(In reply to Vitaliy Filippov from comment #2)

> 
> Unhandled loop condition!
> UNREACHABLE executed at
> /var/home/vitali/setup/llvm-toolchain-3.5-3.5/lib/Target/R600/
> SIAnnotateControlFlow.cpp:259!
> 
> This is probably related to bugpoint replacing the branch conditions with
> constants, which makes conditional branches effectively unconditional :) and
> SIAnnotateControlFlow::handleLoopCondition also doesn't handle this case.
> 
> Looks like an easy to fix problem?

The StructurizeCFG pass can actually create branches on constants, although it
shouldn't, which I've seen several times before. I've had a partial fix for
SIAnnotateControlFlow handling branches on constants for a while, but I've been
putting off fixing it until the less noticeable StructurizeCFG problem is
fixed.