From fd4e366d7e224364a24d278bc23a0dca5d7472ce Mon Sep 17 00:00:00 2001
From: Benoit Jacob <jacob.benoit.1@gmail.com>
Date: Sun, 2 Jan 2011 12:07:39 -0500
Subject: [PATCH] fix severe perf bug: coeff-based matrix products were not
 considered aligned, typically preventing vectorization. added unit test.

---
 Eigen/src/Core/products/CoeffBasedProduct.h | 1 +
 test/vectorization_logic.cpp                | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/Eigen/src/Core/products/CoeffBasedProduct.h b/Eigen/src/Core/products/CoeffBasedProduct.h
index 8605011da..878956a33 100644
--- a/Eigen/src/Core/products/CoeffBasedProduct.h
+++ b/Eigen/src/Core/products/CoeffBasedProduct.h
@@ -98,6 +98,7 @@ struct traits<CoeffBasedProduct<LhsNested,RhsNested,NestingFlags> >
       Flags = ((unsigned int)(LhsFlags | RhsFlags) & HereditaryBits & ~RowMajorBit)
             | (EvalToRowMajor ? RowMajorBit : 0)
             | NestingFlags
+            | (LhsFlags & RhsFlags & AlignedBit)
             // TODO enable vectorization for mixed types
             | (SameType && (CanVectorizeLhs || CanVectorizeRhs) ? PacketAccessBit : 0),
 
diff --git a/test/vectorization_logic.cpp b/test/vectorization_logic.cpp
index 1a00af840..911b79d0d 100644
--- a/test/vectorization_logic.cpp
+++ b/test/vectorization_logic.cpp
@@ -186,6 +186,8 @@ template<typename Scalar, bool Enable = internal::packet_traits<Scalar>::Vectori
             Matrix22
             >(DefaultTraversal,CompleteUnrolling)));
 
+    VERIFY((test_assign(Matrix11(), Matrix11()*Matrix11(), InnerVectorizedTraversal, CompleteUnrolling)));
+
     VERIFY(test_redux(VectorX(10),
       LinearVectorizedTraversal,NoUnrolling));