[all-commits] [llvm/llvm-project] 77f2f3: [InstCombine] Generalize (icmp sgt (1 << Y), -1) -...

[Craig Topper via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 77f2f34d696b77fe5bf05afbe7386966b6bcc8ba
      https://github.com/llvm/llvm-project/commit/77f2f34d696b77fe5bf05afbe7386966b6bcc8ba
  Author: Craig Topper <craig.topper at sifive.com>
  Date:   2023-01-15 (Sun, 15 Jan 2023)

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

  Log Message:
  -----------
  [InstCombine] Generalize (icmp sgt (1 << Y), -1) -> (icmp ne Y, BitWidth-1) to any negative constant.

Similar for the sle version which will be canonicalized to slt first.

Alive2 proof as implemented: https://alive2.llvm.org/ce/z/_YawdM

@spatel's  original Alive2: https://alive2.llvm.org/ce/z/3YB2vs

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D141773