x86: further speed-up to hweight{32,64}()

According to Linux commit 0136611c62 ("optimize hweight64 for x86_64")
this is a further improvement over the variant using only bitwise
operations. It's also a slight further code size reduction.

Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index 4b8b07b5496b4131c579d26de402dcb13e5d6406..f502d765ba3d7a18d9474ee4bf66fa873dbef722 100644 (file)
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -12,6 +12,7 @@ config X86
        select HAS_CPUFREQ
        select HAS_EHCI
        select HAS_EX_TABLE
+       select HAS_FAST_MULTIPLY
        select HAS_GDBSX
        select HAS_IOPORTS
        select HAS_KEXEC