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+/* Functions to support fixed-length bitmaps.
+ Copyright (C) 2024 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#ifndef GCC_BBITMAP_H
+#define GCC_BBITMAP_H
+
+/* Implementation of bounded (fixed length) bitmaps.
+
+ This provides a drop-in replacement for bitmaps that have outgrown the
+ storage capacity of a single integer.
+
+ Sets are stored as a fixed length array of uint64_t elements. The length of
+ this array is given as a template parameter. */
+
+/* Use recusive templated functions to define constexpr operations. */
+template<int M>
+struct bbitmap_operators
+{
+ /* Return a result that maps binary operator OP to elements [0, M) of
+ X and Y, and takes the remaining elements from REST. */
+ template<typename Result, typename Operator, typename Arg, typename ...Rest>
+ static constexpr Result binary(Operator op, const Arg &x, const Arg &y,
+ Rest ...rest)
+ {
+ return bbitmap_operators<M - 1>::template binary<Result, Operator, Arg>
+ (op, x, y, op (x.val[M - 1], y.val[M - 1]), rest...);
+ }
+
+ /* Return a result that contains the bitwise inverse of elements [0, M) of X,
+ and takes the remaining elements from REST. */
+ template<typename Result, typename Arg, typename ...Rest>
+ static constexpr Result bit_not(const Arg &x, Rest ...rest)
+ {
+ return bbitmap_operators<M - 1>::template bit_not<Result, Arg>
+ (x, ~(x.val[M - 1]), rest...);
+ }
+
+ /* Return true if any element [0, M) of X is nonzero. */
+ template<typename Arg>
+ static constexpr bool non_zero(const Arg &x)
+ {
+ return (bool) x.val[M - 1]
+ || bbitmap_operators<M - 1>::template non_zero<Arg> (x);
+ }
+
+ /* Return true if elements [0, M) of X are all equal to the corresponding
+ elements of Y. */
+ template<typename Arg>
+ static constexpr bool equal(const Arg &x, const Arg &y)
+ {
+ return x.val[M - 1] == y.val[M - 1]
+ && bbitmap_operators<M - 1>::template equal<Arg> (x, y);
+ }
+
+ /* If bit index INDEX selects a bit in the first M elements, return a
+ Result with that bit set and the other bits of the leading M elements
+ clear. Clear the leading M elements otherwise. Take the remaining
+ elements of the Result from REST. */
+ template<typename Result, typename ...Rest>
+ static constexpr Result from_index(int index, Rest ...rest)
+ {
+ return bbitmap_operators<M - 1>::template from_index<Result>
+ (index,
+ uint64_t ((index - (M - 1) * 64) == (index & 63)) << (index & 63),
+ rest...);
+ }
+};
+
+/* These functions form the base for the recursive functions above. They
+ return either bitmap containing the elements passed in REST, or a default
+ bool result. */
+template<>
+struct bbitmap_operators<0>
+{
+ template<typename Result, typename Operator, typename Arg, typename ...Rest>
+ static constexpr Result binary(Operator, const Arg, const Arg,
+ Rest ...rest)
+ {
+ return Result { rest... };
+ }
+
+ template<typename Result, typename Arg, typename ...Rest>
+ static constexpr Result bit_not(const Arg, Rest ...rest)
+ {
+ return Result { rest... };
+ }
+
+ template<typename Arg>
+ static constexpr bool non_zero(const Arg)
+ {
+ return false;
+ }
+
+ template<typename Arg>
+ static constexpr bool equal(const Arg, const Arg)
+ {
+ return true;
+ }
+
+ template<typename Result, typename ...Rest>
+ static constexpr Result from_index(int, Rest ...rest)
+ {
+ return Result { rest... };
+ }
+};
+
+template<typename T>
+constexpr T bbitmap_element_or(T x, T y) { return x | y;}
+
+template<typename T>
+constexpr T bbitmap_element_and(T x, T y) { return x & y;}
+
+template<typename T>
+constexpr T bbitmap_element_xor(T x, T y) { return x ^ y;}
+
+
+
+template <int N>
+class GTY((user)) bbitmap
+{
+public:
+ uint64_t val[N];
+
+ template<typename... Rest>
+ constexpr bbitmap(Rest ...rest) : val{(uint64_t) rest...} {}
+
+ constexpr bbitmap<N> operator|(const bbitmap<N> other) const
+ {
+ return bbitmap_operators<N>::template binary<bbitmap<N>>
+ (bbitmap_element_or<uint64_t>, *this, other);
+ }
+
+ bbitmap<N> operator|=(const bbitmap<N> other)
+ {
+ for (int i = 0; i < N; i++)
+ val[i] |= other.val[i];
+
+ return this;
+ }
+
+ constexpr bbitmap<N> operator&(const bbitmap<N> other) const
+ {
+ return bbitmap_operators<N>::template binary<bbitmap<N>>
+ (bbitmap_element_and<uint64_t>, *this, other);
+ }
+
+ bbitmap<N> operator&=(const bbitmap<N> other)
+ {
+ for (int i = 0; i < N; i++)
+ val[i] &= other.val[i];
+
+ return this;
+ }
+
+ constexpr bbitmap<N> operator^(const bbitmap<N> other) const
+ {
+ return bbitmap_operators<N>::template binary<bbitmap<N>>
+ (bbitmap_element_xor<uint64_t>, *this, other);
+ }
+
+ bbitmap<N> operator^=(const bbitmap<N> other)
+ {
+ for (int i = 0; i < N; i++)
+ val[i] ^= other.val[i];
+
+ return this;
+ }
+
+ constexpr bbitmap<N> operator~() const
+ {
+ return bbitmap_operators<N>::template bit_not<bbitmap<N>>(*this);
+ }
+
+ constexpr bool operator!() const
+ {
+ return !(bbitmap_operators<N>::template non_zero<bbitmap<N>>(*this));
+ }
+
+ constexpr explicit operator bool() const
+ {
+ return bbitmap_operators<N>::template non_zero<bbitmap<N>>(*this);
+ }
+
+ constexpr bool operator==(const bbitmap<N> other) const
+ {
+ return bbitmap_operators<N>::template equal<bbitmap<N>>(*this, other);
+ }
+
+ constexpr bool operator!=(const bbitmap<N> other) const
+ {
+ return !(bbitmap_operators<N>::template equal<bbitmap<N>>(*this, other));
+ }
+
+ /* Return a bitmap with bit INDEX set and all other bits clear. */
+
+ static constexpr bbitmap<N> from_index (int index)
+ {
+ return bbitmap_operators<N>::template from_index<bbitmap<N>> (index);
+ }
+};
+
+template<int N>
+void
+gt_ggc_mx (bbitmap<N> *)
+{
+}
+
+template<int N>
+void
+gt_pch_nx (bbitmap<N> *)
+{
+}
+
+template<int N>
+void
+gt_pch_nx (bbitmap<N> *, gt_pointer_operator, void *)
+{
+}
+
+#endif