what optimizations are invalid in java?

Sun Mar 10 04:21:00 GMT 2002

Hi,
thinking more about Java and exceptions, can someone who understand
standard better than I do comment what transfromations are valid and
what invalid:
fold_const: We can remove dead parts of expresisons poossibly eliminating
 trap.
delete_trivially_dead_instruction: We remove dead trapping code here
cleanup_cfg: We may eliminate fp comparison that traps in case the associated
 branch is not needed.
CSE: I guess we are safe here. We are only eliminating code that would
 happend previously.
GCSE: Can we do code motion that reorder traps? I guess not.
loop: Should be safe
Combine: We may elliminate traps here by smplifying expressions and for instance
 discovering that given memory operand does not affect the result.
Honza