From 132f281f501380faeba1b5b1fe7e4f237099c2a3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Antonio=20S=C3=A1nchez?= <cantonios@google.com>
Date: Sat, 14 Sep 2024 01:31:21 +0000
Subject: [PATCH] Fix generic ceil for SSE2.

---
 Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h b/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
index 0e841582a..5bce19464 100644
--- a/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
+++ b/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
@@ -2598,11 +2598,14 @@ template <typename Packet>
 EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Packet generic_ceil(const Packet& a) {
   using Scalar = typename unpacket_traits<Packet>::type;
   const Packet cst_1 = pset1<Packet>(Scalar(1));
+  const Packet sign_mask = pset1<Packet>(static_cast<Scalar>(-0.0));
   Packet rint_a = generic_rint(a);
   // if rint(a) < a, then rint(a) == floor(a)
   Packet mask = pcmp_lt(rint_a, a);
   Packet offset = pand(cst_1, mask);
   Packet result = padd(rint_a, offset);
+  // Signed zero must remain signed (e.g. ceil(-0.02) == -0).
+  result = por(result, pand(sign_mask, a));
   return result;
 }