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Cranelift: ISLE: Clif type args should always be controlling type - #15052
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Per discussion with cfallin, when a Clif ISLE term has a type (e.g. `(icmp ty x y)`, the type should be the controlling type from the Clif definition (here, the width of `x`/`y`), not the result type (here, `i8`) when they differ. Make this change and update the affected rules. Note this actually improves GVN due to it previously failing to deduplicate across the version of the instruction that correctly used the controlling type (before the egraph) and the one using the result type (in the egraph).
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This looks correct to me, after going over the rule edits -- thanks for the careful work!
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Per discussion with @cfallin, when a Clif ISLE term has a type parameter, the type should always be the controlling type from the Clif definition (e.g., the width of
x/yin(icmp ty x y)), not the result type (e.g.,i8) when they differ. Make this change and update the affected rules (257 of them) and ISLE specs. This requires introducing ahas_typehelper intooptfor cases where rules do intend to match on the result type.Note this had the nice consequence of improving GVN due to it previously failing to deduplicate across the version of the instruction that correctly used the controlling type (before the egraph) and the one using the result type (in the egraph). I have not yet tried to measure if this has any performance impact. This PR also fixes more cases where opt rules were only firing at
i8due to the conflation of the two types (related to #14964).