perf(rust, python): add optimizer passes and change initial order #8811
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ritchie46
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May 12, 2023
| { | ||
| let expr = unsafe { expr_arena.get_unchecked(current_expr_node) }; | ||
| // don't apply rules to `col`, `lit` etc. | ||
| if expr.is_leaf() { |
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This will be most expressions and it is pointless to optimize them as they are atomic.
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The stack optimizer passes expression from root to leafs.
That means that this expression:
lit(1) * lit(2) + col("a")would be exposed to the optimizer in this order:
lit(1) * lit(2) + col("a")lit(1) * lit(2)lit(1)lit(2)col("a")And that fused multiply add optimization already triggers on 1 before constant folding can be triggered on 2.
So this PR changes the initial traversal of the expressions so that the stack will first traversed in order
5, 4, .. 1, meaning that smaller argument optimizations can be triggered first.This will increase the amount of passes we take, but hopefully the extra triggered optimizations will be worth it.