Add debug info on sporadic compiler crash.
We've been seeing some ocassional compiler crashes on what
appears to be memory corruption or array overrrun. Dump some
extra info in those cases to assist debugging.
Also, minor cleanup of select generation. First, we
(very rarely - only once in all of the boot class path) can end
up with the body of the select being dead code. The
result of the select is never used and because of that there is
no Phi node to adjust. Just skip that case - we'll be adding
proper dead code elimination in the future (dead code is quite
rare now, but will become common with planned future optimizations).
Secondly, the class of situations in which we eliminate the
suspend check on the rejoin goto is enlarged to any diamond-shaped
2 files changed