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From: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
To: Anders Roxell <anders.roxell@linaro.org>
Cc: natechancellor@gmail.com, ndesaulniers@google.com,
	linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com
Subject: Re: [PATCH v2] mips: lib: uncached: fix non-standard usage of variable 'sp'
Date: Mon, 14 Dec 2020 16:24:47 +0100	[thread overview]
Message-ID: <20201214152447.GC9149@alpha.franken.de> (raw)
In-Reply-To: <20201211102437.3929348-1-anders.roxell@linaro.org>

On Fri, Dec 11, 2020 at 11:24:37AM +0100, Anders Roxell wrote:
> When building mips tinyconfig with clang the following warning show up:
> 
> arch/mips/lib/uncached.c:45:6: warning: variable 'sp' is uninitialized when used here [-Wuninitialized]
>         if (sp >= (long)CKSEG0 && sp < (long)CKSEG2)
>             ^~
> arch/mips/lib/uncached.c:40:18: note: initialize the variable 'sp' to silence this warning
>         register long sp __asm__("$sp");
>                         ^
>                          = 0
> 1 warning generated.
> 
> Rework to make an explicit inline move, instead of the non-standard use
> of specifying registers for local variables. This is what's written
> from the gcc-10 manual [1] about specifying registers for local
> variables:
> 
> "6.47.5.2 Specifying Registers for Local Variables
> .................................................
> [...]
> 
> "The only supported use for this feature is to specify registers for
> input and output operands when calling Extended 'asm' (*note Extended
> Asm::).  [...]".
> 
> [1] https://docs.w3cub.com/gcc~10/local-register-variables
> Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
> ---
>  arch/mips/lib/uncached.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

applied to mips-next.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]

  parent reply	other threads:[~2020-12-14 15:28 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-11 10:24 [PATCH v2] mips: lib: uncached: fix non-standard usage of variable 'sp' Anders Roxell
2020-12-11 19:15 ` Nick Desaulniers
2020-12-11 19:54 ` Maciej W. Rozycki
2020-12-12  5:52   ` Nathan Chancellor
2020-12-14 15:24 ` Thomas Bogendoerfer [this message]
2020-12-20  4:07   ` Naresh Kamboju

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