[LLVMdev] Exception Handling Proposal, Second round Re: LLVMdev Digest, Vol 83, Issue 30

[Andrew Trick]

On May 18, 2011, at 8:35 AM, Peter Lawrence wrote:

> Renato,
>                I agree with what Andrew said, but would have worded it differently. All optimizers (that
> I am aware of) require explicit control flow, so things like exception-throwing-divide-instructions
> need to be converted into IR that are Block-Terminators.  Andrew was explaining how this is
> a non-performance issue in practice, I am explaining how this is a requirement of how optimizer
> are implemented in practice.
> 
> -Peter Lawrence.

Thanks for the clarification, Peter. I was trying to convey two main points: 
1) Optimizers require explicit control flow, which is not a limitation because it's easy to optimize across branches (calls and merges are hard to handle).
2) Codegen can convert control flow to trapping instructions, but it's seldom worthwhile.

-Andy

> On May 18, 2011, at 1:34 AM, llvmdev-request at cs.uiuc.edu wrote:
> 
>> On 18 May 2011 03:10, Andrew Trick <atrick at apple.com> wrote:
>>> This sounds like something that came out of a brainstorming session then snuck into the project requirements when it's really a separate issue. I think you can safely ignore it.
>> 
>> Ah, great! It was something someone asked about and I've only heard
>> "don't worry about it" but never heard a full explanation, until now!
>> ;)
>> 
>> Thanks!
>> --renato
> 
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