[PATCH] D134744: [clang][Interp] Implement rem opcode

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added inline comments.


================
Comment at: clang/test/AST/Interp/literals.cpp:161
+                                        // expected-note {{division by zero}}
+
+
----------------
tbaeder wrote:
> aaron.ballman wrote:
> > tbaeder wrote:
> > > aaron.ballman wrote:
> > > > Same question here as with div in regards to testing float behavior. (If you don't intend to support floats yet, make sure the commit message makes that clear.)
> > > Ultimately sure, but as of right now, floats aren't supported at all, so nope.
> > Okay, fine by me.
> > 
> > In terms of the request by @shafik for `INT_MIN % -1`, keep in mind there are arbitrary width integer types like `_BitInt`, so you should add test coverage for code like:
> > ```
> > constexpr _BitInt(7) Val = -64;
> > static_assert(Val % (_BitInt(7)-1, "");
> > ```
> > and similar for division.
> I just checked, `_BitInt` doesn't work at all; it bails out when creating the `Descriptor` for the variable.
> 
> I already added the suggested note for the `INT_MIN` case in this patch, but I wasn't sure how to test is properly. Should I just use a fixed-width integer type and copy its `_MIN` value in the test?
Ah, well that's something we should fix! :-D

> I already added the suggested note for the INT_MIN case in this patch, but I wasn't sure how to test is properly. Should I just use a fixed-width integer type and copy its _MIN value in the test?

You should be able to use:
```
#define INT_MIN (~__INT_MAX__)
```
(and similar for the other MIN macros) which relies on the predefined macro instead of something from a header.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D134744/new/

https://reviews.llvm.org/D134744