[all-commits] [llvm/llvm-project] 82921b: [Support] Don't check XCR0 when detecting avx512 o...

[Florian Hahn via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 82921bf2baed96b700f90b090d5dc2530223d9c0
      https://github.com/llvm/llvm-project/commit/82921bf2baed96b700f90b090d5dc2530223d9c0
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2019-11-21 (Thu, 21 Nov 2019)

  Changed paths:
    M llvm/lib/Support/Host.cpp

  Log Message:
  -----------
  [Support] Don't check XCR0 when detecting avx512 on Darwin.

Darwin lazily saves the AVX512 context on first use [1]: instead of checking
that it already does to figure out if the OS supports AVX512, trust that
the kernel will do the right thing and always assume the context save
support is available.

[1] https://github.com/apple/darwin-xnu/blob/xnu-4903.221.2/osfmk/i386/fpu.c#L174

Reviewers: ab, RKSimon, craig.topper

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D70453