[PATCH] D78277: [SimpleLoopUnswitch] Update DefaultExit condition to check unreachable is not empty.

[Chandler Carruth via Phabricator via llvm-commits]

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

LGTM with the addition of skipping debug info as Eli suggests.



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Comment at: llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp:614
+    bool isUnreachable = isa<UnreachableInst>(TI);
+    return !isUnreachable || (isUnreachable && (&*BBToCheck.begin() != TI));
+  };
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efriedma wrote:
> Need to skip debug info
I hadn't expected that to matter as the thing we care most about here are the empty-but-unreachable blocks *created* by this same pass (and those would never have debug info).

But I suppose you're right that we still need to skip debug info because then the frontend adding it could suddenly enable (pointless) unswitching.

Ugh, but good catch.


Repository:
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  https://reviews.llvm.org/D78277/new/

https://reviews.llvm.org/D78277