@@ -42,7 +42,8 @@
__BEGIN_DECLS
/* Use __pacify_uint16 (N) instead of (uint16_t) (N) when the cast is helpful
- only to pacify older GCC (e.g., GCC 10 -Wconversion) or non-GCC. */
+ only to pacify older GCC (e.g., GCC 10 -Wconversion) or non-GCC (e.g
+ clang -Wimplicit-int-conversion). */
#if __GNUC_PREREQ (11, 0)
# define __pacify_uint8(n) (n)
# define __pacify_uint16(n) (n)
@@ -170,8 +171,8 @@ extern unsigned int stdc_trailing_zeros_ull (unsigned long long int __x)
#define stdc_trailing_zeros(x) \
(sizeof (x) == 8 ? stdc_trailing_zeros_ull (x) \
: sizeof (x) == 4 ? stdc_trailing_zeros_ui (x) \
- : sizeof (x) == 2 ? stdc_trailing_zeros_us (x) \
- : stdc_trailing_zeros_uc (x))
+ : sizeof (x) == 2 ? stdc_trailing_zeros_us (__pacify_uint16 (x)) \
+ : stdc_trailing_zeros_uc (__pacify_uint8 (x)))
#if __GNUC_PREREQ (3, 4) || __glibc_has_builtin (__builtin_ctzll)
static __always_inline unsigned int
@@ -274,8 +275,8 @@ extern unsigned int stdc_first_leading_zero_ull (unsigned long long int __x)
#define stdc_first_leading_zero(x) \
(sizeof (x) == 8 ? stdc_first_leading_zero_ull (x) \
: sizeof (x) == 4 ? stdc_first_leading_zero_ui (x) \
- : sizeof (x) == 2 ? stdc_first_leading_zero_us (x) \
- : stdc_first_leading_zero_uc (x))
+ : sizeof (x) == 2 ? stdc_first_leading_zero_us (__pacify_uint16 (x)) \
+ : stdc_first_leading_zero_uc (__pacify_uint8 (x)))
#if __GNUC_PREREQ (3, 4) || __glibc_has_builtin (__builtin_clzll)
static __always_inline unsigned int
@@ -328,8 +329,8 @@ extern unsigned int stdc_first_leading_one_ull (unsigned long long int __x)
#define stdc_first_leading_one(x) \
(sizeof (x) == 8 ? stdc_first_leading_one_ull (x) \
: sizeof (x) == 4 ? stdc_first_leading_one_ui (x) \
- : sizeof (x) == 2 ? stdc_first_leading_one_us (x) \
- : stdc_first_leading_one_uc (x))
+ : sizeof (x) == 2 ? stdc_first_leading_one_us (__pacify_uint16 (x)) \
+ : stdc_first_leading_one_uc (__pacify_uint8 (x)))
#if __GNUC_PREREQ (3, 4) || __glibc_has_builtin (__builtin_clzll)
static __always_inline unsigned int
@@ -382,8 +383,8 @@ extern unsigned int stdc_first_trailing_zero_ull (unsigned long long int __x)
#define stdc_first_trailing_zero(x) \
(sizeof (x) == 8 ? stdc_first_trailing_zero_ull (x) \
: sizeof (x) == 4 ? stdc_first_trailing_zero_ui (x) \
- : sizeof (x) == 2 ? stdc_first_trailing_zero_us (x) \
- : stdc_first_trailing_zero_uc (x))
+ : sizeof (x) == 2 ? stdc_first_trailing_zero_us (__pacify_uint16 (x)) \
+ : stdc_first_trailing_zero_uc (__pacify_uint8 (x)))
#if __GNUC_PREREQ (3, 4) || __glibc_has_builtin (__builtin_ctzll)
static __always_inline unsigned int
@@ -436,8 +437,8 @@ extern unsigned int stdc_first_trailing_one_ull (unsigned long long int __x)
#define stdc_first_trailing_one(x) \
(sizeof (x) == 8 ? stdc_first_trailing_one_ull (x) \
: sizeof (x) == 4 ? stdc_first_trailing_one_ui (x) \
- : sizeof (x) == 2 ? stdc_first_trailing_one_us (x) \
- : stdc_first_trailing_one_uc (x))
+ : sizeof (x) == 2 ? stdc_first_trailing_one_us (__pacify_uint16 (x)) \
+ : stdc_first_trailing_one_uc (__pacify_uint8 (x)))
#if __GNUC_PREREQ (3, 4) || __glibc_has_builtin (__builtin_ctzll)
static __always_inline unsigned int
