[Arith] Updated incorrect simplification rule

[Lunderberg]

The rules that rewrite min(floordiv(x + (A-1), A) * A, max(x, A)) and min(truncdiv(x + (A-1), A) * A, max(x, A)) into max(x, A) did not have sufficiently tight bounds. The truncdiv rule required that x >= 0, while the floordiv rule had no requirement on x. In both cases, the simplification was incorrect when x==0, as it would result in a rewrite from min(0, max(0, A)) into max(0, A).

This commit updates the rules to require that x >= 0 for each of these rules.

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• cc @junrushao _{See #10317 for details}

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[tqchen]

cc @wrongtest-intellif

[wrongtest-intellif]

x >= 0

Hi :) , is it a typo for x > 0? @Lunderberg

[wrongtest-intellif]

LGTM!

Another helper view is when x % A == 0, min(ceildiv(x, A), max(x, a)) == x, thus we should exclude the case x==0 when max(x, A) != x

[Lunderberg]

Hi :) , is it a typo for x > 0? @Lunderberg

Thank you, and yes, that was a typo. The condition was updated to require x > 0.