tree-ssa: a weird (mis)optimization

[Richard Henderson]

On Wed, Dec 01, 2004 at 10:13:45AM +0000, Andrew Haley wrote:
> Let me put it this way: a trapping instruction has an abnormal edge in
> the CFG, so why would it get deleted?

Well, for one, I didn't think things worked this way.  It doesn't
make a whole lot of sense to me.  We work hard to *get rid* of 
instructions that trap, and to remove the associated abnormal edges.

I still think that the Java front end should be doing something in
order to indicate that these loads should not be removed, beyond
just marking them as trapping -- or rather, not marking them as not
trapping.  Otherwise -fnon-call-exceptions will suddenly generate
*significantly* worse code for everyone else.



r~