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Date:   Mon, 19 Aug 2019 08:23:13 -0500
From:   Segher Boessenkool <segher@kernel.crashing.org>
To:     Christophe Leroy <christophe.leroy@c-s.fr>
Cc:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 3/3] powerpc: use __builtin_trap() in BUG/WARN macros.
Message-ID: <20190819132313.GH31406@gate.crashing.org>
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On Mon, Aug 19, 2019 at 01:06:31PM +0000, Christophe Leroy wrote:
> Note that we keep using an assembly text using "twi 31, 0, 0" for
> inconditional traps because GCC drops all code after
> __builtin_trap() when the condition is always true at build time.

As I said, it can also do this for conditional traps, if it can prove
the condition is always true.

Can you put the bug table asm *before* the __builtin_trap maybe?  That
should make it all work fine...  If you somehow can tell what machine
instruction is that trap, anyway.


Segher