[gcc r13-3269] LoongArch: implement count_{leading,trailing}_zeros

[gcc r13-3269] LoongArch: implement count_{leading,trailing}_zeros

[Xi Ruoyao]

https://gcc.gnu.org/g:6f653a2c85a450714bac905ea4f153234bc6cd5f

commit r13-3269-g6f653a2c85a450714bac905ea4f153234bc6cd5f
Author: Xi Ruoyao <xry111@xry111.site>
Date:   Wed Oct 12 22:06:07 2022 +0800

    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.

Diff:
---
 include/longlong.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/longlong.h b/include/longlong.h
index 64a7b10f9b2..c3a6f1e7eaa 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.  */ \