[PATCH] D98659: [MachineCopyPropagation] Do more backward copy propagations

[yshui via Phabricator via llvm-commits]

yshui added a comment.

In D98659#2648161 <https://reviews.llvm.org/D98659#2648161>, @jmorse wrote:

> There isn't a lot of difference to how debug-info is updated, as far as I can see, but the summary says a fault is resolved. Is this patch just masking the debug-info issue by doing more propagation? (I might have missed something in the implementation).

I am not exactly sure what you mean here. The fault is caused by debug-info preventing propagation from happening, this patch fixes that problem.

> For the codegen change -- I would suggest this additional feature deserves a dedicated MIR test. All the tests modified are IR-to-assembly, where unrelated changes to other parts of the compiler might obscure this feature being accidentally disabled or otherwise modified. A MIR test for this specific behaviour in this specific pass will guarantee it isn't broken in the future. Plus, it'll make it easier for reviewers and post-review-readers to understand the patch.

I agree, but I mentioned above I have problem creating an small IR input that would generate the kind of MIR pattern I need. There is a test case attached to the issue but it's quite big.


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https://reviews.llvm.org/D98659