From 45929774c3d5c084cc478afba63c77cf67a68bd7 Mon Sep 17 00:00:00 2001
From: khr@golang.org <khr@golang.org>
Date: Wed, 18 Feb 2026 09:09:57 -0800
Subject: [PATCH] internal/runtime/gc/scan: require popcnt for x86

The GOAMD64=v1 test disables popcnt instructions, which is a feature
this package's amd64 assembly uses.

Fixes #77674

Change-Id: I7be9bb665838f5da50275f96ef3df398412bb44a
Reviewed-on: https://go-review.googlesource.com/c/go/+/746640
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
---

diff --git a/src/internal/runtime/gc/scan/scan_amd64.go b/src/internal/runtime/gc/scan/scan_amd64.go
index c03021c7d4..544b237770 100644
--- a/src/internal/runtime/gc/scan/scan_amd64.go
+++ b/src/internal/runtime/gc/scan/scan_amd64.go
@@ -39,4 +39,5 @@ var avx512ScanPackedReqsMet = cpu.X86.HasAVX512VL &&
 	cpu.X86.HasGFNI &&
 	cpu.X86.HasAVX512BITALG &&
 	cpu.X86.HasAVX512DQ && // for kmovb, see #79871
-	cpu.X86.HasAVX512VBMI
+	cpu.X86.HasAVX512VBMI &&
+	cpu.X86.HasPOPCNT