[glibc] mips: Use builtins for ffs and ffsll

[glibc] mips: Use builtins for ffs and ffsll

[Adhemerval Zanella]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=545480506fc6576ea37a14e56c654935c691709d

commit 545480506fc6576ea37a14e56c654935c691709d
Author: Junxian Zhu <zhujunxian@oss.cipunited.com>
Date:   Tue Feb 6 16:34:56 2024 +0800

    mips: Use builtins for ffs and ffsll
    
    __builtin_ffs{,ll} basically on __builtin_ctz{,ll} in MIPS GCC compiler.
    The hardware ctz instructions were available after MIPS{32,64} Release1. By using builtin ctz. It can also reduce code size of ffs/ffsll.
    
    Checked on mips o32. mips64.
    
    Signed-off-by: Junxian Zhu <zhujunxian@oss.cipunited.com>
    Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
    Reviewed-by: Maxim Kuvyrkov <maxim.kuvyrkov@linaro.org>

Diff:
---
 sysdeps/mips/math-use-builtins-ffs.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sysdeps/mips/math-use-builtins-ffs.h b/sysdeps/mips/math-use-builtins-ffs.h
new file mode 100644
index 0000000000..2ab6a03a16
--- /dev/null
+++ b/sysdeps/mips/math-use-builtins-ffs.h
@@ -0,0 +1,3 @@
+#include <sysdep.h>
+#define USE_FFS_BUILTIN (__mips_isa_rev >= 1)
+#define USE_FFSLL_BUILTIN (__mips_isa_rev >= 1)