[Issue 12833] switch statement does not work properly when -inline used

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=12833

--- Comment #1 from Kenji Hara <k.hara.pg at gmail.com> ---
This is dmd backend isuse rather than -inline switch.

The test function is inlined to:

    long x = cast(long)a;

    switch (cast(int)(cast(ushort)(x >> 16 & 65535L)))
    {
        case 1:
        {
            writefln("it works!");
            break;
        }
        default:
        {
        }
    }

And the condition of switch statement is always 0.

Reduced test case (can reproduce the issue without -inline):

extern(C) int printf(const char*, ...);
void main()
{
    int a = 0x1_0000;
//00402016: b800000100              mov eax, 0x10000
//0040201b: 8945ec                  mov [ebp-0x14], eax

    long x = cast(long)a;
//0040201e: 89c2                    mov edx, eax
//00402020: c1fa1f                  sar edx, 0x1f
//00402023: 8945f4                  mov [ebp-0xc], eax
//00402026: 8955f8                  mov [ebp-0x8], edx

    int num = cast(int)(cast(ushort)(x >> 16 & 65535L));    // problem!
//00402029: 0facd010                shrd eax, edx, 0x10
//0040202d: c1fa10                  sar edx, 0x10
//00402030: 25ffff0000              and eax, 0xffff
//00402035: 31d2                    xor edx, edx        // <--
//00402037: 8955fc                  mov [ebp-0x4], edx  // <--

    if (num == 1)
//0040203a: 83fa01                  cmp edx, 0x1
//0040203d: 7510                    jnz 0x40204f  D main test.d:15
    {
        printf("it works!\x0a");
    }
    else
        assert(0);  // line 15
}

--