fixed clang warnings about alignment change and floating point precision

Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h

diff --git a/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h b/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
index 5f2a130..d3c314b 100644
--- a/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
+++ b/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
@@ -494,7 +494,7 @@
 Packet pexp_double(const Packet _x)
 {
   Packet x = _x;
-  const Packet cst_zero = pset1<Packet>(0.0f);
+  const Packet cst_zero = pset1<Packet>(0.0);
   const Packet cst_1 = pset1<Packet>(1.0);
   const Packet cst_2 = pset1<Packet>(2.0);
   const Packet cst_half = pset1<Packet>(0.5);

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

diff --git a/Eigen/src/Core/arch/SSE/Complex.h b/Eigen/src/Core/arch/SSE/Complex.h
index 61e9406..60308ce 100644
--- a/Eigen/src/Core/arch/SSE/Complex.h
+++ b/Eigen/src/Core/arch/SSE/Complex.h
@@ -137,7 +137,7 @@
 
 template<> EIGEN_STRONG_INLINE std::complex<float>  pfirst<Packet2cf>(const Packet2cf& a)
 {
-  std::complex<float> res;
+  alignas(alignof(__m64)) std::complex<float> res;
   _mm_storel_pi((__m64*)&res, a.v);
   return res;
 }