[LLVMdev] Bug 1868: Specifying Pass Orderings

Devang Patel dpatel at apple.com
Mon Dec 17 14:36:51 PST 2007

On Dec 17, 2007, at 2:25 PM, John Criswell wrote:

> So, is there a way for a Pass to specify that other transforms  
> should be
> run first, or can that only be done with PassManager.add()?

PassManager.add() is the way to go.

If one relies on PassManager to order transformations passes properly  
then we are stepping into "Find optimal ordering of optimization/ 
transformations passes sequence to generate the best code for my  
application" area. I'd prefer to stay out of that, because it is non- 
trivial. Instead, let PassManager users (e.g. llvm-gcc, opt. SAFECode  
driver?) decide the ordering of transformations.


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