From e4f58816d930894b1f5ec0cac177fdbd37f2c6a2 Mon Sep 17 00:00:00 2001
From: Rasmus Munk Larsen <rmlarsen@google.com>
Date: Tue, 7 Feb 2023 21:36:44 -0800
Subject: [PATCH] Get rid of custom implementation of equal_to and
 not_equal_no. No longer needed with c+14.

---
 Eigen/src/Core/functors/StlFunctors.h    | 31 ------------------------
 Eigen/src/plugins/MatrixCwiseBinaryOps.h |  8 +++---
 2 files changed, 4 insertions(+), 35 deletions(-)

diff --git a/Eigen/src/Core/functors/StlFunctors.h b/Eigen/src/Core/functors/StlFunctors.h
index 5971075dd..b8b842bcc 100644
--- a/Eigen/src/Core/functors/StlFunctors.h
+++ b/Eigen/src/Core/functors/StlFunctors.h
@@ -13,29 +13,6 @@
 #include "../InternalHeaderCheck.h"
 
 namespace Eigen {
-
-// Portable replacements for certain functors.
-namespace numext {
-
-template<typename T = void>
-struct equal_to {
-  typedef bool result_type;
-  EIGEN_DEVICE_FUNC bool operator()(const T& lhs, const T& rhs) const {
-    return lhs == rhs;
-  }
-};
-
-template<typename T = void>
-struct not_equal_to {
-  typedef bool result_type;
-  EIGEN_DEVICE_FUNC bool operator()(const T& lhs, const T& rhs) const {
-    return lhs != rhs;
-  }
-};
-
-}
-
-
 namespace internal {
 
 // default functor traits for STL functors:
@@ -92,18 +69,10 @@ template<typename T>
 struct functor_traits<std::equal_to<T> >
 { enum { Cost = 1, PacketAccess = false }; };
 
-template<typename T>
-struct functor_traits<numext::equal_to<T> >
-  : functor_traits<std::equal_to<T> > {};
-
 template<typename T>
 struct functor_traits<std::not_equal_to<T> >
 { enum { Cost = 1, PacketAccess = false }; };
 
-template<typename T>
-struct functor_traits<numext::not_equal_to<T> >
-  : functor_traits<std::not_equal_to<T> > {};
-
 #if (EIGEN_COMP_CXXVER < 17)
 // std::unary_negate is deprecated since c++17 and will be removed in c++20
 template<typename T>
diff --git a/Eigen/src/plugins/MatrixCwiseBinaryOps.h b/Eigen/src/plugins/MatrixCwiseBinaryOps.h
index 46fe08ce8..5aed0f8d0 100644
--- a/Eigen/src/plugins/MatrixCwiseBinaryOps.h
+++ b/Eigen/src/plugins/MatrixCwiseBinaryOps.h
@@ -39,10 +39,10 @@ cwiseProduct(const EIGEN_CURRENT_STORAGE_BASE_CLASS<OtherDerived> &other) const
   */
 template<typename OtherDerived>
 EIGEN_DEVICE_FUNC
-inline const CwiseBinaryOp<numext::equal_to<Scalar>, const Derived, const OtherDerived>
+inline const CwiseBinaryOp<std::equal_to<Scalar>, const Derived, const OtherDerived>
 cwiseEqual(const EIGEN_CURRENT_STORAGE_BASE_CLASS<OtherDerived> &other) const
 {
-  return CwiseBinaryOp<numext::equal_to<Scalar>, const Derived, const OtherDerived>(derived(), other.derived());
+  return CwiseBinaryOp<std::equal_to<Scalar>, const Derived, const OtherDerived>(derived(), other.derived());
 }
 
 /** \returns an expression of the coefficient-wise != operator of *this and \a other
@@ -59,10 +59,10 @@ cwiseEqual(const EIGEN_CURRENT_STORAGE_BASE_CLASS<OtherDerived> &other) const
   */
 template<typename OtherDerived>
 EIGEN_DEVICE_FUNC
-inline const CwiseBinaryOp<numext::not_equal_to<Scalar>, const Derived, const OtherDerived>
+inline const CwiseBinaryOp<std::not_equal_to<Scalar>, const Derived, const OtherDerived>
 cwiseNotEqual(const EIGEN_CURRENT_STORAGE_BASE_CLASS<OtherDerived> &other) const
 {
-  return CwiseBinaryOp<numext::not_equal_to<Scalar>, const Derived, const OtherDerived>(derived(), other.derived());
+  return CwiseBinaryOp<std::not_equal_to<Scalar>, const Derived, const OtherDerived>(derived(), other.derived());
 }
 
 /** \returns an expression of the coefficient-wise min of *this and \a other