Allow conditionals choosing between tensors

The indexing information needs to be stored and reset
for visiting of the second branch.

python/dune/perftool/ufl/visitor.py

@@ -325,7 +325,15 @@ class UFL2LoopyVisitor(ModifiedTerminalTracker):
     #
 
     def conditional(self, o):
-        return prim.If(*tuple(self.call(op) for op in o.ufl_operands))
+        condition = self.call(o.ufl_operands[0])
+        indices = self.indices
+
+        op1 = self.call(o.ufl_operands[1])
+        # Restore indexing information for the second branch
+        self.indices = indices
+        op2 = self.call(o.ufl_operands[2])
+
+        return prim.If(condition, op1, op2)
 
     def eq(self, o):
         return prim.Comparison(self.call(o.ufl_operands[0]),