From 52d1dd979af688fbf67c34860527b3a4295b7936 Mon Sep 17 00:00:00 2001
From: Antonio Sanchez <cantonios@google.com>
Date: Wed, 6 Jan 2021 13:14:20 -0800
Subject: [PATCH] Fix Ref initialization.

Since `eigen_assert` is a macro, the statements can become noops (e.g.
when compiling for GPU), so they may not execute the contained logic -- which
in this case is the entire `Ref` construction.  We need to separate the assert
from statements which have consequences.

Fixes #2113
---
 Eigen/src/Core/Ref.h | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/Eigen/src/Core/Ref.h b/Eigen/src/Core/Ref.h
index 00aa45d34..9fca42873 100644
--- a/Eigen/src/Core/Ref.h
+++ b/Eigen/src/Core/Ref.h
@@ -94,7 +94,7 @@ protected:
   typedef Stride<StrideType::OuterStrideAtCompileTime,StrideType::InnerStrideAtCompileTime> StrideBase;
 
   // Resolves inner stride if default 0.
-  static Index resolveInnerStride(Index inner) {
+  static EIGEN_DEVICE_FUNC Index resolveInnerStride(Index inner) {
     if (inner == 0) {
       return 1;
     }
@@ -102,7 +102,7 @@ protected:
   }
   
   // Resolves outer stride if default 0.
-  static Index resolveOuterStride(Index inner, Index outer, Index rows, Index cols, bool isVectorAtCompileTime, bool isRowMajor) {
+  static EIGEN_DEVICE_FUNC Index resolveOuterStride(Index inner, Index outer, Index rows, Index cols, bool isVectorAtCompileTime, bool isRowMajor) {
     if (outer == 0) {
       if (isVectorAtCompileTime) {
         outer = inner * rows * cols;
@@ -311,7 +311,9 @@ template<typename PlainObjectType, int Options, typename StrideType> class Ref
     {
       EIGEN_STATIC_ASSERT(bool(Traits::template match<Derived>::MatchAtCompileTime), STORAGE_LAYOUT_DOES_NOT_MATCH);
       // Construction must pass since we will not create temprary storage in the non-const case.
-      eigen_assert(Base::construct(expr.derived()));
+      const bool success = Base::construct(expr.derived());
+      EIGEN_UNUSED_VARIABLE(success)
+      eigen_assert(success);
     }
     template<typename Derived>
     EIGEN_DEVICE_FUNC inline Ref(const DenseBase<Derived>& expr,
@@ -326,7 +328,9 @@ template<typename PlainObjectType, int Options, typename StrideType> class Ref
       EIGEN_STATIC_ASSERT(bool(Traits::template match<Derived>::MatchAtCompileTime), STORAGE_LAYOUT_DOES_NOT_MATCH);
       EIGEN_STATIC_ASSERT(!Derived::IsPlainObjectBase,THIS_EXPRESSION_IS_NOT_A_LVALUE__IT_IS_READ_ONLY);
       // Construction must pass since we will not create temporary storage in the non-const case.
-      eigen_assert(Base::construct(expr.const_cast_derived()));
+      const bool success = Base::construct(expr.const_cast_derived());
+      EIGEN_UNUSED_VARIABLE(success)
+      eigen_assert(success);
     }
 
     EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Ref)