[TIR][Analyzer] Simplify x==x expressions for all dtypes
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Prior to this commit, there was no rule to simplify `x == x` into `True`. In some cases, despite not having an explicit rewrite rule in `RewriteSimplifier`, the `RewriteSimplifier::CanProve` function would check if `x-x` simplifies to zero, relying on the rewrite rules used for `tir::Sub`. However, the rule to rewrite `x-x` into zero was only enabled for `int32`, `int64`, and floating-point types, so relying on this behavior was inconsistent. This commit updates the rewrite rules for both `tir::EQ` and `tir::Sub` to check for simplification of `x-x` or `x==x`, regardless of the datatype. This change preserves the fast-path for index data-types, in which `int32` and `int64` expressions may be simplified without checking for side effects. For all other dtypes, the cancellation only applies when evaluating `x` has no side effects.
sunggg
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Jul 16, 2024
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sunggg
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Great catch, @Lunderberg!
LGTM, one question.
wrongtest-intellif
approved these changes
Jul 19, 2024
tqchen
approved these changes
Jul 24, 2024
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Prior to this commit, there was no rule to simplify
x == xintoTrue. In some cases, despite not having an explicit rewrite rule inRewriteSimplifier, theRewriteSimplifier::CanProvefunction would check ifx-xsimplifies to zero, relying on the rewrite rules used fortir::Sub. However, the rule to rewritex-xinto zero was only enabled forint32,int64, and floating-point types, so relying on this behavior was inconsistent.This commit updates the rewrite rules for both
tir::EQandtir::Subto check for simplification ofx-xorx==x, regardless of the datatype. This change preserves the fast-path for index data-types, in whichint32andint64expressions may be simplified without checking for side effects. For all other dtypes, the cancellation only applies when evaluatingxhas no side effects.