Free element (but not its leaves! (assume they are already freed)) Don't decrement Ecount! This is so we can detect if the common subexp has already been evaluated. If common subexpression is not required anymore, eliminate references to it.
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Free element (but not its leaves! (assume they are already freed)) Don't decrement Ecount! This is so we can detect if the common subexp has already been evaluated. If common subexpression is not required anymore, eliminate references to it.