[all-commits] [llvm/llvm-project] e8e852: [InstCombine] Add tests for tranforming `(icmp pre...

[goldsteinn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: e8e8528085ebdb2fb4395f07abdf6bcaf0348630
      https://github.com/llvm/llvm-project/commit/e8e8528085ebdb2fb4395f07abdf6bcaf0348630
  Author: Noah Goldstein <goldstein.w.n at gmail.com>
  Date:   2023-06-05 (Mon, 05 Jun 2023)

  Changed paths:
    A llvm/test/Transforms/InstCombine/icmp-shl.ll

  Log Message:
  -----------
  [InstCombine] Add tests for tranforming `(icmp pred (shl {nsw and/or nuw} X, Y), C)`; NFC

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D145340


  Commit: 73ce343125c5c86373ac3f883932f4ddbc2d307a
      https://github.com/llvm/llvm-project/commit/73ce343125c5c86373ac3f883932f4ddbc2d307a
  Author: Noah Goldstein <goldstein.w.n at gmail.com>
  Date:   2023-06-05 (Mon, 05 Jun 2023)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
    M llvm/test/Transforms/InstCombine/icmp-shl.ll

  Log Message:
  -----------
  [InstCombine] Add transform `(icmp pred (shl {nsw and/or nuw} X, Y), C)` -> `(icmp pred X, C)`

Three new transforms:
    1) `(icmp pred (shl nsw nuw X, Y), C)` [if `C <= 0`] -> `(icmp pred X, C)`
        - ugt: https://alive2.llvm.org/ce/z/K_57J_
        - sgt: https://alive2.llvm.org/ce/z/BL8u_a
        - sge: https://alive2.llvm.org/ce/z/yZZVYz
        - uge: https://alive2.llvm.org/ce/z/R4jwwJ
        - ule: https://alive2.llvm.org/ce/z/-gbmth
        - sle: https://alive2.llvm.org/ce/z/ycZVsh
        - slt: https://alive2.llvm.org/ce/z/4MzHYm
        - sle: https://alive2.llvm.org/ce/z/fgNfex
        - ult: https://alive2.llvm.org/ce/z/cXfvH5
        - eq : https://alive2.llvm.org/ce/z/sZh_Ti
        - ne : https://alive2.llvm.org/ce/z/UrqSWA

    2) `(icmp eq/ne (shl {nsw|nuw} X, Y), 0)` -> `(icmp eq/ne X, 0)`
        - eq+nsw: https://alive2.llvm.org/ce/z/aSJN6D
        - eq+nuw: https://alive2.llvm.org/ce/z/r2_-br
        - ne+nuw: https://alive2.llvm.org/ce/z/RkETtu
        - ne+nsw: https://alive2.llvm.org/ce/z/8iSfW3

    3) `(icmp slt (shl nsw X, Y), 0/1)` -> `(icmp pred X, 0/1)`
       `(icmp sgt (shl nsw X, Y), 0/-1)` -> `(icmp pred X, 0/-1)`
        - slt: https://alive2.llvm.org/ce/z/eZYRan
        - sgt: https://alive2.llvm.org/ce/z/QQeP26

    Transform 3) is really sle/slt/sge/sgt with 0, but sle/sge
    canonicalize to slt/sgt respectively so its implemented as such.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D145341


Compare: https://github.com/llvm/llvm-project/compare/b14f95b988bb...73ce343125c5