[PATCH] D33790: [ThinLTO] Assign ValueId only once per GUID when writing combined summary

Teresa Johnson via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Thu Jun 1 17:24:00 PDT 2017


tejohnson added a comment.

In https://reviews.llvm.org/D33790#770815, @pcc wrote:

> Have you benchmarked this change? It seems that it wouldn't make a difference for the WriteIndexesThinBackend because it always passes a ModuleToSummariesForIndex map.


No and you are right it won't really help in writing distributed indexes (I can fix that in the description). I had been hanging on to this change for a couple days and forgot why I wanted it. It just cleans up something strange I noticed when examining this code - that we will repeatedly assign value numbers to summaries with the same GUID (and you end up with non-contiguous value ids, which isn't a problem, just perhaps looks strange). The change will have more impact when writing out the whole combined index, although we don't do that in any production mode with ThinLTO (distributed or otherwise).


https://reviews.llvm.org/D33790





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