[LLVMdev] PassManager Mysteries

David A. Greene greened at obbligato.org
Mon Jan 28 19:55:36 PST 2008

On Monday 28 January 2008 09:31:11 pm Owen Anderson wrote:
>  From experience, an important point that is often forgotten is that
> the order of declaration of dependencies matter.  If you declare that
> you require pass A, and then pass B, and B doesn't preserve A, you'll
> get an error like this.
> Just some advice from having had similar problems in the past.

I'll have to double-check my code, but I don't think I have this particular

But in any case, isn't the whole point of PassManager that it can handle
situations like this?  Why wouldn't it just run Pass A twice, or run it
in the correct order (after Pass B)?

This strikes me as rather fragile.  And my experience has been that 
that is in fact exactly the case.


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