[PATCH] D45315: [X86] Improve unsigned saturation downconvert detection.

[Artur Gainullin via Phabricator via llvm-commits]

ArturGainullin added a comment.

(truncate (smin (smax (x, C1), C2)) to dest_type)
is equivalent to 
 (truncate (umin (smax(x, C1), unsigned_max_of_dest_type)) to dest_type)
that is why I don't need to create any node and just return smax.

But in case of 
 (truncate (smax (smin (x, C2), C1)) to dest_type)
which is also equivalent to 
 (truncate (umin (smax(x, C1), unsigned_max_of_dest_type)) to dest_type)
I need to create new smax node and return it.


Repository:
  rL LLVM

https://reviews.llvm.org/D45315