Add pinsertfirst function and implement pinsertlast for complex on SSE/AVX.

Eigen/src/Core/GenericPacketMath.h

@@ -558,7 +558,21 @@ pblend(const Selector<unpacket_traits<Packet>::size>& ifPacket, const Packet& th
   return ifPacket.select[0] ? thenPacket : elsePacket;
 }
 
-/** \internal \returns \a a with last coefficients replaced by the scalar b */
+/** \internal \returns \a a with the first coefficient replaced by the scalar b */
+template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
+pinsertfirst(const Packet& a, typename unpacket_traits<Packet>::type b)
+{
+  // Default implementation based on pblend.
+  // It must be specialized for higher performance.
+  Selector<unpacket_traits<Packet>::size> mask;
+  mask.select[0] = true;
+  // This for loop should be optimized away by the compiler.
+  for(Index i=1; i<unpacket_traits<Packet>::size; ++i)
+    mask.select[i] = false;
+  return pblend(mask, pset1<Packet>(b), a);
+}
+
+/** \internal \returns \a a with the last coefficient replaced by the scalar b */
 template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
 pinsertlast(const Packet& a, typename unpacket_traits<Packet>::type b)
 {

Eigen/src/Core/arch/AVX/Complex.h

@@ -456,6 +456,26 @@ ptranspose(PacketBlock<Packet2cd,2>& kernel) {
  kernel.packet[0].v = tmp;
 }
 
+template<> EIGEN_STRONG_INLINE Packet4cf pinsertfirst(const Packet4cf& a, std::complex<float> b)
+{
+  return Packet4cf(_mm256_blend_ps(a.v,pset1<Packet4cf>(b).v,1|2));
+}
+
+template<> EIGEN_STRONG_INLINE Packet2cd pinsertfirst(const Packet2cd& a, std::complex<double> b)
+{
+  return Packet2cd(_mm256_blend_pd(a.v,pset1<Packet2cd>(b).v,1|2));
+}
+
+template<> EIGEN_STRONG_INLINE Packet4cf pinsertlast(const Packet4cf& a, std::complex<float> b)
+{
+  return Packet4cf(_mm256_blend_ps(a.v,pset1<Packet4cf>(b).v,(1<<7)|(1<<6)));
+}
+
+template<> EIGEN_STRONG_INLINE Packet2cd pinsertlast(const Packet2cd& a, std::complex<double> b)
+{
+  return Packet2cd(_mm256_blend_pd(a.v,pset1<Packet2cd>(b).v,(1<<3)|(1<<2)));
+}
+
 } // end namespace internal
 
 } // end namespace Eigen

Eigen/src/Core/arch/AVX/PacketMath.h

@@ -604,6 +604,16 @@ template<> EIGEN_STRONG_INLINE Packet4d pblend(const Selector<4>& ifPacket, cons
   return _mm256_blendv_pd(thenPacket, elsePacket, false_mask);
 }
 
+template<> EIGEN_STRONG_INLINE Packet8f pinsertfirst(const Packet8f& a, float b)
+{
+  return _mm256_blend_ps(a,pset1<Packet8f>(b),1);
+}
+
+template<> EIGEN_STRONG_INLINE Packet4d pinsertfirst(const Packet4d& a, double b)
+{
+  return _mm256_blend_pd(a,pset1<Packet4d>(b),1);
+}
+
 template<> EIGEN_STRONG_INLINE Packet8f pinsertlast(const Packet8f& a, float b)
 {
   return _mm256_blend_ps(a,pset1<Packet8f>(b),(1<<7));

Eigen/src/Core/arch/SSE/Complex.h

@@ -476,6 +476,26 @@ template<>  EIGEN_STRONG_INLINE Packet2cf pblend(const Selector<2>& ifPacket, co
   return Packet2cf(_mm_castpd_ps(result));
 }
 
+template<> EIGEN_STRONG_INLINE Packet2cf pinsertfirst(const Packet2cf& a, std::complex<float> b)
+{
+  return Packet2cf(_mm_loadl_pi(a.v, reinterpret_cast<const __m64*>(&b)));
+}
+
+template<> EIGEN_STRONG_INLINE Packet1cd pinsertfirst(const Packet1cd&, std::complex<double> b)
+{
+  return pset1<Packet1cd>(b);
+}
+
+template<> EIGEN_STRONG_INLINE Packet2cf pinsertlast(const Packet2cf& a, std::complex<float> b)
+{
+  return Packet2cf(_mm_loadh_pi(a.v, reinterpret_cast<const __m64*>(&b)));
+}
+
+template<> EIGEN_STRONG_INLINE Packet1cd pinsertlast(const Packet1cd&, std::complex<double> b)
+{
+  return pset1<Packet1cd>(b);
+}
+
 } // end namespace internal
 
 } // end namespace Eigen

Eigen/src/Core/arch/SSE/PacketMath.h

@@ -818,6 +818,24 @@ template<> EIGEN_STRONG_INLINE Packet2d pblend(const Selector<2>& ifPacket, cons
 #endif
 }
 
+template<> EIGEN_STRONG_INLINE Packet4f pinsertfirst(const Packet4f& a, float b)
+{
+#ifdef EIGEN_VECTORIZE_SSE4_1
+  return _mm_blend_ps(a,pset1<Packet4f>(b),1);
+#else
+  return _mm_move_ss(a, _mm_load_ss(&b));
+#endif
+}
+
+template<> EIGEN_STRONG_INLINE Packet2d pinsertfirst(const Packet2d& a, double b)
+{
+#ifdef EIGEN_VECTORIZE_SSE4_1
+  return _mm_blend_pd(a,pset1<Packet2d>(b),1);
+#else
+  return _mm_move_sd(a, _mm_load_sd(&b));
+#endif
+}
+
 template<> EIGEN_STRONG_INLINE Packet4f pinsertlast(const Packet4f& a, float b)
 {
 #ifdef EIGEN_VECTORIZE_SSE4_1

test/packetmath.cpp

@@ -16,6 +16,12 @@
 #endif
 // using namespace Eigen;
 
+#ifdef EIGEN_VECTORIZE_SSE
+const bool g_vectorize_sse = true;
+#else
+const bool g_vectorize_sse = false;
+#endif
+
 namespace Eigen {
 namespace internal {
 template<typename T> T negate(const T& x) { return -x; }
@@ -290,7 +296,17 @@ template<typename Scalar> void packetmath()
     }
   }
 
-  if (PacketTraits::HasBlend) {
+  if (PacketTraits::HasBlend || g_vectorize_sse) {
+    // pinsertfirst
+    for (int i=0; i<PacketSize; ++i)
+      ref[i] = data1[i];
+    Scalar s = internal::random<Scalar>();
+    ref[0] = s;
+    internal::pstore(data2, internal::pinsertfirst(internal::pload<Packet>(data1),s));
+    VERIFY(areApprox(ref, data2, PacketSize) && "internal::pinsertfirst");
+  }
+
+  if (PacketTraits::HasBlend || g_vectorize_sse) {
     // pinsertlast
     for (int i=0; i<PacketSize; ++i)
       ref[i] = data1[i];