[PATCH] D29917: WholeProgramDevirt: Implement export/import support for unique ret val opt.

[Teresa Johnson via Phabricator via llvm-commits]

tejohnson accepted this revision.
tejohnson added a comment.
This revision is now accepted and ready to land.

LGTM



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Comment at: llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp:794
+    if (CSInfo.isExported()) {
+      Res->TheKind = WholeProgramDevirtResolution::ByArg::UniqueRetVal;
+      Res->Info = IsOne;
----------------
pcc wrote:
> tejohnson wrote:
> > I was trying to prove to myself that Res != nullptr when isExported(), but I am having trouble doing so. isExported() will be true when the CSInfo has SummaryTypeCheckedLoadUsers or SummaryHasTypeTestAssumeUsers - these are set up when (Action == PassSummaryAction::Export). But Res will only be non-null when (Action == PassSummaryAction::Export && isa<MDString>(S.first.TypeID)).
> > 
> > Is there a case where we could reach here when Action == PassSummaryAction::Export but !isa<MDString>(S.first.TypeID)? 
> I think isExported() can only possibly be true for type IDs of type MDString because we only add MDStrings to MetadataByGUID (see http://llvm-cs.pcc.me.uk/lib/Transforms/IPO/WholeProgramDevirt.cpp#1204) and we only ever set SummaryTypeCheckedLoadUsers or SummaryHasTypeTestAssumeUsers on members of MetadataByGUID.
Ok thanks, missed that.


https://reviews.llvm.org/D29917