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authorXi Ruoyao <xry111@xry111.site>2024-02-04 08:27:50 +0800
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2024-02-05 15:19:41 -0300
commit2e80f139376450acdb7d879d799439578a41810e (patch)
tree9888c8627c488da707f338232ab4c480c618eba9 /sysdeps
parent814ed22eab4f3f43bb02229edab5d50004310258 (diff)
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LoongArch: Use builtins for ffs and ffsll
On LoongArch GCC compiles __builtin_ffs{,ll} to basically
`(x ? __builtin_ctz (x) : -1) + 1`.  Since a hardware ctz instruction is
available, this is much better than the table-driven generic
implementation.

Tested on loongarch64.

Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/loongarch/math-use-builtins-ffs.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/sysdeps/loongarch/math-use-builtins-ffs.h b/sysdeps/loongarch/math-use-builtins-ffs.h
new file mode 100644
index 0000000000..a83bb15414
--- /dev/null
+++ b/sysdeps/loongarch/math-use-builtins-ffs.h
@@ -0,0 +1,2 @@
+#define USE_FFS_BUILTIN   1
+#define USE_FFSLL_BUILTIN 1