[PATCH 2/n] [PR tree-optimization/78496] Simplify ASSERT_EXPRs to facilitate jump threading

[Jeff Law]

On 05/08/2017 09:54 AM, Jeff Law wrote:
> So I'm not sure if changing VRP with your patches is a good thing when 
>> you
>> could have used the new API in the first place ...
> I don't see that the changes to date around 78496 change things 
> significantly in regards to the immediate plans to remove ASSERT_EXPR. 
> The work around 78496 raises the bar in terms of what information we 
> need to be able to extract, but that IMHO, is a fine thing to do ;-)
As expected, it's pretty easy to change to the newer way of doing 
things.  ie, extracting from the GIMPLE_COND rather than the 
ASSERT_EXPR.   It really isn't a big deal.


> 
> 
> However, the existence of register_edge_assert_for does change how I'm 
> looking at the next issue for 78496 as well as how to tackle a host of 
> related issues.  It may end up being the case that we stop 78496 work 
> after patch #2, work on ASSERT_EXPR removal, then re-eval 78496.
And as expected the unwindable VRs do help significantly in the 3rd hunk 
of the work for 78496.  Probably the biggest issue here is how to 
compose the bits to avoid code duplication between EVRP and the VRP jump 
threading.

Jeff