[LLVMdev] [llvmdev] Whole function SelectionDAG

Dan Gohman gohman at apple.com
Fri Jun 11 09:28:53 PDT 2010



On Jun 8, 2010, at 8:33 PM, Zhongxing Xu <xuzhongxing at gmail.com> wrote:

> At first I'll try the simplest strategy: put the instruction in the  
> machine BB corresponding to the LLVM BB where it comes from.
>
> To implement this, I plan to add an operand to non-passive node  
> which points to the BasicBlockSDNode which the node belongs to.

This would inhibit cross-block CSE, which would be one of the main  
benefits of whole-function processing.  What problem are you trying to  
solve?

>
>
> Another idea is to use a side map to map each node to its block. But  
> I guess it's difficult to keep the map consistent when transforming  
> the DAG.

Yep.

Dan



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