likun666661 opened a new pull request, #39493:
URL: https://github.com/apache/arrow/pull/39493
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### Rationale for this change
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see here: https://github.com/apache/arrow/issues/39492
We can introduce a new expression, PreEvalInExpr, which helps users
proactively expand the IN expression in SQL into an OR expression.
Simultaneously, we observe that in such cases, as shown in the diagram,
performing common subexpression elimination is valuable.
In this scenario, we notice that the IN expression has a common
subexpression, which will occur n times with n conditions in the IN clause.
This would generate IR code for computing the common subexpression n times.
Although LLVM's optimization algorithms may, with some probability, actively
eliminate redundant IR code generated by the common subexpression, it still
incurs a cost in terms of LLVM optimizing IR code.
Therefore, we can proactively perform common subexpression elimination as
illustrated. We first compute the eval_expr for the IN expression. Then, we
replace all subsequent expanded OR expression eval_expr with a read_proxy_dex.
Subsequently, the llvm_generator_code will access this read_proxy_dex, which
directly utilizes the previously computed value of eval_expr.
This optimization strategy aims to reduce the redundant computation of the
common subexpression, enhancing the efficiency of the code generation process
in LLVM.
### What changes are included in this PR?
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add an preEvalInExpr for gandiva
### Are these changes tested?
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yes,it tested!
### Are there any user-facing changes?
Add a function for TreeExprBuilder . Now user can use MakePreEvalInExpr() to
codegen some sql like : select a+3 in(c-1,b*2)
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