diff --git a/loopy/kernel/data.py b/loopy/kernel/data.py
index 832096a32594e03c5263f2b143715e9c5a022aa8..94ae93f3f02cd0e272dceea69bd4f881711039d9 100644
--- a/loopy/kernel/data.py
+++ b/loopy/kernel/data.py
@@ -509,7 +509,10 @@ class ExpressionInstruction(InstructionBase):
     @memoize_method
     def read_dependency_names(self):
         from loopy.symbolic import get_dependencies
-        return get_dependencies(self.expression)
+        result = get_dependencies(self.expression)
+        for _, subscript in self.assignees_and_indices():
+            result = result | get_dependencies(subscript)
+        return result
 
     @memoize_method
     def reduction_inames(self):
@@ -680,6 +683,9 @@ class CInstruction(InstructionBase):
         for name, iname_expr in self.iname_exprs:
             result.update(get_dependencies(iname_expr))
 
+        for _, subscript in self.assignees_and_indices():
+            result.update(get_dependencies(subscript))
+
         return frozenset(result)
 
     def reduction_inames(self):
diff --git a/test/test_loopy.py b/test/test_loopy.py
index e1a05380d0d31acc9210578ecc72891c0dec84c0..0efcaab050d6ce0fc2b6eb95c0a52517b82f9b64 100644
--- a/test/test_loopy.py
+++ b/test/test_loopy.py
@@ -1227,6 +1227,26 @@ def test_dependent_domain_insn_iname_finding(ctx_factory):
                 ))
 
 
+def test_inames_deps_from_write_subscript(ctx_factory):
+    ctx = ctx_factory()
+
+    knl = lp.make_kernel(ctx.devices[0], [
+            "{[i,j]: 0<=i,j<n}",
+            ],
+            """
+                <> src_ibox = source_boxes[i]
+                <int32> something = 5
+                a[src_ibox] = sum(j, something) {id=myred}
+                """,
+            [
+                lp.GlobalArg("box_source_starts,box_source_counts_nonchild,a",
+                    None, shape=None),
+                "..."])
+
+    print knl
+    assert "i" in knl.insn_inames("myred")
+
+
 if __name__ == "__main__":
     if len(sys.argv) > 1:
         exec(sys.argv[1])