Simon Pilgrim 70eb508605 [SelectionDAG] ComputeKnownBits - add support for SMIN+SMAX clamp patterns
If we have a clamp pattern, SMIN(SMAX(X, LO),HI) or SMAX(SMIN(X, HI),LO) then we can deduce that the number of signbits (zeros/ones) will be at least the minimum of the LO and HI constants.

ComputeKnownBits equivalent of D43338.

Differential Revision: https://reviews.llvm.org/D43463

llvm-svn: 325521
2018-02-19 18:08:16 +00:00
..
2017-10-24 17:23:40 +00:00