From ad6541a22dd909a04d745b42c8da5e04733efec4 Mon Sep 17 00:00:00 2001
From: Xi Ruoyao <xry111@xry111.site>
Date: Wed, 12 Oct 2022 22:06:07 +0800
Subject: [PATCH 023/124] LoongArch: implement count_{leading,trailing}_zeros
LoongArch always support clz and ctz instructions, so we can always use
__builtin_{clz,ctz} for count_{leading,trailing}_zeros. This improves
the code of libgcc, and also benefits Glibc once we merge longlong.h
there.
Bootstrapped and regtested on loongarch64-linux-gnu.
include/ChangeLog:
* longlong.h [__loongarch__] (count_leading_zeros): Define.
[__loongarch__] (count_trailing_zeros): Likewise.
[__loongarch__] (COUNT_LEADING_ZEROS_0): Likewise.
Signed-off-by: Peng Fan <fanpeng@loongson.cn>
Signed-off-by: ticat_fp <fanpeng@loongson.cn>
---
include/longlong.h | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/include/longlong.h b/include/longlong.h
index 64a7b10f9..c3a6f1e7e 100644
--- a/include/longlong.h
+++ b/include/longlong.h
@@ -593,6 +593,18 @@ extern UDItype __umulsidi3 (USItype, USItype);
#define UMUL_TIME 14
#endif
+#ifdef __loongarch__
+# if W_TYPE_SIZE == 32
+# define count_leading_zeros(count, x) ((count) = __builtin_clz (x))
+# define count_trailing_zeros(count, x) ((count) = __builtin_ctz (x))
+# define COUNT_LEADING_ZEROS_0 32
+# elif W_TYPE_SIZE == 64
+# define count_leading_zeros(count, x) ((count) = __builtin_clzll (x))
+# define count_trailing_zeros(count, x) ((count) = __builtin_ctzll (x))
+# define COUNT_LEADING_ZEROS_0 64
+# endif
+#endif
+
#if defined (__M32R__) && W_TYPE_SIZE == 32
#define add_ssaaaa(sh, sl, ah, al, bh, bl) \
/* The cmp clears the condition bit. */ \
--
2.33.0