[all-commits] [llvm/llvm-project] 27e9f0: [KnownBits] Merge the minimum shift amount and lea...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 27e9f0f95ef7b144d008bc1cf1459dced6cb5842
      https://github.com/llvm/llvm-project/commit/27e9f0f95ef7b144d008bc1cf1459dced6cb5842
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2020-11-13 (Fri, 13 Nov 2020)

  Changed paths:
    M llvm/lib/Support/KnownBits.cpp

  Log Message:
  -----------
  [KnownBits] Merge the minimum shift amount and leading/trailing shift value bits handling.

By starting with the source shift value minimum leading/trailing bits, we can then add the minimum known shift amount to more accurately predict the minimum leading/trailing bits of the result.

This is currently only covered by the exhaustive unit tests in KnownBitsTests.cpp, but will help with some of the regressions encountered in D90479 (PR44526).