Try with
ContourPlot[Evaluate[cir1], {x, -1, 1}, {y, -1, 1}]
ContourPlot (and Plot and most plotting functions) protects its argument from outside assignements of variables. Without this protection the following would not work:
x=1; Plot[ x^2, {x,0,1}]
because it would give Plot[1^2, {x,0,1}].
This (mostly) benign protection can be bypassed with Evaluate, when necessary and with care.
