From 87729ea39ff22e0f949ca64ec372f381d9e39708 Mon Sep 17 00:00:00 2001
From: Antonio Sanchez <cantonios@google.com>
Date: Wed, 24 Mar 2021 10:12:02 -0700
Subject: Eliminate `round_impl` double-promotion warnings for c++03.

---
 Eigen/src/Core/MathFunctions.h         | 38 +++++++++++++++++++++++++++-------
 Eigen/src/Core/arch/Default/BFloat16.h |  7 +++++--
 Eigen/src/Core/arch/Default/Half.h     |  9 +++++---
 3 files changed, 42 insertions(+), 12 deletions(-)

diff --git a/Eigen/src/Core/MathFunctions.h b/Eigen/src/Core/MathFunctions.h
index c8db56e9b..29201214f 100644
--- a/Eigen/src/Core/MathFunctions.h
+++ b/Eigen/src/Core/MathFunctions.h
@@ -485,14 +485,31 @@ struct round_impl
     EIGEN_STATIC_ASSERT((!NumTraits<Scalar>::IsComplex), NUMERIC_TYPE_MUST_BE_REAL)
 #if EIGEN_HAS_CXX11_MATH
     EIGEN_USING_STD(round);
+#endif
     return Scalar(round(x));
-#elif EIGEN_HAS_C99_MATH
-    if (is_same<Scalar, float>::value) {
-      return Scalar(::roundf(x));
-    } else {
-      return Scalar(round(x));
-    }
+  }
+};
+
+#if !EIGEN_HAS_CXX11_MATH
+#if EIGEN_HAS_C99_MATH
+// Use ::roundf for float.
+template<>
+struct round_impl<float> {
+  EIGEN_DEVICE_FUNC
+  static inline float run(const float& x)
+  {
+    return ::roundf(x);
+  }
+};
 #else
+template<typename Scalar>
+struct round_using_floor_ceil_impl
+{
+  EIGEN_DEVICE_FUNC
+  static inline Scalar run(const Scalar& x)
+  {
+    EIGEN_STATIC_ASSERT((!NumTraits<Scalar>::IsComplex), NUMERIC_TYPE_MUST_BE_REAL)
+    // Without C99 round/roundf, resort to floor/ceil.
     EIGEN_USING_STD(floor);
     EIGEN_USING_STD(ceil);
     // If not enough precision to resolve a decimal at all, return the input.
@@ -502,10 +519,17 @@ struct round_impl
       return x;
     }
     return (x > Scalar(0)) ? Scalar(floor(x + Scalar(0.5))) : Scalar(ceil(x - Scalar(0.5)));
-#endif
   }
 };
 
+template<>
+struct round_impl<float> : round_using_floor_ceil_impl<float> {};
+
+template<>
+struct round_impl<double> : round_using_floor_ceil_impl<double> {};
+#endif // EIGEN_HAS_C99_MATH
+#endif // !EIGEN_HAS_CXX11_MATH
+
 template<typename Scalar>
 struct round_retval
 {
diff --git a/Eigen/src/Core/arch/Default/BFloat16.h b/Eigen/src/Core/arch/Default/BFloat16.h
index 3c0cd39df..aac60f15c 100644
--- a/Eigen/src/Core/arch/Default/BFloat16.h
+++ b/Eigen/src/Core/arch/Default/BFloat16.h
@@ -562,11 +562,14 @@ EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 atanh(const bfloat16& a) {
 EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 floor(const bfloat16& a) {
   return bfloat16(::floorf(float(a)));
 }
+EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 ceil(const bfloat16& a) {
+  return bfloat16(::ceilf(float(a)));
+}
 EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 rint(const bfloat16& a) {
   return bfloat16(::rintf(float(a)));
 }
-EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 ceil(const bfloat16& a) {
-  return bfloat16(::ceilf(float(a)));
+EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 round(const bfloat16& a) {
+  return bfloat16(::roundf(float(a)));
 }
 EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 fmod(const bfloat16& a, const bfloat16& b) {
   return bfloat16(::fmodf(float(a), float(b)));
diff --git a/Eigen/src/Core/arch/Default/Half.h b/Eigen/src/Core/arch/Default/Half.h
index 56ff7cec3..9f8e8cc1e 100644
--- a/Eigen/src/Core/arch/Default/Half.h
+++ b/Eigen/src/Core/arch/Default/Half.h
@@ -718,9 +718,6 @@ EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half floor(const half& a) {
   return half(::floorf(float(a)));
 #endif
 }
-EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half rint(const half& a) {
-  return half(::rintf(float(a)));
-}
 EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half ceil(const half& a) {
 #if (EIGEN_CUDA_SDK_VER >= 80000 && defined EIGEN_CUDA_ARCH && EIGEN_CUDA_ARCH >= 300) || \
   defined(EIGEN_HIP_DEVICE_COMPILE)
@@ -729,6 +726,12 @@ EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half ceil(const half& a) {
   return half(::ceilf(float(a)));
 #endif
 }
+EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half rint(const half& a) {
+  return half(::rintf(float(a)));
+}
+EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half round(const half& a) {
+  return half(::roundf(float(a)));
+}
 EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half fmod(const half& a, const half& b) {
   return half(::fmodf(float(a), float(b)));
 }
-- 
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