Date: Mon, 5 Jan 2026 03:31:08 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Robert Clausecker <fuz@freebsd.org> Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-branches@freebsd.org Subject: Re: git: 9c68745a5064 - stable/15 - libc/amd64: fix stpncpy.S again Message-ID: <aVsUXGL1c3xoH37A@kib.kiev.ua> In-Reply-To: <695a69f1.39da1.5b9f90d9@gitrepo.freebsd.org>
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On Sun, Jan 04, 2026 at 01:24:01PM +0000, Robert Clausecker wrote: > The branch stable/15 has been updated by fuz: > > URL: https://cgit.FreeBSD.org/src/commit/?id=9c68745a50640ccff37565e3cbfe53dddc18d7d3 > > commit 9c68745a50640ccff37565e3cbfe53dddc18d7d3 > Author: Robert Clausecker <fuz@FreeBSD.org> > AuthorDate: 2025-12-18 23:37:33 +0000 > Commit: Robert Clausecker <fuz@FreeBSD.org> > CommitDate: 2026-01-04 13:22:51 +0000 > > libc/amd64: fix stpncpy.S again > > The previous fix introduced a regression on machines without the BMI1 > instruction set extension. The TZCNT instruction used in this function > behaves different on old machines when the source operand is zero, but > the code was originally designed to never trigger this case. The bug > fix caused this case to be possible, leading to a regression on > sufficiently old hardware. > > Fix the code by messing with things such that the source operand is > never zero. > > PR: 291720 > Fixes: 66eb78377bf109af1d9e25626bf254b4369436ec > Tested by: cy > Approved by: markj (mentor) > Differential Revision: https://reviews.freebsd.org/D54303 > > (cherry picked from commit 2f83319214d9adb8ab7a77e35d1014658b3f9cae) Why do you perform insta-MFC? Even for bug fixes, the strict policy is to have at least 3 days probation for the change in HEAD.home | help
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