diff --git a/expr.cpp b/expr.cpp
index cacbb312..4f516382 100644
--- a/expr.cpp
+++ b/expr.cpp
@@ -2314,6 +2314,7 @@ BinaryExpr::TypeCheck() {
         if (type1->IsVaryingType()) {
             arg0 = TypeConvertExpr(arg0, type0->GetAsVaryingType(), 
                                    "pointer addition");
+            offsetType = offsetType->GetAsVaryingType();
             Assert(arg0 != NULL);
         }
 
diff --git a/tests/ptr-math-variability.ispc b/tests/ptr-math-variability.ispc
new file mode 100644
index 00000000..4fa89206
--- /dev/null
+++ b/tests/ptr-math-variability.ispc
@@ -0,0 +1,12 @@
+
+export uniform int width() { return programCount; }
+
+
+export void f_f(uniform float RET[], uniform float aFOO[]) {
+    uniform float * uniform ptr = aFOO;
+    RET[programIndex] = *(ptr + programIndex) - 1;
+}
+
+export void result(uniform float RET[]) {
+    RET[programIndex] = programIndex;
+}