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Re: [RFC] Adjusted VRP


On Thu, Oct 30, 2014 at 04:19:24PM +0300, Marat Zakirov wrote:
> We didn't find reasonable performance gains to use VRP in asan. But even if
> we found we couldn't use it because it is not safe for asan. It make some
> optimistic conclusions invalid for asan.
> 
> Adjusted VRP memory upper bound is #{trees that are compared} x nblocks
> which could be reduced by some threshold.
> 
> If making stuff inside VRP is a right thing why can't we do all
> VRP-dependent optimizations in the VRP transform phase? Why do we need
> range_infos if they are so imprecise?!

It is not imprecise, and really isn't (so far) used that heavily in the
compiler, most of the optimizations based on value ranges really do happen
in the VRP tansform phase.

	Jakub


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