[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
problem.
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.
-Dave
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