http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55899
Bug #: 55899
Summary: GCC should provide built-ins in <stdint.h> data types
flavor/version/variation
Classification: Unclassified
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: other
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: y...@droneaud.fr
Built-in functions such as
__builtin_clz(unsigned int x)
__builtin_ctz(unsigned int x)
__builtin_ffs(unsigned int x)
etc.
are lacking variant based on C99 <stdint.h> data type.
Currently there's
__builtin_clzl(unsigned long x)
__builtin_clzll(unsigned long long x)
I'd like to have:
__builtin_clz32(uint32_t x)
__builtin_clz64(uint64_t x)
This would help to hard code the number of bits when using such construct to
know the number of bit needed to hold a value:
(8 * sizeof(unsigned int)) - __builtin_clz(value)
when value is of type uint32_t:
32 - __builtin_clz32(value)
Note: there's already __builtin_bswap32(int32_t x) and
__builtin_bswap64(int64_t x)
