[all-commits] [llvm/llvm-project] 893745: [InstCombine] add tests for sext-of-trunc-of-lshr; ...

[RotateRight via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 8937450e8581a8a135c61ff083828e6603755ef5
      https://github.com/llvm/llvm-project/commit/8937450e8581a8a135c61ff083828e6603755ef5
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2021-06-04 (Fri, 04 Jun 2021)

  Changed paths:
    M llvm/test/Transforms/InstCombine/lshr-trunc-sext-to-ashr-sext.ll

  Log Message:
  -----------
  [InstCombine] add tests for sext-of-trunc-of-lshr; NFC


  Commit: 23a116c8c446f82ec5e2d2337c3253d0dc9c75b5
      https://github.com/llvm/llvm-project/commit/23a116c8c446f82ec5e2d2337c3253d0dc9c75b5
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2021-06-04 (Fri, 04 Jun 2021)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
    M llvm/test/Transforms/InstCombine/lshr-trunc-sext-to-ashr-sext.ll

  Log Message:
  -----------
  [InstCombine] convert lshr to ashr to eliminate cast op

This is similar to b865eead7657 ( D103617 ) and fixes:
https://llvm.org/PR50575

41b71f718b94c6f12b did this and more (noted with TODO
comments in the tests), but it didn't handle the case
where the destination is narrower than the source, so
it got reverted.

This is a simple match-and-replace. If there's evidence
that the TODO cases are useful, we can revisit/extend.


Compare: https://github.com/llvm/llvm-project/compare/d84ed15c6496...23a116c8c446