From: Bruno Haible <bruno@clisp.org>
Date: Thu, 13 Oct 2011 22:48:29 +0000 (+0200)
Subject: ffsl, ffsll: Optimize for GCC.
X-Git-Tag: v0.1~1580
X-Git-Url: http://erislabs.org.uk/gitweb/?a=commitdiff_plain;h=4b3d1ed028029965f1fae63b312dd1e0397f54f8;p=gnulib.git

ffsl, ffsll: Optimize for GCC.

* lib/ffsl.h (FUNC): Use GCC_BUILTIN if defined.
* lib/ffsl.c (GCC_BUILTIN): New macro.
* lib/ffsll.c (GCC_BUILTIN): Likewise.
---

diff --git a/ChangeLog b/ChangeLog
index 8b06b2766..866dfa293 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2011-10-13  Bruno Haible  <bruno@clisp.org>
 
+	ffsl, ffsll: Optimize for GCC.
+	* lib/ffsl.h (FUNC): Use GCC_BUILTIN if defined.
+	* lib/ffsl.c (GCC_BUILTIN): New macro.
+	* lib/ffsll.c (GCC_BUILTIN): Likewise.
+
+2011-10-13  Bruno Haible  <bruno@clisp.org>
+
 	ffs, bcopy, memset: Support symbol renaming via config.h.
 	* lib/ffs.c: Include <config.h>.
 	* lib/bcopy.c: Likewise.
diff --git a/lib/ffsl.c b/lib/ffsl.c
index 0b93796ac..ee99ba7e0 100644
--- a/lib/ffsl.c
+++ b/lib/ffsl.c
@@ -1,3 +1,4 @@
 #define FUNC ffsl
 #define TYPE long int
+#define GCC_BUILTIN __builtin_ffsl
 #include "ffsl.h"
diff --git a/lib/ffsl.h b/lib/ffsl.h
index eb7fead56..9f209123d 100644
--- a/lib/ffsl.h
+++ b/lib/ffsl.h
@@ -31,6 +31,9 @@
 int
 FUNC (TYPE i)
 {
+#if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)) && defined GCC_BUILTIN
+  return GCC_BUILTIN (i);
+#else
   int result = 0;
   unsigned TYPE j = i;
 
@@ -44,4 +47,5 @@ FUNC (TYPE i)
       j >>= CHAR_BIT * sizeof (unsigned int);
       result += CHAR_BIT * sizeof (unsigned int);
     }
+#endif
 }
diff --git a/lib/ffsll.c b/lib/ffsll.c
index d056d7c26..f0e9425ee 100644
--- a/lib/ffsll.c
+++ b/lib/ffsll.c
@@ -1,3 +1,4 @@
 #define FUNC ffsll
 #define TYPE long long int
+#define GCC_BUILTIN __builtin_ffsll
 #include "ffsl.h"