Add avx512 support for tranpose operator

Author: serge-sans-paille

include/xsimd/arch/xsimd_avx512f.hpp

@@ -25,6 +25,12 @@ namespace xsimd
     {
         using namespace types;
 
+        // fwd
+        template <class A>
+        XSIMD_INLINE void transpose(batch<uint16_t, A>* matrix_begin, batch<uint16_t, A>* matrix_end, requires_arch<generic>) noexcept;
+        template <class A>
+        XSIMD_INLINE void transpose(batch<uint8_t, A>* matrix_begin, batch<uint8_t, A>* matrix_end, requires_arch<generic>) noexcept;
+
         namespace detail
         {
             XSIMD_INLINE void split_avx512(__m512 val, __m256& low, __m256& high) noexcept
@@ -2010,6 +2016,79 @@ namespace xsimd
             return bitwise_cast<int16_t>(swizzle(bitwise_cast<uint16_t>(self), mask, avx512f {}));
         }
 
+        // transpose
+        template <class A>
+        XSIMD_INLINE void transpose(batch<uint16_t, A>* matrix_begin, batch<uint16_t, A>* matrix_end, requires_arch<avx512f>) noexcept
+        {
+            assert((matrix_end - matrix_begin == batch<uint16_t, A>::size) && "correctly sized matrix");
+            (void)matrix_end;
+            batch<uint16_t, avx2> tmp_lo0[16];
+            for (int i = 0; i < 16; ++i)
+                tmp_lo0[i] = _mm512_castsi512_si256(matrix_begin[i]);
+            transpose(tmp_lo0 + 0, tmp_lo0 + 16, avx2 {});
+
+            batch<uint16_t, avx2> tmp_hi0[16];
+            for (int i = 0; i < 16; ++i)
+                tmp_hi0[i] = _mm512_castsi512_si256(matrix_begin[16 + i]);
+            transpose(tmp_hi0 + 0, tmp_hi0 + 16, avx2 {});
+
+            batch<uint16_t, avx2> tmp_lo1[16];
+            for (int i = 0; i < 16; ++i)
+                tmp_lo1[i] = _mm512_extracti64x4_epi64(matrix_begin[i], 1);
+            transpose(tmp_lo1 + 0, tmp_lo1 + 16, avx2 {});
+
+            batch<uint16_t, avx2> tmp_hi1[16];
+            for (int i = 0; i < 16; ++i)
+                tmp_hi1[i] = _mm512_extracti64x4_epi64(matrix_begin[16 + i], 1);
+            transpose(tmp_hi1 + 0, tmp_hi1 + 16, avx2 {});
+
+            for (int i = 0; i < 16; ++i)
+                matrix_begin[i] = detail::merge_avx(tmp_lo0[i], tmp_hi0[i]);
+            for (int i = 0; i < 16; ++i)
+                matrix_begin[i + 16] = detail::merge_avx(tmp_lo1[i], tmp_hi1[i]);
+        }
+        template <class A>
+        XSIMD_INLINE void transpose(batch<int16_t, A>* matrix_begin, batch<int16_t, A>* matrix_end, requires_arch<avx512f>) noexcept
+        {
+            return transpose(reinterpret_cast<batch<uint16_t, A>*>(matrix_begin), reinterpret_cast<batch<uint16_t, A>*>(matrix_end), A {});
+        }
+
+        template <class A>
+        XSIMD_INLINE void transpose(batch<uint8_t, A>* matrix_begin, batch<uint8_t, A>* matrix_end, requires_arch<avx512f>) noexcept
+        {
+            assert((matrix_end - matrix_begin == batch<uint8_t, A>::size) && "correctly sized matrix");
+            (void)matrix_end;
+            batch<uint8_t, avx2> tmp_lo0[32];
+            for (int i = 0; i < 32; ++i)
+                tmp_lo0[i] = _mm512_castsi512_si256(matrix_begin[i]);
+            transpose(tmp_lo0 + 0, tmp_lo0 + 32, avx2 {});
+
+            batch<uint8_t, avx2> tmp_hi0[32];
+            for (int i = 0; i < 32; ++i)
+                tmp_hi0[i] = _mm512_castsi512_si256(matrix_begin[32 + i]);
+            transpose(tmp_hi0 + 0, tmp_hi0 + 32, avx2 {});
+
+            batch<uint8_t, avx2> tmp_lo1[32];
+            for (int i = 0; i < 32; ++i)
+                tmp_lo1[i] = _mm512_extracti64x4_epi64(matrix_begin[i], 1);
+            transpose(tmp_lo1 + 0, tmp_lo1 + 32, avx2 {});
+
+            batch<uint8_t, avx2> tmp_hi1[32];
+            for (int i = 0; i < 32; ++i)
+                tmp_hi1[i] = _mm512_extracti64x4_epi64(matrix_begin[32 + i], 1);
+            transpose(tmp_hi1 + 0, tmp_hi1 + 32, avx2 {});
+
+            for (int i = 0; i < 32; ++i)
+                matrix_begin[i] = detail::merge_avx(tmp_lo0[i], tmp_hi0[i]);
+            for (int i = 0; i < 32; ++i)
+                matrix_begin[i + 32] = detail::merge_avx(tmp_lo1[i], tmp_hi1[i]);
+        }
+        template <class A>
+        XSIMD_INLINE void transpose(batch<int8_t, A>* matrix_begin, batch<int8_t, A>* matrix_end, requires_arch<avx512f>) noexcept
+        {
+            return transpose(reinterpret_cast<batch<uint8_t, A>*>(matrix_begin), reinterpret_cast<batch<uint8_t, A>*>(matrix_end), A {});
+        }
+
         // trunc
         template <class A>
         XSIMD_INLINE batch<float, A>