https://issues.dlang.org/show_bug.cgi?id=11418
Issue 11418 depends on issue 10985, which changed state.

Issue 10985 Summary: Compiler doesn't attempt to inline non-templated functions from libraries (even having the full source)
https://issues.dlang.org/show_bug.cgi?id=10985

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

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https://issues.dlang.org/show_bug.cgi?id=11418

Dennis <dkorpel@live.nl> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |dkorpel@live.nl
         Resolution|---                         |FIXED

--- Comment #1 from Dennis <dkorpel@live.nl> ---
Issue 10985 is now fixed, so testing with:

-O -inline
```
import core.bitop: bt;

int foo(ulong* p, ulong bitnum)
{
    return bt(p, bitnum);
}
```

ASM:
```
int onlineapp.foo(ulong*, ulong):
        push    RBP
        mov     RBP,RSP
        mov     RCX,RDI
        shr     RCX,6
        mov     EDX,EDI
        and     EDX,03Fh
        bt      [RCX*8][RSI],EDX
        setb    AL
        and     EAX,1
        pop     RBP
        ret
        add     [RAX],AL
```

The function is inlined and a bt instruction is generated, so it looks like this issue is fixed as well.

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