At the very least, can check when the target isn't a basic block and thus it's a clear win. Will fix your case.
I'm dubious about the whole thing though. Seems like it may day from when branching "down" vs. "up" mattered to branch prediction.
I'm dubious about the whole thing though. Seems like it may day from when branching "down" vs. "up" mattered to branch prediction.
https://github.com/llvm/llvm-project/blob/535df472b04208d6ae...
https://reviews.llvm.org/D29856
added the comment.
If I remove the check for `OptForSize` and `PredTBB == MBB`, we can optimize OP's report, but seem to regress basic tests like llvm/test/CodeGen/X86/conditional-tailcall.ll, literally flipping the branches incorrectly IIUC.