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From: Paul Menzel <pmenzel@molgen.mpg.de>
To: Christophe Leroy <christophe.leroy@csgroup.eu>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev
Subject: Re: [PATCH v2] lib/zlib_inflate/inffast: Check config in C to avoid unused function warning
Date: Mon, 20 Sep 2021 10:47:28 +0200	[thread overview]
Message-ID: <dcae41fe-b09b-eb0c-f518-f49e2ea36aa8@molgen.mpg.de> (raw)
In-Reply-To: <00f8d7d7-cb13-203e-5a37-aee34a3258ff@csgroup.eu>

Dear Christophe,


Thank you for the review.

Am 20.09.21 um 10:36 schrieb Christophe Leroy:
> 
> 
> Le 20/09/2021 à 09:46, Paul Menzel a écrit :
>> Building Linux for ppc64le with Ubuntu clang version 12.0.0-3ubuntu1~21.04.1
>> shows the warning below.
>>
>>      arch/powerpc/boot/inffast.c:20:1: warning: unused function 'get_unaligned16' [-Wunused-function]
>>      get_unaligned16(const unsigned short *p)
>>      ^
>>      1 warning generated.
>>
>> Fix it, by moving the check from the preprocessor to C, so the compiler
>> sees the use.
>>
>> Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
>> ---
>>   lib/zlib_inflate/inffast.c | 7 ++-----
>>   1 file changed, 2 insertions(+), 5 deletions(-)
>>
>> diff --git a/lib/zlib_inflate/inffast.c b/lib/zlib_inflate/inffast.c
>> index f19c4fbe1be7..fb87a3120f0f 100644
>> --- a/lib/zlib_inflate/inffast.c
>> +++ b/lib/zlib_inflate/inffast.c
>> @@ -254,11 +254,8 @@ void inflate_fast(z_streamp strm, unsigned start)
>>               sfrom = (unsigned short *)(from);
>>               loops = len >> 1;
>>               do
>> -#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
>> -                *sout++ = *sfrom++;
>> -#else
>> -                *sout++ = get_unaligned16(sfrom++);
>> -#endif
>> +                *sout++ = 
>> IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ?
>> +                *sfrom++ : get_unaligned16(sfrom++);
> 
> I think it would be more readable as
> 
> do {
>          if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
>                  *sout++ = *sfrom++;
>          else
>                  *sout++ = get_unaligned16(sfrom++);
> } while (--loops);

I prefer the ternary operator, as it’s less lines, and it’s clear, that 
only the variable assignment is affected by the condition. But as style 
is subjective, I sent v3.

>>               while (--loops);
>>               out = (unsigned char *)sout;
>>               from = (unsigned char *)sfrom;


Kind regards,

Paul

WARNING: multiple messages have this Message-ID
From: Paul Menzel <pmenzel@molgen.mpg.de>
To: Christophe Leroy <christophe.leroy@csgroup.eu>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>
Cc: llvm@lists.linux.dev, Zhen Lei <thunder.leizhen@huawei.com>,
	linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2] lib/zlib_inflate/inffast: Check config in C to avoid unused function warning
Date: Mon, 20 Sep 2021 10:47:28 +0200	[thread overview]
Message-ID: <dcae41fe-b09b-eb0c-f518-f49e2ea36aa8@molgen.mpg.de> (raw)
In-Reply-To: <00f8d7d7-cb13-203e-5a37-aee34a3258ff@csgroup.eu>

Dear Christophe,


Thank you for the review.

Am 20.09.21 um 10:36 schrieb Christophe Leroy:
> 
> 
> Le 20/09/2021 à 09:46, Paul Menzel a écrit :
>> Building Linux for ppc64le with Ubuntu clang version 12.0.0-3ubuntu1~21.04.1
>> shows the warning below.
>>
>>      arch/powerpc/boot/inffast.c:20:1: warning: unused function 'get_unaligned16' [-Wunused-function]
>>      get_unaligned16(const unsigned short *p)
>>      ^
>>      1 warning generated.
>>
>> Fix it, by moving the check from the preprocessor to C, so the compiler
>> sees the use.
>>
>> Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
>> ---
>>   lib/zlib_inflate/inffast.c | 7 ++-----
>>   1 file changed, 2 insertions(+), 5 deletions(-)
>>
>> diff --git a/lib/zlib_inflate/inffast.c b/lib/zlib_inflate/inffast.c
>> index f19c4fbe1be7..fb87a3120f0f 100644
>> --- a/lib/zlib_inflate/inffast.c
>> +++ b/lib/zlib_inflate/inffast.c
>> @@ -254,11 +254,8 @@ void inflate_fast(z_streamp strm, unsigned start)
>>               sfrom = (unsigned short *)(from);
>>               loops = len >> 1;
>>               do
>> -#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
>> -                *sout++ = *sfrom++;
>> -#else
>> -                *sout++ = get_unaligned16(sfrom++);
>> -#endif
>> +                *sout++ = 
>> IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ?
>> +                *sfrom++ : get_unaligned16(sfrom++);
> 
> I think it would be more readable as
> 
> do {
>          if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
>                  *sout++ = *sfrom++;
>          else
>                  *sout++ = get_unaligned16(sfrom++);
> } while (--loops);

I prefer the ternary operator, as it’s less lines, and it’s clear, that 
only the variable assignment is affected by the condition. But as style 
is subjective, I sent v3.

>>               while (--loops);
>>               out = (unsigned char *)sout;
>>               from = (unsigned char *)sfrom;


Kind regards,

Paul

  reply	other threads:[~2021-09-20  8:47 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-20  7:46 [PATCH v2] lib/zlib_inflate/inffast: Check config in C to avoid unused function warning Paul Menzel
2021-09-20  7:46 ` Paul Menzel
2021-09-20  8:36 ` Christophe Leroy
2021-09-20  8:36   ` Christophe Leroy
2021-09-20  8:47   ` Paul Menzel [this message]
2021-09-20  8:47     ` Paul Menzel

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