* 'hweight_long' include/linux/bitops.h compile warning problem.
@ 2011-06-20 7:59 NamJae Jeon
2011-06-20 13:00 ` Arnd Bergmann
0 siblings, 1 reply; 3+ messages in thread
From: NamJae Jeon @ 2011-06-20 7:59 UTC (permalink / raw)
To: arnd, linux-arch
Hello Arnd
I found compile warning while compiling module when using -Wsign-compare option.
include/linux/bitops.h: In function 'hweight_long':
include/linux/bitops.h:49: warning: signed and unsigned type in
conditional expression
I found the reason of this problem that the default return value of
the below macro is signed.
#define __const_hweight8(w) \
( (!!((w) & (1ULL << 0))) + \
(!!((w) & (1ULL << 1))) + \
(!!((w) & (1ULL << 2))) + \
(!!((w) & (1ULL << 3))) + \
(!!((w) & (1ULL << 4))) + \
(!!((w) & (1ULL << 5))) + \
(!!((w) & (1ULL << 6))) + \
(!!((w) & (1ULL << 7))) )
So, I try to add (unsigned long) in __const_hweight8 like this.
#define __const_hweight8(w) (unsigned long ) \
( (!!((w) & (1ULL << 0))) + \
(!!((w) & (1ULL << 1))) + \
(!!((w) & (1ULL << 2))) + \
(!!((w) & (1ULL << 3))) + \
(!!((w) & (1ULL << 4))) + \
(!!((w) & (1ULL << 5))) + \
(!!((w) & (1ULL << 6))) + \
(!!((w) & (1ULL << 7))) )
so, I can't see compile warning after fixing it, Would you plz check this ?
Thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: 'hweight_long' include/linux/bitops.h compile warning problem.
2011-06-20 7:59 'hweight_long' include/linux/bitops.h compile warning problem NamJae Jeon
@ 2011-06-20 13:00 ` Arnd Bergmann
2011-06-21 6:11 ` NamJae Jeon
0 siblings, 1 reply; 3+ messages in thread
From: Arnd Bergmann @ 2011-06-20 13:00 UTC (permalink / raw)
To: NamJae Jeon; +Cc: linux-arch
On Monday 20 June 2011, NamJae Jeon wrote:
> I found compile warning while compiling module when using -Wsign-compare option.
>
> include/linux/bitops.h: In function 'hweight_long':
> include/linux/bitops.h:49: warning: signed and unsigned type in
> conditional expression
>
> I found the reason of this problem that the default return value of
> the below macro is signed.
>
> #define __const_hweight8(w) \
> ( (!!((w) & (1ULL << 0))) + \
> (!!((w) & (1ULL << 1))) + \
> (!!((w) & (1ULL << 2))) + \
> (!!((w) & (1ULL << 3))) + \
> (!!((w) & (1ULL << 4))) + \
> (!!((w) & (1ULL << 5))) + \
> (!!((w) & (1ULL << 6))) + \
> (!!((w) & (1ULL << 7))) )
>
> So, I try to add (unsigned long) in __const_hweight8 like this.
>
> #define __const_hweight8(w) (unsigned long ) \
> ( (!!((w) & (1ULL << 0))) + \
> (!!((w) & (1ULL << 1))) + \
> (!!((w) & (1ULL << 2))) + \
> (!!((w) & (1ULL << 3))) + \
> (!!((w) & (1ULL << 4))) + \
> (!!((w) & (1ULL << 5))) + \
> (!!((w) & (1ULL << 6))) + \
> (!!((w) & (1ULL << 7))) )
>
> so, I can't see compile warning after fixing it, Would you plz check this ?
Yes, this looks correct to me. Could you send the change as a proper patch
with your Signed-off-by:?
Arnd
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: 'hweight_long' include/linux/bitops.h compile warning problem.
2011-06-20 13:00 ` Arnd Bergmann
@ 2011-06-21 6:11 ` NamJae Jeon
0 siblings, 0 replies; 3+ messages in thread
From: NamJae Jeon @ 2011-06-21 6:11 UTC (permalink / raw)
To: Arnd Bergmann, linux-kernel, linux-arch
Hello Arnd.
I attached patch for this warning issue.
If there is a problem of patch, plz reply ....
Thanks.
--------------------------------------------------------------------------------------------------------------------------------------
From 28589ea9aabb080020ab3c79adcecad5d7315f39 Mon Sep 17 00:00:00 2001
From: Namjae Jeon <linkinjeon@gmail.com>
Date: Tue, 21 Jun 2011 14:39:03 +0900
Subject: [PATCH] compilation warning is caused when using hweight_long
with -Wsign-compare option.
Warning message is '
include/linux/bitops.h: In function 'hweight_long':
include/linux/bitops.h:49: warning: signed and unsigned type in
conditional expression
The reason is that the default return value of this macro is signed.
So, need type casting to remove warning.
Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
---
include/asm-generic/bitops/const_hweight.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/include/asm-generic/bitops/const_hweight.h
b/include/asm-generic/bitops/const_hweight.h
index fa2a50b..d91b1aa 100644
--- a/include/asm-generic/bitops/const_hweight.h
+++ b/include/asm-generic/bitops/const_hweight.h
@@ -4,7 +4,7 @@
/*
* Compile time versions of __arch_hweightN()
*/
-#define __const_hweight8(w) \
+#define __const_hweight8(w) (unsigned long) \
( (!!((w) & (1ULL << 0))) + \
(!!((w) & (1ULL << 1))) + \
(!!((w) & (1ULL << 2))) + \
--
1.7.4-rc2
--------------------------------------------------------------------------------------------------------------------------------------
2011/6/20 Arnd Bergmann <arnd@arndb.de>:
> On Monday 20 June 2011, NamJae Jeon wrote:
>> I found compile warning while compiling module when using -Wsign-compare option.
>>
>> include/linux/bitops.h: In function 'hweight_long':
>> include/linux/bitops.h:49: warning: signed and unsigned type in
>> conditional expression
>>
>> I found the reason of this problem that the default return value of
>> the below macro is signed.
>>
>> #define __const_hweight8(w) \
>> ( (!!((w) & (1ULL << 0))) + \
>> (!!((w) & (1ULL << 1))) + \
>> (!!((w) & (1ULL << 2))) + \
>> (!!((w) & (1ULL << 3))) + \
>> (!!((w) & (1ULL << 4))) + \
>> (!!((w) & (1ULL << 5))) + \
>> (!!((w) & (1ULL << 6))) + \
>> (!!((w) & (1ULL << 7))) )
>>
>> So, I try to add (unsigned long) in __const_hweight8 like this.
>>
>> #define __const_hweight8(w) (unsigned long ) \
>> ( (!!((w) & (1ULL << 0))) + \
>> (!!((w) & (1ULL << 1))) + \
>> (!!((w) & (1ULL << 2))) + \
>> (!!((w) & (1ULL << 3))) + \
>> (!!((w) & (1ULL << 4))) + \
>> (!!((w) & (1ULL << 5))) + \
>> (!!((w) & (1ULL << 6))) + \
>> (!!((w) & (1ULL << 7))) )
>>
>> so, I can't see compile warning after fixing it, Would you plz check this ?
>
> Yes, this looks correct to me. Could you send the change as a proper patch
> with your Signed-off-by:?
>
> Arnd
>
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2011-06-20 13:00 ` Arnd Bergmann
2011-06-21 6:11 ` NamJae Jeon
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