erichkeane added inline comments.
================
Comment at: clang/lib/AST/Interp/ByteCodeExprGen.cpp:620
+ case UO_Deref: // *x
+ case UO_Not: // ~x
+ case UO_Real: // __real x
----------------
tbaeder wrote:
> aaron.ballman wrote:
> > tbaeder wrote:
> > > aaron.ballman wrote:
> > > > This is reachable and will always return true thanks to the magic of
> > > > integer promotions:
> > > > ```
> > > > void func() {
> > > > bool b = true;
> > > > b = ~b;
> > > > }
> > > > ```
> > > This code path is not just for boolean values though.
> > All the more reason to be worried about `~` being marked as unreachable (I
> > mostly worry because people often try to make bit fiddling operations
> > constant expressions when possible, so this seems pretty likely to be hit).
> > Perhaps make it into an `assert(false && "operation not supported yet");`
> > or something more loud?
> How is that different? It's just a marker for me so I know later in
> development that this is not implemented yet. And now that I'm writing this,
> I guess I see what you mean. Yes, it's not unreachable, but it shouldn't be
> reached when testing what is currently implemented.
Aaron: we tend to NEVER use 'assert(false...' and instead use llvm_unreachable
for 'not implemented yet' quite often in clang. I don't see the semantic
difference here?
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D132098/new/
https://reviews.llvm.org/D132098
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