[PATCH] D126650: [InstCombine] Fix const folding of switched with default case

[Nikita Popov via Phabricator via llvm-commits]

nikic added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp:1308
+    if (SI->getDefaultDest() == PN.getParent())
+      return nullptr;
     Cond = SI->getCondition();
----------------
I don't think this is sufficient. Can you please add a test where the default doesn't directly go to the phi block, but have one dummy block in between? (That is, go to a sw.19 block from both 19 and default.)

I think the right fix would be adding a `++SuccCount[SI->getDefaultDest()]`.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D126650/new/

https://reviews.llvm.org/D126650