[PATCH] D116692: [SimplifyCFG] Tail-merging all blocks with `unreachable` terminator, final take

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a reviewer: reames.
lebedev.ri added a comment.

In D116692#3232485 <https://reviews.llvm.org/D116692#3232485>, @nikic wrote:

> It looks like the new version still has the large code size regressions (9% on mafft, 3% on 7zip). I understand that some code size increase is expected (and intended), but I don't think a particularly good case for the tradeoff has been made yet (in terms of where / how much performance this is buying for more code size). Though maybe I missed this in previous discussion threads.

How do we know that whatever compile time benchmark we see regresses is a reliable indicator in this regard?
I think this is yet another irresolvable clash between the optimization and compilation time/size.
-O3 does not mean "please quickly give me minimal code", there's -Os/-Oz for that.
IOW if you indent to block a patch, could you please actually do so, not just waguley imply so?

> I should probably test how this impacts rust code (which has a lot of unreachable terminators in release builds due to bounds checks), though that requires applying this patch on top of LLVM 13.

Were you able to to so?


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https://reviews.llvm.org/D116692