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From: Xi Ruoyao <xry111@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc r13-3269] LoongArch: implement count_{leading,trailing}_zeros Date: Thu, 13 Oct 2022 10:05:43 +0000 (GMT) [thread overview] Message-ID: <20221013100543.C1C423850208@sourceware.org> (raw) 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. */ \
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