[all-commits] [llvm/llvm-project] 23b419: [Support] Add KnownBits::icmp helpers.

[Simon Pilgrim via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 23b41986527a3fc5615480a8f7a0b0debd5fcef4
      https://github.com/llvm/llvm-project/commit/23b41986527a3fc5615480a8f7a0b0debd5fcef4
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2021-01-04 (Mon, 04 Jan 2021)

  Changed paths:
    M llvm/include/llvm/Support/KnownBits.h
    M llvm/lib/Support/KnownBits.cpp
    M llvm/unittests/Support/KnownBitsTest.cpp

  Log Message:
  -----------
  [Support] Add KnownBits::icmp helpers.

Check if all possible values for a pair of knownbits give the same icmp result - these are based off the checks performed in InstCombineCompares.cpp and D86578.

Add exhaustive unit test coverage - a followup will update InstCombineCompares.cpp to use this.