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Merge branch 'core-types-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull hweight type fix from Ingo Molnar:
 "This lone commit makes sure that __const_hweight8() is unsigned, which
  addresses a build warning if code is built with -Wsign-compare.

  I hope the type cast in this cleanup is fine - another option would be
  to eliminate the double unary negation and use a construct with more
  obvious integer type characteristics, along the lines of:

        ((w) & (1ULL << 1) ? 1U : 0U)

  or so"

* 'core-types-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  bitops: Fix signedness of compile-time hweight implementations
Linus Torvalds 11 年之前
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共有 1 個文件被更改,包括 9 次插入8 次删除
  1. 9 8
      include/asm-generic/bitops/const_hweight.h

+ 9 - 8
include/asm-generic/bitops/const_hweight.h

@@ -5,14 +5,15 @@
  * Compile time versions of __arch_hweightN()
  */
 #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)))	)
+	((unsigned int)			\
+	 ((!!((w) & (1ULL << 0))) +	\
+	  (!!((w) & (1ULL << 1))) +	\
+	  (!!((w) & (1ULL << 2))) +	\
+	  (!!((w) & (1ULL << 3))) +	\
+	  (!!((w) & (1ULL << 4))) +	\
+	  (!!((w) & (1ULL << 5))) +	\
+	  (!!((w) & (1ULL << 6))) +	\
+	  (!!((w) & (1ULL << 7)))))
 
 #define __const_hweight16(w) (__const_hweight8(w)  + __const_hweight8((w)  >> 8 ))
 #define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16))