Hi all,Generally the `__builtin_expect()` functions is used to inform the compiler about whether a branch is likely to be taken. But given this example:
```c++
#ifdef USE_TERNARY
# define EXPECT(...) __builtin_expect((__VA_ARGS__)?1:0,1)
#else
# define EXPECT(...) __builtin_expect(!!(__VA_ARGS__),1)
#endif
struct data
{
char* ptr;
int get_flags_slow() const;
int get_flags() const
{
if(EXPECT(!this->ptr))
return 0;
return this->get_flags_slow();
}
int use() const;
};
int gdata(const data* p)
{
int flags = p->get_flags();
return flags & p->use();
}
```
when `USE_TERNARY` is defined, the ternary operator is used to contextually convert the condition
expression to type `bool`, which seems to invalidate the hint for GCC (not for clang), as shown in
<https://gcc.godbolt.org/z/fvqYbh>. The traditional way of forcing such conversion (when
`USE_TERNARY` is not defined) does not suffer from this issue. What could be the potential cause of
this differentiation? Thanks in advance.
-- Best regards, Liu Hao
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