diff --git a/Eigen/src/Core/products/GeneralBlockPanelKernel.h b/Eigen/src/Core/products/GeneralBlockPanelKernel.h
index d2e6f26c8..54e118395 100644
--- a/Eigen/src/Core/products/GeneralBlockPanelKernel.h
+++ b/Eigen/src/Core/products/GeneralBlockPanelKernel.h
@@ -178,7 +178,7 @@ void evaluateProductBlockingSizesHeuristic(Index& k, Index& m, Index& n, Index n
     // We also include a register-level block of the result (mx x nr).
     // (In an ideal world only the lhs panel would stay in L1)
     // Moreover, kc has to be a multiple of 8 to be compatible with loop peeling, leading to a maximum blocking size of:
-    const Index max_kc = ((l1-k_sub)/k_div) & (~(k_peeling-1));
+    const Index max_kc = std::max<Index>(((l1-k_sub)/k_div) & (~(k_peeling-1)),1);
     const Index old_k = k;
     if(k>max_kc)
     {