[PATCH] D29107: Fix a bug when unswitching on partial LIV for SwitchInst

[Xin Tong via Phabricator via llvm-commits]

trentxintong added a comment.

Basically, there are 2 problems here this patch addresses.

1. we try to find a value that actually simplify the operator chain and in case we cant, we give up and this is better than picking a random value and hope it simplifies.
2. we fix how unswitch value is recorded. current way (before the patch) can not record partial LIV.

Both are needed to have the patch working, as we can not allow partial LIV by walking up the chain and not fixing how to record unswitched partial LIV correctly.


https://reviews.llvm.org/D29107