x86/64: Adjust types of temporaries used by ffs()/fls()/fls64()

The 64-bit special cases of the former two (the thrird one is
64-bit only anyway) don't need to use "long" temporaries, as the
result will always fit in a 32-bit variable, and the functions
return plain "int". This avoids a few REX prefixes, i.e.
minimally reduces code size.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/504DE550020000780009A258@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 4 insertions, 6 deletions

diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h
index 72f5009deb5a..ebaee695394e 100644
--- a/arch/x86/include/asm/bitops.h
+++ b/arch/x86/include/asm/bitops.h
@@ -417,10 +417,9 @@ static inline int ffs(int x)
          * We cannot do this on 32 bits because at the very least some
          * 486 CPUs did not behave this way.
          */
-        long tmp = -1;
         asm("bsfl %1,%0"
             : "=r" (r)
-            : "rm" (x), "0" (tmp));
+            : "rm" (x), "0" (-1));
 #elif defined(CONFIG_X86_CMOV)
         asm("bsfl %1,%0\n\t"
             "cmovzl %2,%0"
@@ -459,10 +458,9 @@ static inline int fls(int x)
          * We cannot do this on 32 bits because at the very least some
          * 486 CPUs did not behave this way.
          */
-        long tmp = -1;
         asm("bsrl %1,%0"
             : "=r" (r)
-            : "rm" (x), "0" (tmp));
+            : "rm" (x), "0" (-1));
 #elif defined(CONFIG_X86_CMOV)
         asm("bsrl %1,%0\n\t"
             "cmovzl %2,%0"
@@ -490,13 +488,13 @@ static inline int fls(int x)
 #ifdef CONFIG_X86_64
 static __always_inline int fls64(__u64 x)
 {
-        long bitpos = -1;
+        int bitpos = -1;
         /*
          * AMD64 says BSRQ won't clobber the dest reg if x==0; Intel64 says the
          * dest reg is undefined if x==0, but their CPU architect says its
          * value is written to set it to the same as before.
          */
-        asm("bsrq %1,%0"
+        asm("bsrq %1,%q0"
             : "+r" (bitpos)
             : "rm" (x));
         return bitpos + 1;