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Date:      Sat, 5 Oct 2019 09:28:53 -0600
From:      Warner Losh <imp@bsdimp.com>
To:        freebsd-arch@freebsd.org
Subject:   New CPUTYPE default for i386 port
Message-ID:  <CANCZdfoFPsjyuCTfm0dQhz%2BsgVHLEvMA8-E3-Yhciz67qdoKvw@mail.gmail.com>

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For a variety of reasons,  the time has come to change the default code
generation arch from i486 to i686 on our i386 port. No actual code removal
is planned as part of this effort. Only the default is doing changed for
clang.

The practical upshot of this for our i386 users will be zero for almost
everybody. For the tiny sliver of people planning to deploy FreeBSD on a
i486 or i586 core, a simple addition of CPUTYPE=xxxx to /etc/make.conf is
all that is needed for the src side of things. They will need to setup
their own poudriere instance and create their own pkg repo to build
whatever packages are required for their deployment.

It's my belief that even in the trailing edge long tail embedded deployment
segment of our user base this will cause no issues. All deployments there
I'm aware of have moved of i486 class CPUs and the one 586 class core
deployment I know of has no plans to update that to FreeBSD 11, let alone
newer.

There are a number of advantages to doing this which have been articulated
at length in other discussions. Briefly we get better code generation for
CPUs people use and we avoid some test failures in llvm 9.0 because i486
doesn't have 64-bot atomics.

Comments?

Warner



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