[Bug target/122018] x86 doesn't use BTS bitmanip instruction to both set and test bit

[uis9936 at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122018

--- Comment #5 from uis <uis9936 at gmail dot com> ---
I posted code that probably would be easier for optimizer, more common pattern
I think would be

#include <stdbool.h>
void g();
void h();
int f(int a, int b) {
    if(a & (1 << b)) {
        g();
        a = a | (1 << b);
    } else
        h();
    return a;
}