git: b7cbf741d554 - main - libkern: avoid local var in order_base_2()

The branch main has been updated by dougm:

URL: https://cgit.FreeBSD.org/src/commit/?id=b7cbf741d55468ba34305a14ac3acc1c286af034

commit b7cbf741d55468ba34305a14ac3acc1c286af034
Author:     Doug Moore <dougm@FreeBSD.org>
AuthorDate: 2024-09-27 23:43:07 +0000
Commit:     Doug Moore <dougm@FreeBSD.org>
CommitDate: 2024-09-27 23:43:07 +0000

    libkern: avoid local var in order_base_2()
    
    order_base_2(n) is implemented with a variable, which keeps it from
    being used at file scope. Implement it instead as ilog2(2*n-1), which
    produces a different result when 2*n overflows, which appears unlikely
    in practice.
    
    Reviewed by:    bz
    Differential Revision:  https://reviews.freebsd.org/D46826
---
 sys/sys/libkern.h | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/sys/sys/libkern.h b/sys/sys/libkern.h
index 64744f57b5c3..ad64d0fb0a57 100644
--- a/sys/sys/libkern.h
+++ b/sys/sys/libkern.h
@@ -227,10 +227,7 @@ ilog2_long_long(long long n)
 
 #define	ilog2(n) (__builtin_constant_p(n) ? ilog2_const(n) : ilog2_var(n))
 #define	rounddown_pow_of_two(n)	((__typeof(n))1 << ilog2(n))
-#define	order_base_2(n) ({			\
-	__typeof(n) _n = (n);			\
-	_n == 1 ? 0 : 1 + ilog2(_n - 1);	\
-})
+#define order_base_2(n) ilog2(2*(n)-1)
 #define	roundup_pow_of_two(n)	((__typeof(n))1 << order_base_2(n))
 
 #define	bitcount64(x)	__bitcount64((uint64_t)(x))