[all-commits] [llvm/llvm-project] 9b7a0a: [X86] Add support for reusing ZF etc. from locked ...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 9b7a0a50355d5dc8ab3e9598103ef81b00077ff4
      https://github.com/llvm/llvm-project/commit/9b7a0a50355d5dc8ab3e9598103ef81b00077ff4
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2021-04-27 (Tue, 27 Apr 2021)

  Changed paths:
    M llvm/lib/Target/X86/X86InstrInfo.cpp
    M llvm/test/CodeGen/X86/atomic-eflags-reuse.ll
    M llvm/test/CodeGen/X86/atomic-flags.ll

  Log Message:
  -----------
  [X86] Add support for reusing ZF etc. from locked XADD instructions (PR20841)

XADD has the same EFLAGS behaviour as ADD

Reapplies rG2149aa73f640 (after it was reverted at rG535df472b042) - AFAICT rG029e41ec9800 should ensure we correctly tag the LXADD* ops as load/stores - I haven't been able to repro the sanitizer buildbot fails locally so this is a speculative commit.