[PATCH] D18069: Throttling LICM to reduce compile time of Value Propagation and Reg Splitting

[Philip Reames via llvm-commits]

David,

I very deeply believe that limiting hoisting in the IR to reduce 
register pressure is fundamentally the wrong approach.  The backend is 
responsible for sinking if desired to reduce register pressure. We do 
not model register pressure in the IR.  At all.  Period.

Philip

On 03/11/2016 05:08 PM, David Li wrote:
> davidxl added a comment.
>
> I have not read the patch in details, but it seems the main purpose of the patch to throttle LICM to reduce register pressure and the compile time benefit due to reduced LVI queries is just a good side effect of the patch? Do we have any performance data (runtime) showing the usefulness of the throttling?  (Whether this is the right approach to solve the spill problem is also subject to discussions).
>
>
> Repository:
>    rL LLVM
>
> http://reviews.llvm.org/D18069
>
>
>