From 0339502a4feb6340f1e9f6f6ca8b3ef4d263f366 Mon Sep 17 00:00:00 2001
From: Deanna Hood <deanna.m.hood@gmail.com>
Date: Mon, 20 Apr 2015 13:14:06 -0400
Subject: Only use std::isnan and std::isinf if they are available

---
 Eigen/src/Core/MathFunctions.h | 54 ++++++++++++++++++++++++++++++------------
 Eigen/src/Core/util/Macros.h   |  8 +++++++
 2 files changed, 47 insertions(+), 15 deletions(-)

(limited to 'Eigen/src/Core')

diff --git a/Eigen/src/Core/MathFunctions.h b/Eigen/src/Core/MathFunctions.h
index 734a5e373..3bbebb345 100644
--- a/Eigen/src/Core/MathFunctions.h
+++ b/Eigen/src/Core/MathFunctions.h
@@ -790,14 +790,26 @@ bool (isfinite)(const std::complex<T>& x)
   using std::imag;
   return isfinite(real(x)) && isfinite(imag(x));
 }
-
-template<typename T>
-EIGEN_DEVICE_FUNC
-bool (isNaN)(const T& x)
-{
-  using std::isnan;
-  return isnan(x);
-}
+#import <iostream>
+// Let's be conservative and enable the std::isnan implementation only if we are sure it exists
+#if (__cplusplus >= 201103L) && (EIGEN_COMP_GNUC_STRICT || EIGEN_COMP_CLANG || EIGEN_COMP_MSVC || EIGEN_COMP_ICC)  \
+&& (EIGEN_ARCH_i386_OR_x86_64) && (EIGEN_OS_GNULINUX || EIGEN_OS_WIN_STRICT || EIGEN_OS_MAC) \
+|| defined(EIGEN_HAS_C99_MATH)
+  template<typename T>
+  EIGEN_DEVICE_FUNC
+  bool (isNaN)(const T& x)
+  {
+    using std::isnan;
+    return isnan(x);
+  }
+#else
+  template<typename T>
+  EIGEN_DEVICE_FUNC
+  bool (isNaN)(const T& x)
+  {
+      return x == x;
+  }
+#endif
 
 template<typename T>
 EIGEN_DEVICE_FUNC
@@ -809,13 +821,25 @@ bool (isNaN)(const std::complex<T>& x)
   return isnan(real(x)) || isnan(imag(x));
 }
 
-template<typename T>
-EIGEN_DEVICE_FUNC
-bool (isInf)(const T& x)
-{
-  using std::isinf;
-  return isinf(x);
-}
+// Let's be conservative and enable the std::isinf implementation only if we are sure it exists
+#if (__cplusplus >= 201103L) && (EIGEN_COMP_GNUC_STRICT || EIGEN_COMP_CLANG || EIGEN_COMP_MSVC || EIGEN_COMP_ICC)  \
+&& (EIGEN_ARCH_i386_OR_x86_64) && (EIGEN_OS_GNULINUX || EIGEN_OS_WIN_STRICT || EIGEN_OS_MAC) \
+|| defined(EIGEN_HAS_C99_MATH)
+  template<typename T>
+  EIGEN_DEVICE_FUNC
+  bool (isInf)(const T& x)
+  {
+    using std::isinf;
+    return isinf(x);
+  }
+#else
+  template<typename T>
+  EIGEN_DEVICE_FUNC
+  bool (isInf)(const T& x)
+  {
+    return x>NumTraits<T>::highest() || x<NumTraits<T>::lowest();
+  }
+#endif
 
 template<typename T>
 EIGEN_DEVICE_FUNC
diff --git a/Eigen/src/Core/util/Macros.h b/Eigen/src/Core/util/Macros.h
index aaea9f035..754e2c7cc 100644
--- a/Eigen/src/Core/util/Macros.h
+++ b/Eigen/src/Core/util/Macros.h
@@ -398,6 +398,14 @@
 #define EIGEN_HAS_CONSTEXPR 1
 #endif
 
+// Does the compiler support C99 math?
+#if (EIGEN_COMP_GNUC_STRICT || \
+  (EIGEN_COMP_ICC && EIGEN_COMP_GNUC) || \
+  (EIGEN_COMP_CLANG) || \
+  (EIGEN_COMP_MSVC >= 1800))
+#define EIGEN_HAS_C99_MATH 1
+#endif
+
 /** Allows to disable some optimizations which might affect the accuracy of the result.
   * Such optimization are enabled by default, and set EIGEN_FAST_MATH to 0 to disable them.
   * They currently include:
-- 
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