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GUFA miscompilation with shared i31 cast #6776
Description
(module
(table $0 3 3 (ref null (shared any)))
(elem $0 (table $0) (i32.const 0) (ref null (shared i31)) (item (ref.i31_shared (i32.const 999))))
(func $0 (export "get") (param $0 i32) (result (ref null (shared any)))
(ref.cast (ref null (shared i31))
(table.get $0
(i32.const 0)
)
)
)
)
Running wasm-opt -all -tnh --gufa-cast-all test.wast -S -o - optimizes the function body to just (ref.null (shared none)), which is not correct. I tried debugging this and I figured out that there is an intermediate state where the ref.cast type has been changed to (ref null (shared none)), but I haven't been able to figure out why it's doing that.
Activity
kripken commentedon Jul 19, 2024
As a quick guess, perhaps one of the first four methods here (
combine, intersect, haveIntersection, isSubContents) need updating for shared types? Might be easiest to verify if that is the case by adding some cases to the existing test.[threads] Calculate shared heap type depths in subtypes.h
[threads] Calculate shared heap type depths in subtypes.h (#6777)