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Re: Exception handling + Optimisation
- To: Andi Kleen <ak at muc dot de>
- Subject: Re: Exception handling + Optimisation
- From: Jeffrey A Law <law at cygnus dot com>
- Date: Wed, 10 Jun 1998 10:26:41 -0600
- cc: Alexandre Oliva <oliva at dcc dot unicamp dot br>, dg at cogency dot co dot uk (David Gilbert), egcs at cygnus dot com
- Reply-To: law at cygnus dot com
In message <k2soldj1x9.fsf@zero.aec.at>you write:
> > That was the case in gcc 2.7.* only; EH with optimization is suported
> > in 2.8.* and egcs.
>
> It seems to turn off some optimizations though - e.g. I find this
> in the haifa scheduler/is_cfg_nonregular:
[ ... ]
Yes. That code pre-dates accurate flow graphs. It would be interesting
for someone to take out that code and see if their EH still works
with optimization :-)
If it doesn't, that would indicate that we've still got problems in
the cfg.
Note that EH is (in general) going to reduce the effectiveness of
many optimizations. Basically certain transformations the compiler
used to make are not safe with EH code.
jeff