From fa8fd4b4d57323384644394c651ca106d299695f Mon Sep 17 00:00:00 2001
From: Christopher Moore <crmoore@gmail.com>
Date: Thu, 14 May 2020 22:11:19 +0000
Subject: [PATCH] Indexed view should have RowMajorBit when there is staticly a
 single row

---
 Eigen/src/Core/IndexedView.h | 4 +++-
 test/indexed_view.cpp        | 6 ++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/Eigen/src/Core/IndexedView.h b/Eigen/src/Core/IndexedView.h
index 5c2c72496a..08476251d3 100644
--- a/Eigen/src/Core/IndexedView.h
+++ b/Eigen/src/Core/IndexedView.h
@@ -171,7 +171,9 @@ struct unary_evaluator<IndexedView<ArgType, RowIndices, ColIndices>, IndexBased>
 
     FlagsLinearAccessBit = (traits<XprType>::RowsAtCompileTime == 1 || traits<XprType>::ColsAtCompileTime == 1) ? LinearAccessBit : 0,
 
-    Flags = (evaluator<ArgType>::Flags & (HereditaryBits /*| LinearAccessBit | DirectAccessBit*/)) | FlagsLinearAccessBit,
+    FlagsRowMajorBit = traits<XprType>::FlagsRowMajorBit, 
+
+    Flags = (evaluator<ArgType>::Flags & (HereditaryBits & ~RowMajorBit /*| LinearAccessBit | DirectAccessBit*/)) | FlagsLinearAccessBit | FlagsRowMajorBit,
 
     Alignment = 0
   };
diff --git a/test/indexed_view.cpp b/test/indexed_view.cpp
index 1dff972d2d..3ac6706efe 100644
--- a/test/indexed_view.cpp
+++ b/test/indexed_view.cpp
@@ -439,6 +439,12 @@ void check_indexed_view()
     VERIFY( MATCH( A(all,1)(1), "101"));
   }
 
+  //Bug IndexView with a single static row should be RowMajor:
+  {
+    // A(1, seq(0,2,1)).cwiseAbs().colwise().replicate(2).eval();
+    STATIC_CHECK(( (internal::evaluator<decltype( A(1,seq(0,2,1)) )>::Flags & RowMajorBit) == RowMajorBit ));
+  }
+
 }
 
 EIGEN_DECLARE_TEST(indexed_view)