From 99d75235a9567865d2c070a2840d54c8a5ad0f43 Mon Sep 17 00:00:00 2001
From: Benoit Steiner <benoit.steiner.goog@gmail.com>
Date: Mon, 13 Oct 2014 17:02:09 -0700
Subject: Misc improvements and cleanups

---
 unsupported/Eigen/CXX11/src/Tensor/TensorIntDiv.h | 26 +++++++++++++----------
 1 file changed, 15 insertions(+), 11 deletions(-)

(limited to 'unsupported/Eigen/CXX11/src/Tensor/TensorIntDiv.h')

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorIntDiv.h b/unsupported/Eigen/CXX11/src/Tensor/TensorIntDiv.h
index cf97031be..2714117ab 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorIntDiv.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorIntDiv.h
@@ -31,30 +31,34 @@ namespace internal {
 template <typename T>
 struct TensorIntDivisor {
  public:
-  TensorIntDivisor() {
+   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorIntDivisor() {
     multiplier = 0;
     shift1 = 0;
     shift2 = 0;
   }
 
   // Must have 1 <= divider <= 2^31-1
-  TensorIntDivisor(const T divider) {
-    static const int N = 32;
+   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorIntDivisor(const T divider) {
+    const int N = 32;
     eigen_assert(divider > 0);
     eigen_assert(divider <= (1<<(N-1)) - 1);
 
     // fast ln2
+#ifndef __CUDA_ARCH__
     const int leading_zeros = __builtin_clz(divider);
-    const int l = N - (leading_zeros+1);
-
-    multiplier = (static_cast<uint64_t>(1) << (N+l)) / divider - (static_cast<uint64_t>(1) << N) + 1;
-    shift1 = (std::min)(1, l);
-    shift2 = (std::max)(0, l-1);
+#else
+    const int leading_zeros = __clz(divider);
+#endif
+    const int log_div = N - (leading_zeros+1);
+
+    multiplier = (static_cast<uint64_t>(1) << (N+log_div)) / divider - (static_cast<uint64_t>(1) << N) + 1;
+    shift1 = log_div > 1 ? 1 : log_div;
+    shift2 = log_div > 1 ? log_div-1 : 0;
   }
 
   // Must have 0 <= numerator <= 2^32-1
-  T divide(const T numerator) const {
-    static const int N = 32;
+   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE T divide(const T numerator) const {
+    const int N = 32;
     eigen_assert(numerator >= 0);
     eigen_assert(numerator <= (1ull<<N) - 1);
 
@@ -71,7 +75,7 @@ struct TensorIntDivisor {
 
 
 template <typename T>
-static T operator / (const T& numerator, const TensorIntDivisor<T>& divisor) {
+static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE T operator / (const T& numerator, const TensorIntDivisor<T>& divisor) {
   return divisor.divide(numerator);
 }
 
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