[PATCH] D29620: [JumpThreading] Thread through guards

[Sanjoy Das via Phabricator via llvm-commits]

sanjoy added inline comments.


================
Comment at: llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp:2076
+    if (Parent == Pred2->getSinglePredecessor())
+      if (BranchInst *BI = dyn_cast<BranchInst>(Parent->getTerminator()))
+        for (auto &I : *BB)
----------------
mkazantsev wrote:
> anna wrote:
> > Hi Max, I think you need to check that branch is a conditional branch. Otherwise we can fail while trying to get the condition for the branch in `ThreadGuard` at line 2091.
> You're right, I need to add this check here.
I guess this is possible when `Pred1` and `Pred2` are the same, like:


```
Parent:
  br label %pred

pred:
  switch ... 4 -> BB; 5 -> BB; ...

BB:
  ...
```


Are there other bits in this patch that are wrong in that situation?



Repository:
  rL LLVM

https://reviews.llvm.org/D29620