erichkeane added inline comments.
================
Comment at: clang/lib/AST/ExprConstant.cpp:13540
ED->getValueRange(Max, Min);
+ --Max;
----------------
shafik wrote:
> erichkeane wrote:
> > I don't think this is the correct answer. Even though the other use of
> > this seems to 'work', `getValueRange` is still returning wrapped values
> > here. The fix is to figure out how to fix the math in getValueRange, and
> > change the sanitizer's IR generation if necessary.
> So the other user of these values is `getRangeForLoadFromType(...)` through
> `getRangeForType(...)` which is used to generate the [range
> metadata](https://llvm.org/docs/LangRef.html#range-metadata) and in this case
> the range is exclusive on the right side:
>
> > The pair a,b represents the range [a,b).
>
> and it is allowed to wrap:
>
> > The range is allowed to wrap.
>
> So I believe the behavior will be correct.
>
> Even though the range looks off in this example:
> https://godbolt.org/z/z7d9PKoMn
>
> ```
> !{i32 0, i32 -2147483648}
> ```
>
> I think it does the right thing.
>
> Note the language ref also says:
>
> > The type must match the type loaded by the instruction.
>
> and a quick experiment to use `i33` confirms this breaks.
Hmm... ok. Well, its quite unfortunate that 2 of our 3 uses of this are having
to hack around this behavior a bit, but I guess this will have to be acceptable
short-term then.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D130811/new/
https://reviews.llvm.org/D130811
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
