arphaman added inline comments.
================
Comment at: lib/Sema/AnalysisBasedWarnings.cpp:530
+ // Don't need to mark Objective-C methods or blocks since the undefined
+ // behaviour optimization isn't used for them.
+}
----------------
mehdi_amini wrote:
> Quuxplusone wrote:
> > This seems like a trap waiting to spring on someone, unless there's a
> > technical reason that methods and blocks cannot possibly use the same
> > optimization paths as regular functions. ("Nobody's gotten around to
> > implementing it yet" is the most obvious nontechnical reason for the
> > current difference.) Either way, I'd expect this patch to include test
> > cases for both methods and blocks, to verify that the behavior you expect
> > is actually the behavior that happens. Basically, it ought to have a
> > regression test targeting the regression that I'm predicting is going to
> > spring on someone as soon as they implement optimizations for methods and
> > blocks.
> >
> > Also, one dumb question: what about C++ lambdas? are they FunctionDecls
> > too? test case?
> > This seems like a trap waiting to spring on someone, unless there's a
> > technical reason that methods and blocks cannot possibly use the same
> > optimization paths as regular functions.
>
> The optimization path in LLVM is the same. I think the difference lies in
> clang IRGen: there is no "unreachable" generated for these so the optimizer
> can't be aggressive. So this patch is not changing anything for Objective-C
> methods and blocks, and I expect that we *already* have a test that covers
> this behavior (if not we should add one).
Mehdi is right, the difference is in IRGen - methods and blocks never get the
trap and unreachable IR return optmisation. I don't think we have a test for
this though, so I added a regression test case that verifies this.
Repository:
rL LLVM
https://reviews.llvm.org/D27163
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
