Fix a latent bug in the asm code. I think that technically, using "*m0" instead of "*0" allows LLVM to pick between using the same memory as output 0 and using a new memory location. (So far I haven't been able to construct a testcase that actually breaks because of this, though)

module bug1;
struct Foo { Foo opSub(ref Foo b) { return Foo(); } }
struct Bar { Foo whee; }
void test(ref Bar moo) { Foo nngh; auto plonk = nngh - moo.whee; }
void main() { Bar bar; test(bar); }