With clang 14 and also with main the tst-stdbit-Wconversion issues the warnings: ../stdlib/stdbit.h:701:40: error: implicit conversion loses integer precision: 'int' to 'uint16_t' (aka 'unsigned short') [-Werror,-Wimplicit-int-conversion] return __x == 0 ? 0 : ((uint16_t) 1) << (__bw16_inline (__x) - 1); ~~~~~~ ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~ ../stdlib/stdbit.h:707:39: error: implicit conversion loses integer precision: 'int' to 'uint8_t' (aka 'unsigned char') [-Werror,-Wimplicit-int-conversion] return __x == 0 ? 0 : ((uint8_t) 1) << (__bw8_inline (__x) - 1); ~~~~~~ ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~ ../stdlib/stdbit.h:751:40: error: implicit conversion loses integer precision: 'int' to 'uint16_t' (aka 'unsigned short') [-Werror,-Wimplicit-int-conversion] return __x <= 1 ? 1 : ((uint16_t) 2) << (__bw16_inline (__x - 1) - 1); ~~~~~~ ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ../stdlib/stdbit.h:757:39: error: implicit conversion loses integer precision: 'int' to 'uint8_t' (aka 'unsigned char') [-Werror,-Wimplicit-int-conversion] return __x <= 1 ? 1 : ((uint8_t) 2) << (__bw8_inline (__x - 1) - 1); ~~~~~~ ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ tst-stdbit-Wconversion.c:45:31: error: implicit conversion loses integer precision: 'unsigned short' to 'uint8_t' (aka 'unsigned char') [-Werror,-Wimplicit-int-conversion] (void) stdc_trailing_zeros (us); ~~~~~~~~~~~~~~~~~~~~~^~~ ../stdlib/stdbit.h:164:30: note: expanded from macro 'stdc_trailing_zeros' : stdc_trailing_zeros_uc (x)) ~~~~~~~~~~~~~~~~~~~~~~~~^~ ../stdlib/stdbit.h:191:52: note: expanded from macro 'stdc_trailing_zeros_uc' # define stdc_trailing_zeros_uc(x) (__ctz8_inline (x)) ~~~~~~~~~~~~~ ^ tst-stdbit-Wconversion.c:46:31: error: implicit conversion loses integer precision: 'unsigned int' to 'uint16_t' (aka 'unsigned short') [-Werror,-Wimplicit-int-conversion] (void) stdc_trailing_zeros (ui); ~~~~~~~~~~~~~~~~~~~~~^~~ ../stdlib/stdbit.h:163:48: note: expanded from macro 'stdc_trailing_zeros' : sizeof (x) == 2 ? stdc_trailing_zeros_us (x) \ ~~~~~~~~~~~~~~~~~~~~~~~~^~ ../stdlib/stdbit.h:192:53: note: expanded from macro 'stdc_trailing_zeros_us' # define stdc_trailing_zeros_us(x) (__ctz16_inline (x)) ~~~~~~~~~~~~~~ ^ tst-stdbit-Wconversion.c:46:31: error: implicit conversion loses integer precision: 'unsigned int' to 'uint8_t' (aka 'unsigned char') [-Werror,-Wimplicit-int-conversion] (void) stdc_trailing_zeros (ui); ~~~~~~~~~~~~~~~~~~~~~^~~ ../stdlib/stdbit.h:164:30: note: expanded from macro 'stdc_trailing_zeros' : stdc_trailing_zeros_uc (x)) ~~~~~~~~~~~~~~~~~~~~~~~~^~ ../stdlib/stdbit.h:191:52: note: expanded from macro 'stdc_trailing_zeros_uc' # define stdc_trailing_zeros_uc(x) (__ctz8_inline (x)) ~~~~~~~~~~~~~ ^ tst-stdbit-Wconversion.c:47:31: error: implicit conversion loses integer precision: 'unsigned long' to 'uint16_t' (aka 'unsigned short') [-Werror,-Wimplicit-int-conversion] (void) stdc_trailing_zeros (ul); ~~~~~~~~~~~~~~~~~~~~~^~~ ../stdlib/stdbit.h:163:48: note: expanded from macro 'stdc_trailing_zeros' : sizeof (x) == 2 ? stdc_trailing_zeros_us (x) \ ~~~~~~~~~~~~~~~~~~~~~~~~^~ ../stdlib/stdbit.h:192:53: note: expanded from macro 'stdc_trailing_zeros_us' # define stdc_trailing_zeros_us(x) (__ctz16_inline (x)) ~~~~~~~~~~~~~~ ^ [...] It seems to boiler down to __builtin_clz not having a variant for 8 or 16 bits. Fix it by explicit casting to the expected types. Although not strickly required for older gcc, using the same __pacify macro simpify the required code. Checked on x86_64-linux-gnu and i686-linux-gnu. --- stdlib/stdbit.h | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-)