On Mon, Oct 30, 2017 at 04:16:42PM +0000, Joseph Myers wrote: > This has broken building the mainline glibc testsuite with GCC mainline > for platforms where long double has binary128 format. > > Recall that _FloatN type names are not supported for C++, because of the > expectation that any C++ bindings for such types would be class-based like > the TR 24733 DFP support rather than using built-in types such as > _Float128. Thus glibc uses __float128 to define _Float128 internally for > C++ where __float128 is available, but where it is not available but long > double has that format, the headers use long double to implement > _Float128. Thus you get conflicting declarations, headers declaring > sqrtf128 to use a typedef for long double but the built-in functions using > the internal _Float128 type that has no built-in name referring directly > to it for C++. > > One obvious possible fix would be for the builtins.def macros never to > define public names such as sqrtf128 for C++, only ever for C. That would > be on the basis that C++ code is expected to be using a sqrt overload > anyway - so making the built-in function available under a public name, in > the case where __float128 exists for C++, is a matter for libstdc++ > headers.
Arghh, yes, I can restrict it to just the C language. Would you prefer just that? Do we want a target hook to be able to over-ride this on a platform basis (with the default behavior only enabling it for C)? -- Michael Meissner, IBM IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA email: meiss...@linux.vnet.ibm.com, phone: +1 (978) 899-4797
