guix/gnu/packages/patches/eigen-fix-strict-aliasing-bug.patch

From f046e326d9e30772725d8fb26dc33328e418d9d3 Mon Sep 17 00:00:00 2001
From: Antonio Sanchez <cantonios@google.com>
Date: Fri, 17 Sep 2021 12:49:01 -0700
Subject: [PATCH] Fix strict aliasing bug causing product_small failure.

Packet loading is skipped due to aliasing violation, leading to nullopt matrix
multiplication.

Fixes #2327.


(cherry picked from commit 3c724c44cff3f9e2e9e35351abff0b5c022b320d)
---
 Eigen/src/Core/arch/AVX/Complex.h    |  4 +++-
 Eigen/src/Core/arch/AVX512/Complex.h |  4 +++-
 Eigen/src/Core/arch/SSE/Complex.h    | 11 +++--------
 3 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/Eigen/src/Core/arch/AVX/Complex.h b/Eigen/src/Core/arch/AVX/Complex.h
index ab7bd6c65..e9096c0a1 100644
--- a/Eigen/src/Core/arch/AVX/Complex.h
+++ b/Eigen/src/Core/arch/AVX/Complex.h
@@ -99,7 +99,9 @@ template<> EIGEN_STRONG_INLINE Packet4cf ploadu<Packet4cf>(const std::complex<fl
 
 template<> EIGEN_STRONG_INLINE Packet4cf pset1<Packet4cf>(const std::complex<float>& from)
 {
-  return Packet4cf(_mm256_castpd_ps(_mm256_broadcast_sd((const double*)(const void*)&from)));
+  const float re = std::real(from);
+  const float im = std::imag(from);
+  return Packet4cf(_mm256_set_ps(im, re, im, re, im, re, im, re));
 }
 
 template<> EIGEN_STRONG_INLINE Packet4cf ploaddup<Packet4cf>(const std::complex<float>* from)
diff --git a/Eigen/src/Core/arch/AVX512/Complex.h b/Eigen/src/Core/arch/AVX512/Complex.h
index 49c72b3f1..074253859 100644
--- a/Eigen/src/Core/arch/AVX512/Complex.h
+++ b/Eigen/src/Core/arch/AVX512/Complex.h
@@ -97,7 +97,9 @@ template<> EIGEN_STRONG_INLINE Packet8cf ploadu<Packet8cf>(const std::complex<fl
 
 template<> EIGEN_STRONG_INLINE Packet8cf pset1<Packet8cf>(const std::complex<float>& from)
 {
-  return Packet8cf(_mm512_castpd_ps(pload1<Packet8d>((const double*)(const void*)&from)));
+  const float re = std::real(from);
+  const float im = std::imag(from);
+  return Packet8cf(_mm512_set_ps(im, re, im, re, im, re, im, re, im, re, im, re, im, re, im, re));
 }
 
 template<> EIGEN_STRONG_INLINE Packet8cf ploaddup<Packet8cf>(const std::complex<float>* from)
diff --git a/Eigen/src/Core/arch/SSE/Complex.h b/Eigen/src/Core/arch/SSE/Complex.h
index 8fe22da46..215bfd7bb 100644
--- a/Eigen/src/Core/arch/SSE/Complex.h
+++ b/Eigen/src/Core/arch/SSE/Complex.h
@@ -106,14 +106,9 @@ template<> EIGEN_STRONG_INLINE Packet2cf ploadu<Packet2cf>(const std::complex<fl
 
 template<> EIGEN_STRONG_INLINE Packet2cf pset1<Packet2cf>(const std::complex<float>&  from)
 {
-  Packet2cf res;
-#ifdef EIGEN_VECTORIZE_SSE3
-  res.v = _mm_castpd_ps(_mm_loaddup_pd(reinterpret_cast<double const*>(&from)));
-#else
-  res.v = _mm_castpd_ps(_mm_load_sd(reinterpret_cast<double const*>(&from)));
-  res.v = _mm_movelh_ps(res.v, res.v);
-#endif
-  return res;
+  const float re = std::real(from);
+  const float im = std::imag(from);
+  return Packet2cf(_mm_set_ps(im, re, im, re));
 }
 
 template<> EIGEN_STRONG_INLINE Packet2cf ploaddup<Packet2cf>(const std::complex<float>* from) { return pset1<Packet2cf>(*from); }
-- 
2.37.0