[PATCH] D38916: [GlobalDCE] Use DenseMap instead of unordered_multimap for GVDependencies.

[Michael Zolotukhin via Phabricator via llvm-commits]

mzolotukhin added a comment.

> Generally switching to generic containers to LLVM ones lead to improvements, but 17x seems quite large to me (not complaining).

17x probably comes from the test being huge: when we're building with LTO, we're getting a ~50Mb bitcode file.

> I wonder if you can add a test (maybe to CTMark?) to make sure this doesn't regress.

I thought about that too. But I thought maybe we should create a compile time regression test-suite instead, which will be separate from CTMark. That is, I definitely agree that it'd be great to be able to check if tests don't regress, but I would also like to keep CTMark runs fast. It's discussable though.
Another problem with this particular test is that I cannot disclose it as is, but I guess if we just generate a huge file with tons of globals and functions that would also do.

Michael


https://reviews.llvm.org/D38916