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//===--- APIntMap.h - A map with APInts as the keys -------------*- C++ -*-===//
// This source file is part of the open source project
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
// See for license information
// See for the list of Swift project authors
// LLVM does not allow arbitrary APInts to be the keys of a DenseMap because
// APInts are only comparable if they have the same bit-width. This map
// implementation assumes that its keys will always be constrained to their
// minimum width, so it's not a general-purpose structure, but it does work.
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/DenseMap.h"
#include "swift/Basic/LLVM.h"
namespace swift {
struct WidthPreservingAPIntDenseMapInfo {
// For the special values, we use -1 with a bit-width that isn't minimal
// for the value, then use a parser that always produces values with
// minimal bit-widths so that we don't get a conflict.
static inline APInt getEmptyKey() {
return APInt::getAllOnesValue(/*bitwidth*/2);
static inline APInt getTombstoneKey() {
return APInt::getAllOnesValue(/*bitwidth*/3);
static unsigned getHashValue(const APInt &Key) {
return static_cast<unsigned>(hash_value(Key));
static bool isEqual(const APInt &LHS, const APInt &RHS) {
return LHS.getBitWidth() == RHS.getBitWidth() && LHS == RHS;
template <class Value>
using APIntMap = llvm::DenseMap<APInt, Value, WidthPreservingAPIntDenseMapInfo>;