool isEmptyIntegerSet() const;
/// This method substitutes any uses of dimensions and symbols (e.g.
/// dim#0 with dimReplacements[0]) in subexpressions and returns the modified
/// integer set. Because this can be used to eliminate dims and
/// symbols, the client needs to specify the number of dims and symbols in
/// the result. The returned map always has the same number of results.
IntegerSet replaceDimsAndSymbols(ArrayRef<AffineExpr> dimReplacements,
ArrayRef<AffineExpr> symReplacements,
unsigned numResultDims,
unsigned numResultSyms);
explicit operator bool() { return set; }
bool operator==(IntegerSet other) const { return set == other.set; }
unsigned getNumDims() const;
unsigned getNumSymbols() const;
unsigned getNumInputs() const;
unsigned getNumConstraints() const;
unsigned getNumEqualities() const;
unsigned getNumInequalities() const;
ArrayRef<AffineExpr> getConstraints() const;
AffineExpr getConstraint(unsigned idx) const;
/// Returns the equality bits, which specify whether each of the constraints
/// is an equality or inequality.
ArrayRef<bool> getEqFlags() const;
/// Returns true if the idx^th constraint is an equality, false if it is an
/// inequality.
bool isEq(unsigned idx) const;
MLIRContext *getContext() const;
/// Walk all of the AffineExpr's in this set's constraints. Each node in an
/// expression tree is visited in postorder.
void walkExprs(function_ref<void(AffineExpr)> callback) const;
void print(raw_ostream &os) const;
void dump() const;
friend ::llvm::hash_code hash_value(IntegerSet arg);
/// Methods supporting C API.
const void *getAsOpaquePointer() const {
return static_cast<const void *>(set);
static IntegerSet getFromOpaquePointer(const void *pointer) {
return IntegerSet(
reinterpret_cast<ImplType *>(const_cast<void *>(pointer)));
ImplType *set;
/// Sets with constraints fewer than kUniquingThreshold are uniqued.
constexpr static unsigned kUniquingThreshold = 4;
// Make AffineExpr hashable.
inline ::llvm::hash_code hash_value(IntegerSet arg) {
return ::llvm::hash_value(arg.set);
} // end namespace mlir
namespace llvm {
// IntegerSet hash just like pointers.
template <> struct DenseMapInfo<mlir::IntegerSet> {
static mlir::IntegerSet getEmptyKey() {
auto *pointer = llvm::DenseMapInfo<void *>::getEmptyKey();
return mlir::IntegerSet(static_cast<mlir::IntegerSet::ImplType *>(pointer));
static mlir::IntegerSet getTombstoneKey() {
auto *pointer = llvm::DenseMapInfo<void *>::getTombstoneKey();
return mlir::IntegerSet(static_cast<mlir::IntegerSet::ImplType *>(pointer));
static unsigned getHashValue(mlir::IntegerSet val) {
return mlir::hash_value(val);
static bool isEqual(mlir::IntegerSet LHS, mlir::IntegerSet RHS) {
return LHS == RHS;
} // namespace llvm