TargetInstrInfo::AnalyzeBranch can modify the MBB being analyzed #3911
Description
| Bugzilla Link | 3539 |
| Version | trunk |
| OS | All |
| Reporter | LLVM Bugzilla Contributor |
Extended Description
AnalyzeBranch may delete instructions in the MBB if they are after the last unconditional branch.
This may invalidate iterators or client's data structure (e.g. liveintervals maps). The current workaround is to only allow this when the caller explicitly permits so. The only such client is branch folding.
The current fix is to not allow AnalyzeBranch to delete instructions. Instead, branch folding should perform this optimization.