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authorTavian Barnes <tavianator@tavianator.com>2023-11-10 12:28:00 -0500
committerTavian Barnes <tavianator@tavianator.com>2023-11-10 21:13:36 -0500
commit208376ef99da243545efcd6fb02d3469b4c068ed (patch)
treeb7155aa6823ad9488fa23402e689cf131878ef9d /src
parent4efbe8eca395c90fc0053c7ba1038ccb7bf69e61 (diff)
downloadbfs-208376ef99da243545efcd6fb02d3469b4c068ed.tar.xz
bit: Implement a branchless has_single_bit()
Diffstat (limited to 'src')
-rw-r--r--src/bit.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/src/bit.h b/src/bit.h
index 21a8076..e680fed 100644
--- a/src/bit.h
+++ b/src/bit.h
@@ -350,7 +350,8 @@ UINT_OVERLOADS(FIRST_TRAILING_ONE)
#define HAS_SINGLE_BIT(type, suffix, width) \
static inline bool has_single_bit##suffix(type n) { \
- return n && !(n & (n - 1)); \
+ /** Branchless n && !(n & (n - 1)) */ \
+ return n < (n ^ (n - 1)) + 1; \
}
UINT_OVERLOADS(ROTATE_LEFT)