Stream: git-wasmtime

Topic: wasmtime / issue #6105 Cranelift/ISLE: remove `subsume` f...

Wasmtime GitHub notifications bot (Mar 27 2023 at 17:36):

fitzgen opened issue #6105:

We only want to subsume when simplify reduces to a constant. We can automatically do this in the code that calls into ISLE by checking if the result is a constnant. Then we can remove the subsume term from ISLE, since it is a bit subtle / footgun-y.

Wasmtime GitHub notifications bot (Mar 27 2023 at 17:36):

fitzgen labeled issue #6105:

We only want to subsume when simplify reduces to a constant. We can automatically do this in the code that calls into ISLE by checking if the result is a constnant. Then we can remove the subsume term from ISLE, since it is a bit subtle / footgun-y.

Wasmtime GitHub notifications bot (Mar 27 2023 at 17:37):

github-actions[bot] commented on issue #6105:

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Wasmtime GitHub notifications bot (Apr 25 2024 at 14:33):

KGrewal1 commented on issue #6105:

Was reading through isle and came across this issue whilst seeing what the subsume keyword was for: is this still planned?

Wasmtime GitHub notifications bot (Apr 25 2024 at 15:20):

fitzgen commented on issue #6105:

I think not, since it is still a useful tool to avoid combinatorial growth in the e-graph.

For example, if we are given a very long chain of adds and our rule to rewrite (a + (b + (c + d))) => ((a + b) + (c + d)) kicks in and would otherwise start rewriting its own rewrites to effectively explore almost all of the space of different associativity trees for the long chain of adds.

Wasmtime GitHub notifications bot (Apr 25 2024 at 15:20):

fitzgen closed issue #6105:

We only want to subsume when simplify reduces to a constant. We can automatically do this in the code that calls into ISLE by checking if the result is a constnant. Then we can remove the subsume term from ISLE, since it is a bit subtle / footgun-y.

Last updated: Oct 23 2024 at 20:03 UTC