[PATCH] D50979: Eliminate instances of `EmitScalarExpr(E->getArg(n))` in EmitX86BuiltinExpr().

[Nico Weber via Phabricator via cfe-commits]

thakis added a comment.

In https://reviews.llvm.org/D50979#1206282, @thakis wrote:

> In https://reviews.llvm.org/D50979#1206211, @rsmith wrote:
>
> > I don't think this is NFC. Testcase:
> >
> >   long long int a, b, c, d;
> >   unsigned char f() { return _InterlockedCompareExchange128(&(++a), ++b, ++c, &(++d)); }
> >
> >
> > Today, Clang increments `a`, `b`, `c`, and `d` twice each in `f()`.
>
>
> Thanks for pointing this out, good to hear that this even happens to find a bug :-) I'll add some tests to document the progression.


*happens to _fix_ a bug


https://reviews.llvm.org/D50979