Hi Andi, [auto build test WARNING on v4.5-rc1] [also build test WARNING on next-20160128] [if your patch is applied to the wrong git tree, please drop us a note to help improving the system]
url: https://github.com/0day-ci/linux/commits/Andi-Kleen/Optimize-int_sqrt-for-small-values-for-faster-idle/20160129-054629 config: x86_64-randconfig-x015-01270835 (attached as .config) reproduce: # save the attached .config to linux build tree make ARCH=x86_64 Note: it may well be a FALSE warning. FWIW you are at least aware of it now. http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings All warnings (new ones prefixed by >>): lib/int_sqrt.c: In function 'int_sqrt': >> lib/int_sqrt.c:25:6: warning: 'm' may be used uninitialized in this function >> [-Wmaybe-uninitialized] if (m <= 0xff) ^ vim +/m +25 lib/int_sqrt.c 9 #include <linux/export.h> 10 11 /** 12 * int_sqrt - rough approximation to sqrt 13 * @x: integer of which to calculate the sqrt 14 * 15 * A very rough approximation to the sqrt() function. 16 */ 17 unsigned long int_sqrt(unsigned long x) 18 { 19 unsigned long b, m, y = 0; 20 21 if (x <= 1) 22 return x; 23 24 if (x <= 0xffff) { > 25 if (m <= 0xff) 26 m = 1UL << (8 - 2); 27 else 28 m = 1UL << (16 - 2); 29 } else if (x <= 0xffffffff) 30 m = 1UL << (32 - 2); 31 else 32 m = 1UL << (BITS_PER_LONG - 2); 33 while (m != 0) { --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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