[all-commits] [llvm/llvm-project] 546d00: [GlobalISel] ComputeKnownBits - use common KnownBi...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 546d002d7a5d0915ab449a3134b9737edc059378
      https://github.com/llvm/llvm-project/commit/546d002d7a5d0915ab449a3134b9737edc059378
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2020-11-05 (Thu, 05 Nov 2020)

  Changed paths:
    M llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp
    M llvm/test/CodeGen/AMDGPU/GlobalISel/lshr.ll

  Log Message:
  -----------
  [GlobalISel] ComputeKnownBits - use common KnownBits shift handling (PR44526)

Convert GISelKnownBits.computeKnownBitsImpl shift handling to use the common KnownBits implementations, which makes use of the known leading/trailing bits for shifted values in cases where we don't know the shift amount value, as detailed in https://blog.regehr.org/archives/1709

Differential Revision: https://reviews.llvm.org/D90527