diff --git a/gem/flop_count.py b/gem/flop_count.py
index 934c3386..b9595e81 100644
--- a/gem/flop_count.py
+++ b/gem/flop_count.py
@@ -142,7 +142,7 @@ def flops_indexed(expr, temporaries):
     aggregate = sum(expression_flops(child, temporaries)
                     for child in expr.children)
     # Average flops per entry
-    return aggregate / numpy.product(expr.children[0].shape, dtype=int)
+    return aggregate / numpy.prod(expr.children[0].shape, dtype=int)
 
 
 @flops.register(gem.IndexSum)
diff --git a/tsfc/loopy.py b/tsfc/loopy.py
index be668d57..e90899d8 100644
--- a/tsfc/loopy.py
+++ b/tsfc/loopy.py
@@ -109,7 +109,7 @@ def assign_dtypes(expressions, scalar_type):
     mapper = Memoizer(_assign_dtype)
     mapper.scalar_type = scalar_type
     mapper.real_type = numpy.finfo(scalar_type).dtype
-    return [(e, numpy.find_common_type(mapper(e), [])) for e in expressions]
+    return [(e, numpy.result_type(*mapper(e))) for e in expressions]
 
 
 class LoopyContext(object):