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From: David Chisnall <theraven@freebsd.org>
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Date: Mon, 23 Jul 2012 20:53:22 +0100
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To: Konstantin Belousov <kostikbel@gmail.com>
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Cc: Kim Culhan <w8hdkim@gmail.com>, freebsd-current@freebsd.org,
	Dimitry Andric <dim@freebsd.org>
Subject: Re: -current build failure
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On 23 Jul 2012, at 20:18, Konstantin Belousov wrote:

> Longer description is that pc_curthread is offset 0 if %gs-based.
> The dereferenced pointer point to the struct thread, which contains
> td_proc pointer at offset 8. Instead, clang seems to dereference
> td_proc from offset 8 based on %gs, or something similar.

This appears to be a bug in the LLVM X86 back end.  It is performing an =
invalid fold of the two loads.  I have filed this bug:

http://llvm.org/bugs/show_bug.cgi?id=3D13438

David=