Summary: On darwin/amd64, it is not adequate to use OSXSAVE
bits to determine AVX512 availabilty. The reason is involved.
See github issue for details.
The fix consists of implementing Apple's recommended approach
using the process commpage cpu_capabilities bits to determine
availability of AVX512.
Fixesgolang/go#43089
Change-Id: I1ba89965498863d268fbf2e427dbfd6429c7409f
Reviewed-on: https://go-review.googlesource.com/c/sys/+/285572
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
It uses __get_cpuid_count, provided by cpuid.h.
The xgetbv is implemented after its counterpart in cpu_x86.s.
Change-Id: I97624d7da67ab4ec3c9a53b0bfc4dfcdf7d12c87
Reviewed-on: https://go-review.googlesource.com/116155
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This CL introduces a new cpu package for CPU/platform feature detection.
The cpu package is basically a copy of `internal/cpu` of the standard library.
Revision: bf86aec25972f3a100c3aa58a6abcbcc35bdea49
This CL does not export ARM64 and PPC64 feature detection since at the moment
ARM64/PPC64 requires standard library support.
Updates golang/go#24843
Change-Id: I11bc1ca60b116e902c941b5887c00870dbb1f899
Reviewed-on: https://go-review.googlesource.com/107015
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
