commit 2c4541f735d3dad2ce312bf785c366668d646f3b
author Charles Schlosser <cs.schlosser@gmail.com> Wed Dec 13 03:33:49 2023 +0000
committer Charles Schlosser <cs.schlosser@gmail.com> Wed Dec 13 03:33:49 2023 +0000
tree 7a59fe59dc57571caf5a79d3d1730a5951eba463
parent 75e273afcc86c4580aae12fb4e6e68c252cc2af0

fix msvc clz

Eigen/src/Core/MathFunctions.h

diff --git a/Eigen/src/Core/MathFunctions.h b/Eigen/src/Core/MathFunctions.h
index 087d5db..0be29bc 100644
--- a/Eigen/src/Core/MathFunctions.h
+++ b/Eigen/src/Core/MathFunctions.h
@@ -733,10 +733,9 @@
   static constexpr int kNumBits = static_cast<int>(sizeof(BitsType) * CHAR_BIT);
   static_assert(std::is_integral<BitsType>::value, "BitsType must be a built-in integer");
   static EIGEN_DEVICE_FUNC inline int clz(BitsType bits) {
-    static constexpr int kLeadingBitsOffset = static_cast<int>((sizeof(unsigned long) - sizeof(BitsType)) * CHAR_BIT);
     unsigned long out;
     _BitScanReverse(&out, static_cast<unsigned long>(bits));
-    return bits == 0 ? kNumBits : static_cast<int>(out - kLeadingBitsOffset);
+    return bits == 0 ? kNumBits : (kNumBits - 1) - static_cast<int>(out);
   }
 
   static EIGEN_DEVICE_FUNC inline int ctz(BitsType bits) {
@@ -754,10 +753,9 @@
   static constexpr int kNumBits = static_cast<int>(sizeof(BitsType) * CHAR_BIT);
   static_assert(std::is_integral<BitsType>::value, "BitsType must be a built-in integer");
   static EIGEN_DEVICE_FUNC inline int clz(BitsType bits) {
-    static constexpr int kLeadingBitsOffset = static_cast<int>((sizeof(__int64) - sizeof(BitsType)) * CHAR_BIT);
     unsigned long out;
     _BitScanReverse64(&out, static_cast<unsigned __int64>(bits));
-    return bits == 0 ? kNumBits : static_cast<int>(out - kLeadingBitsOffset);
+    return bits == 0 ? kNumBits : (kNumBits - 1) - static_cast<int>(out);
   }
 
   static EIGEN_DEVICE_FUNC inline int ctz(BitsType bits) {