From 5b5a2f6b922bacdcd6dd2861381d91cd168edea6 Mon Sep 17 00:00:00 2001 From: Frank Barchard Date: Thu, 9 Apr 2026 16:30:09 -0700 Subject: [PATCH] Fix 'ghost AVX512' detection on Alder Lake CPUs Adds a check for the AVX512F feature bit (cpu_info7[1] & 0x00010000) before enabling AVX512 features. Alder Lake CPUs can report OS support for YMM/ZMM but not actually support AVX512F, leading to incorrect capability detection and crashes. Bug: libyuv:500318522 Change-Id: I84167ee3fcfc7a2572afba148bbb275bd3ccb1e5 Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/7746229 Commit-Queue: Frank Barchard Reviewed-by: Dale Curtis --- source/cpu_id.cc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/source/cpu_id.cc b/source/cpu_id.cc index 8ad35acb1..dc7a1f98c 100644 --- a/source/cpu_id.cc +++ b/source/cpu_id.cc @@ -428,7 +428,7 @@ static SAFEBUFFERS int GetCpuFlags(void) { cpu_info |= ((cpu_amdinfo21[0] & 0x00008000) ? kCpuHasERMS : 0); // Detect AVX512bw - if ((GetXCR0() & 0xe0) == 0xe0) { + if ((GetXCR0() & 0xe0) == 0xe0 && (cpu_info7[1] & 0x00010000)) { cpu_info |= ((cpu_info7[1] & 0x40000000) ? kCpuHasAVX512BW : 0) | ((cpu_info7[1] & 0x80000000) ? kCpuHasAVX512VL : 0) | ((cpu_info7[2] & 0x00000002) ? kCpuHasAVX512VBMI : 0) |