diff --git a/doc/guide/myelin.md b/doc/guide/myelin.md
index a75c8707..d90b84af 100644
--- a/doc/guide/myelin.md
+++ b/doc/guide/myelin.md
@@ -134,9 +134,9 @@ cell f {  // size 2336
 
 Finally, the Myelin JIT compiler converts the optimized operations into
 [assembler code](flowasm.txt) using the selected kernel generators. The code
-generated for each function depends the negotiated layout and alignment of the
-input and output tensors as well as the features support by the CPU (SSE, AVX,
-AVX2, FMA3, AVX512, etc.).
+generated for each function depends on the negotiated layout and alignment of
+the input and output tensors as well as the features support by the CPU (SSE,
+AVX, AVX2, FMA3, AVX512, etc.).
 
 ### Computing using network cell instances
 
diff --git a/sling/myelin/express.cc b/sling/myelin/express.cc
index 3ed3df5f..127aef88 100644
--- a/sling/myelin/express.cc
+++ b/sling/myelin/express.cc
@@ -870,6 +870,7 @@ bool Express::AlwaysZero(Var *x) const {
     case MOV:
       return AlwaysZero(op->args[0]);
     case ADD:
+      return AlwaysZero(op->args[0]) && AlwaysZero(op->args[1]);
     case SUB:
       return (AlwaysZero(op->args[0]) && AlwaysZero(op->args[1])) ||
              (AlwaysOne(op->args[0]) && AlwaysOne(op->args[1]));