6 files changed, 34 insertions, 42 deletions

diff --git a/lib/libc/string/ffs.c b/lib/libc/string/ffs.c
index 738ef90ce091..c011b3390612 100644
--- a/lib/libc/string/ffs.c
+++ b/lib/libc/string/ffs.c
@@ -3,6 +3,10 @@
  *
  * Copyright (c) 1990, 1993
  *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2023 The FreeBSD Foundation
+ *
+ * Portions of this software were developed by Robert Clausecker
+ * <fuz@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -43,11 +47,5 @@ __FBSDID("$FreeBSD$");
 int
 ffs(int mask)
 {
-	int bit;
-
-	if (mask == 0)
-		return(0);
-	for (bit = 1; !(mask & 1); bit++)
-		mask = (unsigned int)mask >> 1;
-	return (bit);
+	return (__builtin_ffs(mask));
 }
diff --git a/lib/libc/string/ffsl.c b/lib/libc/string/ffsl.c
index dbd894b9655b..6e1ac8ec45c1 100644
--- a/lib/libc/string/ffsl.c
+++ b/lib/libc/string/ffsl.c
@@ -3,6 +3,10 @@
  *
  * Copyright (c) 1990, 1993
  *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2023 The FreeBSD Foundation
+ *
+ * Portions of this software were developed by Robert Clausecker
+ * <fuz@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -40,11 +44,5 @@ __FBSDID("$FreeBSD$");
 int
 ffsl(long mask)
 {
-	int bit;
-
-	if (mask == 0)
-		return (0);
-	for (bit = 1; !(mask & 1); bit++)
-		mask = (unsigned long)mask >> 1;
-	return (bit);
+	return (__builtin_ffsl(mask));
 }
diff --git a/lib/libc/string/ffsll.c b/lib/libc/string/ffsll.c
index 91886de2f127..b945658b9008 100644
--- a/lib/libc/string/ffsll.c
+++ b/lib/libc/string/ffsll.c
@@ -3,6 +3,10 @@
  *
  * Copyright (c) 1990, 1993
  *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2023 The FreeBSD Foundation
+ *
+ * Portions of this software were developed by Robert Clausecker
+ * <fuz@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -40,11 +44,5 @@ __FBSDID("$FreeBSD$");
 int
 ffsll(long long mask)
 {
-	int bit;
-
-	if (mask == 0)
-		return (0);
-	for (bit = 1; !(mask & 1); bit++)
-		mask = (unsigned long long)mask >> 1;
-	return (bit);
+	return (__builtin_ffsll(mask));
 }
diff --git a/lib/libc/string/fls.c b/lib/libc/string/fls.c
index d9edc41f9599..3c4719776778 100644
--- a/lib/libc/string/fls.c
+++ b/lib/libc/string/fls.c
@@ -3,6 +3,10 @@
  *
  * Copyright (c) 1990, 1993
  *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2023 The FreeBSD Foundation
+ *
+ * Portions of this software were developed by Robert Clausecker
+ * <fuz@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -32,6 +36,7 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include <limits.h>
 #include <strings.h>
 
 /*
@@ -40,11 +45,5 @@ __FBSDID("$FreeBSD$");
 int
 fls(int mask)
 {
-	int bit;
-
-	if (mask == 0)
-		return (0);
-	for (bit = 1; mask != 1; bit++)
-		mask = (unsigned int)mask >> 1;
-	return (bit);
+	return (mask == 0 ? 0 : CHAR_BIT * sizeof(mask) - __builtin_clz(mask));
 }
diff --git a/lib/libc/string/flsl.c b/lib/libc/string/flsl.c
index 60370cf7d832..f5280b77a4e2 100644
--- a/lib/libc/string/flsl.c
+++ b/lib/libc/string/flsl.c
@@ -3,6 +3,11 @@
  *
  * Copyright (c) 1990, 1993
  *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2023 The FreeBSD Foundation
+
+ *
+ * Portions of this software were developed by Robert Clausecker
+ * <fuz@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -32,6 +37,7 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include <limits.h>
 #include <strings.h>
 
 /*
@@ -40,11 +46,5 @@ __FBSDID("$FreeBSD$");
 int
 flsl(long mask)
 {
-	int bit;
-
-	if (mask == 0)
-		return (0);
-	for (bit = 1; mask != 1; bit++)
-		mask = (unsigned long)mask >> 1;
-	return (bit);
+	return (mask == 0 ? 0 : CHAR_BIT * sizeof(mask) - __builtin_clzl(mask));
 }
diff --git a/lib/libc/string/flsll.c b/lib/libc/string/flsll.c
index 275aaa0e2e15..ab504b8e592f 100644
--- a/lib/libc/string/flsll.c
+++ b/lib/libc/string/flsll.c
@@ -3,6 +3,10 @@
  *
  * Copyright (c) 1990, 1993
  *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2023 The FreeBSD Foundation
+ *
+ * Portions of this software were developed by Robert Clausecker
+ * <fuz@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -32,6 +36,7 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include <limits.h>
 #include <strings.h>
 
 /*
@@ -40,11 +45,5 @@ __FBSDID("$FreeBSD$");
 int
 flsll(long long mask)
 {
-	int bit;
-
-	if (mask == 0)
-		return (0);
-	for (bit = 1; mask != 1; bit++)
-		mask = (unsigned long long)mask >> 1;
-	return (bit);
+	return (mask == 0 ? 0 : CHAR_BIT * sizeof(mask) - __builtin_clzll(mask));
 }