https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97503
LIU Hao <lh_mouse at 126 dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |lh_mouse at 126 dot com
--- Comment #4 from LIU Hao <lh_mouse at 126 dot com> ---
Are there any reasons why this was not done for 64?
(https://gcc.godbolt.org/z/7vddPdxaP)
```
using int32_t = int;
using int64_t = long long;
using uint32_t = unsigned int;
using uint64_t = unsigned long long;
void
xlzcnt32(int32_t& val)
{
val = val ? (__builtin_clz(val) & 31) : 32;
}
void
xlzcnt64(int64_t& val)
{
val = val ? (__builtin_clzll(val) & 63) : 64;
}
```
results in
```
xlzcnt32(int&):
xor eax, eax
lzcnt eax, DWORD PTR [rdi]
mov DWORD PTR [rdi], eax
ret
xlzcnt64(long long&):
mov rdx, QWORD PTR [rdi]
xor eax, eax
lzcnt rax, rdx
test rdx, rdx
mov edx, 64
cmove rax, rdx
mov QWORD PTR [rdi], rax
ret
```
