[all-commits] [llvm/llvm-project] f4e495: [InstCombine][X86] simplifyX86varShift - convert v...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: f4e495a18e80e3d8e9324a5a54966cf3b9780a61
      https://github.com/llvm/llvm-project/commit/f4e495a18e80e3d8e9324a5a54966cf3b9780a61
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2020-03-18 (Wed, 18 Mar 2020)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
    M llvm/test/Transforms/InstCombine/X86/x86-vector-shifts.ll

  Log Message:
  -----------
  [InstCombine][X86] simplifyX86varShift - convert variable in-range per-element shift amounts to generic shifts (PR40391)

AVX2/AVX512 per-element shifts can be replaced with generic shifts if the shift amounts are guaranteed to be in-range (upper bits are known zero).