[llvm-dev] [RFC] Compiled regression tests. (original) (raw)

David Greene via llvm-dev llvm-dev at lists.llvm.org
Wed Jul 1 11:43:07 PDT 2020

Hal Finkel via llvm-dev <llvm-dev at lists.llvm.org> writes:

I definitely agree that we should not be trying to do this kind of checking using textual metadata-node matching in FileCheck. The alternative already available is to add an analysis pass with some kind of verifier output. This output, not the raw metadata itself, can be checked by FileCheck. We also need to check the verification code, but at least that's something we can keep just in one place. For parallel annotations, we already have such a thing (we can run opt -loops -analyze; e.g., in test/Analysis/LoopInfo/annotated-parallel-complex.ll). We also do this kind of thing for the cost model (by running with -cost-model -analyze). To what extent would making more-extensive use of this technique address the use cases you're trying to address?

Analysis tests are definitely useful but I don't think they're sufficient. By their nature, analysis tests run in a "sanitized" environment. The test specifies exactly what is analyzed and no other passes are run.

From my quick glance at Michael's example test, it's checking that the inlining pass does something specific with metadata:

; Check that the access groups (llvm.access.group) are correctly merged.

I suppose one could create an "analysis" that just dumps out metadata information. Is that what you have in mind? That seems like a lot of overhead just to write a test to check metadata.

                  -David

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