From 4d1d14e069c53866a3a08fba155920ff9ccd29a6 Mon Sep 17 00:00:00 2001
From: Chip Kerchner <chip.kerchner@ibm.com>
Date: Wed, 8 May 2024 22:39:27 +0000
Subject: [PATCH] Change predux on PowerPC for Packet4i to NOT saturate the sum
 of the elements (like other architectures).

---
 Eigen/src/Core/arch/AltiVec/PacketMath.h | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/Eigen/src/Core/arch/AltiVec/PacketMath.h b/Eigen/src/Core/arch/AltiVec/PacketMath.h
index 4c92e05b0..6c472cdf1 100644
--- a/Eigen/src/Core/arch/AltiVec/PacketMath.h
+++ b/Eigen/src/Core/arch/AltiVec/PacketMath.h
@@ -2437,13 +2437,11 @@ EIGEN_STRONG_INLINE float predux<Packet4f>(const Packet4f& a) {
 
 template <>
 EIGEN_STRONG_INLINE int predux<Packet4i>(const Packet4i& a) {
-  Packet4i sum;
-  sum = vec_sums(a, p4i_ZERO);
-#ifdef _BIG_ENDIAN
-  sum = vec_sld(sum, p4i_ZERO, 12);
-#else
-  sum = vec_sld(p4i_ZERO, sum, 4);
-#endif
+  Packet4i b, sum;
+  b = vec_sld(a, a, 8);
+  sum = a + b;
+  b = vec_sld(sum, sum, 4);
+  sum += b;
   return pfirst(sum);
 }