Vector: add constructor taking an element reference

Fixes #256
VcDevel · Aug 12, 2021 · 348637b · 348637b
1 parent 93ac07e
commit 348637b
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diff --git a/Vc/avx/vector.h b/Vc/avx/vector.h
@@ -160,6 +160,8 @@ template <typename T> class Vector<T, VectorAbi::Avx>
             explicit Vector(U &&x) Vc_INTRINSIC_R;
 #endif
 
+        Vc_INTRINSIC explicit Vector(reference a) : Vector(static_cast<EntryType>(a)) {}
+
         ///////////////////////////////////////////////////////////////////////////////////////////
         // broadcast
         Vc_INTRINSIC Vector(EntryType a) : d(Detail::avx_broadcast(a)) {}

diff --git a/Vc/common/vector.h b/Vc/common/vector.h
@@ -289,6 +289,7 @@ template<typename T, typename Abi = VectorAbi::Best<T>> class Vector
     template <typename U>
     inline Vector(U a, enable_if<std::is_same<U, int>::value &&
                                  !std::is_same<U, EntryType>::value> = nullarg);
+    inline explicit Vector(reference a);
     ///@}
 
     /**

diff --git a/Vc/scalar/vector.h b/Vc/scalar/vector.h
@@ -105,6 +105,8 @@ template <typename T> class Vector<T, VectorAbi::Scalar>
         }
 #endif
 
+        Vc_INTRINSIC explicit Vector(reference a) : Vector(static_cast<EntryType>(a)) {}
+
         ///////////////////////////////////////////////////////////////////////////////////////////
         // broadcast
         Vc_INTRINSIC Vector(EntryType a) : m_data(a) {}

diff --git a/Vc/sse/vector.h b/Vc/sse/vector.h
@@ -135,6 +135,8 @@ template <typename T> class Vector<T, VectorAbi::Sse>
         {
         }
 
+        Vc_INTRINSIC explicit Vector(reference a) : Vector(static_cast<EntryType>(a)) {}
+
 #include "../common/loadinterface.h"
 #include "../common/storeinterface.h"
 

diff --git a/tests/casts.cpp b/tests/casts.cpp
@@ -392,6 +392,17 @@ TEST(fullConversion)/*{{{*/
 }/*}}}*/
 #endif // Vc_DEFAULT_TYPES
 
+TEST(referenceConstruction)
+{
+    float_v a = float_v::Random();
+
+    Vc::float_v r = a[2];
+
+    for (size_t i = 0; i < float_v::Size; ++i) {
+        COMPARE(r[i], static_cast<float>(a[2])) << "i = " << i;
+    }
+}
+
 #if 0
 /*{{{*/
 template<typename T> constexpr bool may_overflow() { return std::is_integral<T>::value && std::is_unsigned<T>::value; }