From 5e8edd21863b8321fc6b9c82322e6cc8cfc47c14 Mon Sep 17 00:00:00 2001
From: Antonio Sanchez <cantonios@google.com>
Date: Thu, 13 Mar 2025 22:23:45 -0700
Subject: [PATCH] Fix undefined behavior in PPC load.

VSX vec_xl is Causing a bunch of test failures and failing `-fsanitize=undefined` with g++.
Removing the instruction allows tests to pass and eliminates the warning.
---
 Eigen/src/Core/arch/AltiVec/PacketMath.h | 16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/Eigen/src/Core/arch/AltiVec/PacketMath.h b/Eigen/src/Core/arch/AltiVec/PacketMath.h
index 27f61a49b..9022a71e0 100755
--- a/Eigen/src/Core/arch/AltiVec/PacketMath.h
+++ b/Eigen/src/Core/arch/AltiVec/PacketMath.h
@@ -224,29 +224,25 @@ inline std::ostream & operator <<(std::ostream & s, const Packet4ui & v)
   return s;
 }
 
-template <typename Packet>
-EIGEN_STRONG_INLINE Packet pload_common(const __UNPACK_TYPE__(Packet)* from)
+template <typename Packet, typename Scalar>
+EIGEN_STRONG_INLINE Packet pload_common(const Scalar* from)
 {
   // some versions of GCC throw "unused-but-set-parameter".
   // ignoring these warnings for now.
   EIGEN_UNUSED_VARIABLE(from);
   EIGEN_DEBUG_ALIGNED_LOAD
-#ifdef __VSX__
-  return vec_xl(0, const_cast<__UNPACK_TYPE__(Packet)*>(from));
-#else
   return vec_ld(0, from);
-#endif
 }
 
 // Need to define them first or we get specialization after instantiation errors
 template<> EIGEN_STRONG_INLINE Packet4f pload<Packet4f>(const float* from)
 {
-  return pload_common<Packet4f>(from);
+  return pload_common<Packet4f, float>(from);
 }
 
 template<> EIGEN_STRONG_INLINE Packet4i pload<Packet4i>(const int*     from)
 {
-  return pload_common<Packet4i>(from);
+  return pload_common<Packet4i, int>(from);
 }
 
 template <typename Packet>
@@ -455,15 +451,11 @@ template<> EIGEN_STRONG_INLINE Packet4f pfloor<Packet4f>(const Packet4f& a) { re
 template<typename Packet> EIGEN_STRONG_INLINE Packet ploadu_common(const __UNPACK_TYPE__(Packet)* from)
 {
   EIGEN_DEBUG_UNALIGNED_LOAD
-#ifdef __VSX__
-  return vec_xl(0, const_cast<__UNPACK_TYPE__(Packet)*>(from));
-#else
   Packet16uc mask = vec_lvsl(0, from);                 // create the permute mask
   Packet16uc MSQ = vec_ld(0, (unsigned char *)from);   // most significant quadword
   Packet16uc LSQ = vec_ld(15, (unsigned char *)from);  // least significant quadword
   //TODO: Add static_cast here
   return (Packet) vec_perm(MSQ, LSQ, mask);            // align the data
-#endif
 }
 
 template<> EIGEN_STRONG_INLINE Packet4f ploadu<Packet4f>(const float* from)