Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Mark atomic irq ops raw for 32bit legacy
  x86: Merge show_regs()
  x86: Macroise x86 cache descriptors
  x86-32: clean up rwsem inline asm statements
  x86: Merge asm/atomic_{32,64}.h
  x86: Sync asm/atomic_32.h and asm/atomic_64.h
  x86: Split atomic64_t functions into seperate headers
  x86-64: Modify memcpy()/memset() alternatives mechanism
  x86-64: Modify copy_user_generic() alternatives mechanism
  x86: Lift restriction on the location of FIX_BTMAP_*
  x86, core: Optimize hweight32()

1 files changed, 7 insertions, 0 deletions

diff --git a/lib/hweight.c b/lib/hweight.c
index 389424ecb129..63ee4eb1228d 100644
--- a/lib/hweight.c
+++ b/lib/hweight.c
@@ -11,11 +11,18 @@
 
 unsigned int hweight32(unsigned int w)
 {
+#ifdef ARCH_HAS_FAST_MULTIPLIER
+        w -= (w >> 1) & 0x55555555;
+        w =  (w & 0x33333333) + ((w >> 2) & 0x33333333);
+        w =  (w + (w >> 4)) & 0x0f0f0f0f;
+        return (w * 0x01010101) >> 24;
+#else
         unsigned int res = w - ((w >> 1) & 0x55555555);
         res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
         res = (res + (res >> 4)) & 0x0F0F0F0F;
         res = res + (res >> 8);
         return (res + (res >> 16)) & 0x000000FF;
+#endif
 }
 EXPORT_SYMBOL(hweight32);