Segfault: bitfields in inline assembly

[ibuclaw]

Runnable example.

struct S { int x : 8; }

void f(ref S s, int y)
{
    asm { "mov %1, %0" : "=r" (s.x) : "r" (y); }
}

void main()
{
    S s;
    f(s, 15);
    assert(s.x == 15);
}

0  ldc2      0x0000621ef8d4a0e7 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 39
1  ldc2      0x0000621ef8d47eec llvm::sys::RunSignalHandlers() + 188
2  ldc2      0x0000621ef8d4a78f
3  libc.so.6 0x0000735c9061f330
4  ldc2      0x0000621ef9055767 GccAsmStatement_toIR(GccAsmStatement*, IRState*) + 1895
5  ldc2      0x0000621ef8fd5398 CompoundAsmStatement_toIR(CompoundAsmStatement*, IRState*) + 4696
6  ldc2      0x0000621ef9053a7b
7  ldc2      0x0000621ef8fe5f04 DtoDefineFunction(FuncDeclaration*, bool) + 7076
8  ldc2      0x0000621ef9013352 codegenModule(IRState*, Module*) + 4274
9  ldc2      0x0000621ef90b9445 ldc::CodeGenerator::emit(Module*) + 213
10 ldc2      0x0000621ef5880f5a codegenModules(Array<Module*>&) + 938
11 ldc2      0x0000621ef5884865 mars_tryMain(Param&, Array<char const*>&) + 2069
12 ldc2      0x0000621ef58d1bc0 cppmain() + 9376
13 ldc2      0x0000621ef9275aed _D2rt6dmain212_d_run_main2UAAamPUQgZiZ6runAllMFZv + 77
14 ldc2      0x0000621ef92758c4 _d_run_main2 + 468
15 ldc2      0x0000621ef92756dd _d_run_main + 141
16 ldc2      0x0000621ef90b5fc8 main + 680
17 libc.so.6 0x0000735c906041ca
18 libc.so.6 0x0000735c9060428b __libc_start_main + 139
19 ldc2      0x0000621ef58d678e _start + 46
Segmentation fault (core dumped)

---

Other examples that should fail

struct T { int m : 32; }
void mwrite(T t) { asm { "" : "=m" (t.m); } // taking address of bitfield
void mread(T t) { asm { "" :: "m" (t.m); } // taking address of bitfield

The C equivalent to all of the above (importC) should succeed or fail in the same way as well.