[PATCH] D146267: [llvm] Handle duplicate call bases when applying branch funneling

Tue Mar 21 17:07:06 PDT 2023

leonardchan marked an inline comment as not done.
leonardchan added inline comments.

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Comment at: llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp:1397

+      if (!CB.getParent()) {
+        // When finding devirtualizable calls, it's possible to find the same
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aeubanks wrote:
> leonardchan wrote:
> > tejohnson wrote:
> > > I don't think this is safe since when we eraseFromParent the instruction is deleted. Can we track a different way?
> > Updated to just add erased pointers to a set and check on future iterations if they're in the set. This way we don't have to deref them.
> if the instruction is erased, can there be instructions created after that share the same pointer?
Hmm, I would think yes, but I think for this specific case it doesn't matter since none of the newly created instructions in this loop get added back to `CSInfo.CallSites` so each of the CBs should only refer to CBs that were added earlier.

Repository:
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  https://reviews.llvm.org/D146267/new/

https://reviews.llvm.org/D146267