qiucf added inline comments.
================
Comment at: clang/lib/Parse/ParseExprCXX.cpp:2245
+ case tok::kw___ibm128:
+ DS.SetTypeSpecType(DeclSpec::TST_ibm128, Loc, PrevSpec, DiagID, Policy);
+ break;
----------------
hubert.reinterpretcast wrote:
> qiucf wrote:
> > hubert.reinterpretcast wrote:
> > > Not sure what the best method is to implement this, but `long double` and
> > > `__ibm128` are the same type for GCC when `-mabi=ibmlongdouble` is in
> > > effect.
> > Seems clang is also different from GCC under `-mabi=ieeelongdouble`? I saw
> > `__float128` and `long double` are the same for GCC but not for clang.
> Have you checked whether the new libstdc++ for which this support is being
> added needs the GCC behaviour to work properly?
>
> The GCC behaviour allows the following to be compiled without introducing
> novel overload resolution tiebreakers:
> ```
> void f(__float128);
> void f(__ibm128);
> void f(int);
>
> long double ld;
>
> int main() { f(ld); }
> ```
As I saw both GCC and clang have error for ambiguous `operator<<` for:
```
std::cout << "long double:\n";
std::cout << std::numeric_limits<long double>::max() << std::endl;
std::cout << std::numeric_limits<long double>::min() << std::endl;
std::cout << "__float128:\n";
std::cout << std::numeric_limits<__float128>::max() << std::endl;
std::cout << std::numeric_limits<__float128>::min() << std::endl;
std::cout << "__ibm128:\n";
std::cout << std::numeric_limits<__ibm128>::max() << std::endl;
std::cout << std::numeric_limits<__ibm128>::min() << std::endl;
```
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D93377/new/
https://reviews.llvm.org/D93377
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