230e2135d6
* Cranelift: remove non-egraphs optimization pipeline and `use_egraphs` option. This PR removes the LICM, GVN, and preopt passes, and associated support pieces, from `cranelift-codegen`. Not to worry, we still have optimizations: the egraph framework subsumes all of these, and has been on by default since #5181. A few decision points: - Filetests for the legacy LICM, GVN and simple_preopt were removed too. As we built optimizations in the egraph framework we wrote new tests for the equivalent functionality, and many of the old tests were testing specific behaviors in the old implementations that may not be relevant anymore. However if folks prefer I could take a different approach here and try to port over all of the tests. - The corresponding filetest modes (commands) were deleted too. The `test alias_analysis` mode remains, but no longer invokes a separate GVN first (since there is no separate GVN that will not also do alias analysis) so the tests were tweaked slightly to work with that. The egrpah testsuite also covers alias analysis. - The `divconst_magic_numbers` module is removed since it's unused without `simple_preopt`, though this is the one remaining optimization we still need to build in the egraphs framework, pending #5908. The magic numbers will live forever in git history so removing this in the meantime is not a major issue IMHO. - The `use_egraphs` setting itself was removed at both the Cranelift and Wasmtime levels. It has been marked deprecated for a few releases now (Wasmtime 6.0, 7.0, upcoming 8.0, and corresponding Cranelift versions) so I think this is probably OK. As an alternative if anyone feels strongly, we could leave the setting and make it a no-op. * Update test outputs for remaining test differences.
filetests
Filetests is a crate that contains multiple test suites for testing
various parts of cranelift. Each folder under cranelift/filetests/filetests is a different
test suite that tests different parts.
Adding a runtest
One of the available testsuites is the "runtest" testsuite. Its goal is to compile some piece of clif code, run it and ensure that what comes out is what we expect.
To build a run test you can add the following to a file:
test interpret
test run
target x86_64
target aarch64
target s390x
function %band_f32(f32, f32) -> f32 {
block0(v0: f32, v1: f32):
v2 = band v0, v1
return v2
}
; run: %band_f32(0x0.5, 0x1.0) == 0x1.5
Since this is a run test for band we can put it in: runtests/band.clif.
Once we have the file in the test suite we can run it by invoking: cargo run -- test filetests/filetests/runtests/band.clif from the cranelift directory.
The first lines tell clif-util what kind of tests we want to run on this file.
test interpret invokes the interpreter and checks if the conditions in the ; run comments pass. test run does the same, but compiles the file and runs it as a native binary.
For more information about testing see testing.md.