[PATCH] D48529: [DAGCombiner][X86][PowerPC][ARM][AMDGPU][Sparc] Replace (sub C, X) with (xor X, C) if there is no chance of a borrow during the subtraction.

[Sanjay Patel via Phabricator via llvm-commits]

spatel added reviewers: nemanjai, kbarton, sfertile, syzaara.
spatel added a comment.

Looks like a generally good fold to me - prefer bitwise logic because that's the cheapest ALU op possible.

Adding some PowerPC reviewers to see if they're ok with the regression or if that must be fixed first.


Repository:
  rL LLVM

https://reviews.llvm.org/D48529