P2876R3 Proposal to extend std::simd with more constructors and accessors

Author: mattkretz

source/numerics.tex

@@ -19096,6 +19096,8 @@
     template<size_t UBytes, class UAbi>
       constexpr explicit basic_simd_mask(const basic_simd_mask<UBytes, UAbi>&) noexcept;
     template<class G> constexpr explicit basic_simd_mask(G&& gen) noexcept;
+    constexpr basic_simd_mask(const bitset<size()>& b) noexcept;
+    constexpr explicit basic_simd_mask(@\libconcept{unsigned_integral}@ auto val) noexcept;
 
     // \ref{simd.mask.subscr}, \tcode{basic_simd_mask} subscript operators
     constexpr value_type operator[](@\exposid{simd-size-type}@) const;
@@ -19110,6 +19112,10 @@
     template<class U, class A>
       constexpr explicit(sizeof(U) != Bytes) operator basic_simd<U, A>() const noexcept;
 
+    // \ref{simd.mask.namedconv}, \tcode{basic_simd_mask} named type convertors
+    constexpr bitset<size()> to_bitset() const noexcept;
+    constexpr unsigned long long to_ullong() const;
+
     // \ref{simd.mask.binary}, \tcode{basic_simd_mask} binary operators
     friend constexpr basic_simd_mask
       operator&&(const basic_simd_mask&, const basic_simd_mask&) noexcept;
@@ -19242,6 +19248,31 @@
 \tcode{gen} is invoked exactly once for each $i$, in increasing order of $i$.
 \end{itemdescr}
 
+\begin{itemdecl}
+constexpr basic_simd_mask(const bitset<size()>& b) noexcept;
+\end{itemdecl}
+
+\begin{itemdescr}
+\pnum
+\effects
+Initializes the $i^\text{th}$ element with \tcode{b[$i$]} for all $i$ in the
+range \range{0}{size()}.
+\end{itemdescr}
+
+\begin{itemdecl}
+constexpr explicit basic_simd_mask(@\libconcept{unsigned_integral}@ auto val) noexcept;
+\end{itemdecl}
+
+\begin{itemdescr}
+\pnum
+\effects
+Initializes the first $M$ elements to the corresponding bit values in
+\tcode{val}, where $M$ is the smaller of \tcode{size()} and the number of bits in
+the value representation\iref{basic.types.general} of the type of \tcode{val}. If
+$M$ is less than \tcode{size()}, the remaining elements are initialized to
+zero.
+\end{itemdescr}
+
 \rSec3[simd.mask.subscr]{\tcode{basic_simd_mask} subscript operator}
 
 \begin{itemdecl}
@@ -19300,6 +19331,43 @@
 \tcode{static_cast<U>(operator[]($i$))}.
 \end{itemdescr}
 
+\rSec3[simd.mask.namedconv]{\tcode{basic_simd_mask} named conversion operators}
+
+\begin{itemdecl}
+constexpr bitset<size()> to_bitset() const noexcept;
+\end{itemdecl}
+
+\begin{itemdescr}
+\pnum
+\returns
+A \tcode{bitset<size()>} object where the $i^\text{th}$ element is initialized to
+\tcode{operator[]($i$)} for all $i$ in the range \range{0}{size()}.
+\end{itemdescr}
+
+\begin{itemdecl}
+constexpr unsigned long long to_ullong() const;
+\end{itemdecl}
+
+\begin{itemdescr}
+\pnum
+Let $N$ be the width of \tcode{unsigned long long}.
+
+\pnum
+\expects
+\begin{itemize}
+\item \tcode{size() <= $N$} is \tcode{true}, or
+\item for all $i$ in the range \range{$N$}{size()}, \tcode{operator[]($i$)} returns \tcode{false}.
+\end{itemize}
+
+\pnum
+\returns
+The integral value corresponding to the bits in \tcode{*this}.
+
+\pnum
+\throws
+Nothing.
+\end{itemdescr}
+
 \rSec2[simd.mask.nonmembers]{Non-member operations}
 
 \rSec3[simd.mask.binary]{\tcode{basic_simd_mask} binary operators}

source/support.tex

@@ -805,7 +805,7 @@
 #define @\defnlibxname{cpp_lib_shared_ptr_weak_type}@              201606L // also in \libheader{memory}
 #define @\defnlibxname{cpp_lib_shared_timed_mutex}@                201402L // also in \libheader{shared_mutex}
 #define @\defnlibxname{cpp_lib_shift}@                             202202L // also in \libheader{algorithm}
-#define @\defnlibxname{cpp_lib_simd}@                              202502L // also in \libheader{simd}
+#define @\defnlibxname{cpp_lib_simd}@                              202506L // also in \libheader{simd}
 #define @\defnlibxname{cpp_lib_simd_complex}@                      202502L // also in \libheader{simd}
 #define @\defnlibxname{cpp_lib_smart_ptr_for_overwrite}@           202002L // also in \libheader{memory}
 #define @\defnlibxname{cpp_lib_smart_ptr_owner_equality}@          202306L // also in \libheader{memory}