diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 07b6a6ca338..f892f00f2b7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2012-08-20  Joseph Myers  <joseph@codesourcery.com>
+
+	* configure.ac (ffs): Check for declaration.
+	* configure, config.in: Regenerate.
+
 2012-08-20  Richard Guenther  <rguenther@suse.de>
 
 	* tree-flow.h (register_new_name_mapping): Remove.
diff --git a/gcc/config.in b/gcc/config.in
index a9417dfd80b..7fe6485c3af 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -621,6 +621,12 @@
 #endif
 
 
+/* Define to 1 if we found a declaration for 'ffs', otherwise define to 0. */
+#ifndef USED_FOR_TARGET
+#undef HAVE_DECL_FFS
+#endif
+
+
 /* Define to 1 if we found a declaration for 'fgetc_unlocked', otherwise
    define to 0. */
 #ifndef USED_FOR_TARGET
diff --git a/gcc/configure b/gcc/configure
index 7f3489d0e8f..47106e4f8e9 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -10288,7 +10288,7 @@ CXXFLAGS="$CXXFLAGS -I${srcdir} -I${srcdir}/../include"
 for ac_func in getenv atol asprintf sbrk abort atof getcwd getwd \
 	strsignal strstr stpcpy strverscmp \
 	errno snprintf vsnprintf vasprintf malloc realloc calloc \
-	free basename getopt clock getpagesize clearerr_unlocked feof_unlocked   ferror_unlocked fflush_unlocked fgetc_unlocked fgets_unlocked   fileno_unlocked fprintf_unlocked fputc_unlocked fputs_unlocked   fread_unlocked fwrite_unlocked getchar_unlocked getc_unlocked   putchar_unlocked putc_unlocked
+	free basename getopt clock getpagesize ffs clearerr_unlocked feof_unlocked   ferror_unlocked fflush_unlocked fgetc_unlocked fgets_unlocked   fileno_unlocked fprintf_unlocked fputc_unlocked fputs_unlocked   fread_unlocked fwrite_unlocked getchar_unlocked getc_unlocked   putchar_unlocked putc_unlocked
 do
   ac_tr_decl=`$as_echo "HAVE_DECL_$ac_func" | $as_tr_cpp`
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $ac_func is declared" >&5
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 6bfbf354d1c..7042c9116ec 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -1075,7 +1075,7 @@ CXXFLAGS="$CXXFLAGS -I${srcdir} -I${srcdir}/../include"
 gcc_AC_CHECK_DECLS(getenv atol asprintf sbrk abort atof getcwd getwd \
 	strsignal strstr stpcpy strverscmp \
 	errno snprintf vsnprintf vasprintf malloc realloc calloc \
-	free basename getopt clock getpagesize gcc_UNLOCKED_FUNCS, , ,[
+	free basename getopt clock getpagesize ffs gcc_UNLOCKED_FUNCS, , ,[
 #include "ansidecl.h"
 #include "system.h"])