[PATCH] D12800: [ValueTracking] Teach isKnownNonZero about monotonically increasing PHIs

[James Molloy via llvm-commits]

jmolloy added a comment.

> Adding the analogous case isKnownNonNegative (aka, using it to set the sign bit in computeKnownBits) would be a really good idea. An increasing induction variable starting at zero is pretty much the ideal canonical induction variable and we should exploit that.


It looks like this should already be handled in computeKnownBits (ValueTracking.cpp:1277).


Repository:
  rL LLVM

http://reviews.llvm.org/D12800