Addendum to bug 859: pexp(NaN) for double did not return NaN, also, plog(NaN) did not return NaN.

psqrt(NaN) and psqrt(-1) shall return NaN if EIGEN_FAST_MATH==0

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

@@ -52,7 +52,7 @@ Packet4f plog<Packet4f>(const Packet4f& _x)
 
   Packet4i emm0;
 
-  Packet4f invalid_mask = _mm_cmplt_ps(x, _mm_setzero_ps());
+  Packet4f invalid_mask = _mm_cmpnge_ps(x, _mm_setzero_ps()); // not greater equal is true if x is NaN
   Packet4f iszero_mask = _mm_cmpeq_ps(x, _mm_setzero_ps());
 
   x = pmax(x, p4f_min_norm_pos);  /* cut off denormalized stuff */
@@ -239,7 +239,7 @@ Packet2d pexp<Packet2d>(const Packet2d& _x)
   emm0 = _mm_add_epi32(emm0, p4i_1023_0);
   emm0 = _mm_slli_epi32(emm0, 20);
   emm0 = _mm_shuffle_epi32(emm0, _MM_SHUFFLE(1,2,0,3));
-  return pmul(x, _mm_castsi128_pd(emm0));
+  return pmax(pmul(x, Packet2d(_mm_castsi128_pd(emm0))), _x);
 }
 
 /* evaluation of 4 sines at onces, using SSE2 intrinsics.

test/packetmath.cpp

@@ -253,8 +253,22 @@ template<typename Scalar> void packetmath_real()
   }
   if(internal::random<float>(0,1)<0.1)
     data1[internal::random<int>(0, PacketSize)] = 0;
-  CHECK_CWISE1_IF(internal::packet_traits<Scalar>::HasLog, std::log, internal::plog);
   CHECK_CWISE1_IF(internal::packet_traits<Scalar>::HasSqrt, std::sqrt, internal::psqrt);
+  CHECK_CWISE1_IF(internal::packet_traits<Scalar>::HasLog, std::log, internal::plog);
+  {
+    data1[0] = std::numeric_limits<Scalar>::quiet_NaN();
+    packet_helper<internal::packet_traits<Scalar>::HasLog,Packet> h;
+    h.store(data2, internal::plog(h.load(data1)));
+    VERIFY(isNaN(data2[0]));
+    data1[0] = -1.0f;
+    h.store(data2, internal::plog(h.load(data1)));
+    VERIFY(isNaN(data2[0]));
+#if !EIGEN_FAST_MATH
+    h.store(data2, internal::psqrt(h.load(data1)));
+    VERIFY(isNaN(data2[0]));
+    VERIFY(isNaN(data2[1]));
+#endif
+  }
 }
 
 template<typename Scalar> void packetmath_notcomplex()