[all-commits] [llvm/llvm-project] f8b01d: Reland 293e8fa13d3f05e993771577a4c022deee5cbf6e

[Vy Nguyen via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: f8b01d54c31547f3ecb25fb8a1912183026bffa7
      https://github.com/llvm/llvm-project/commit/f8b01d54c31547f3ecb25fb8a1912183026bffa7
  Author: Vy Nguyen <vyng at google.com>
  Date:   2021-03-05 (Fri, 05 Mar 2021)

  Changed paths:
    M llvm/include/llvm/Support/Host.h
    M llvm/lib/Support/Host.cpp
    M llvm/tools/llvm-exegesis/lib/X86/Target.cpp

  Log Message:
  -----------
  Reland 293e8fa13d3f05e993771577a4c022deee5cbf6e
    [llvm-exegesis] Disable the LBR check on AMD

    https://bugs.llvm.org/show_bug.cgi?id=48918

    The bug reported a hang (or very very slow runtime) on a Zen2. Unfortunately, we don't have the hardware right now to debug it and I was not able to reproduce the bug on a HSW.
    Theory we've got is that the lbr-checking code could be confused on AMD.

    Differential Revision: https://reviews.llvm.org/D97504

New change:
 - Surround usages of x86 helper in llvm-exegesis/X86/Target.cpp with ifdef
 - Fix bug which caused the caller of getVendorSignature to not have a copy of EAX that it expected.