[PATCH] D133637: Bug fix on stable hash calculation for machine operands RegisterMask and RegisterLiveOut

[YongKang Zhu via Phabricator via llvm-commits]

yozhu added a comment.

In D133637#3782281 <https://reviews.llvm.org/D133637#3782281>, @smeenai wrote:

> Is it possible to add a test case to prevent this from regressing in the future? (It;s fine if the answer is "no"; I'm not familiar enough with this part of the code to say.)

I'm not sure if it is feasible to add a small unit test for this. Stable hash calculated on machine operand doesn't exist in compiler output or produced OBJ or binary, and also it is hard to tell whether a hash value is calculated from hashing pointers or raw data. The problem was manifested as non-determinism in binary. If we test determinism, then the input need to be relatively large (larger than usual unit test) so any inherent randomness could be exposed relatively reliably. But determinism test will verify the whole toolset instead of only testing machine IR stable hash calculation.


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https://reviews.llvm.org/D133637