On Tue, 15 Aug 2023, chenxiaolong wrote:
> In the implementation process, the "q" suffix function is
> Re-register and associate the "__float128" type with the
> "long double" type so that the compiler can handle the
> corresponding function correctly. The functions implemented
> include __builtin_{huge_valq infq, fabsq, copysignq, nanq,nansq}.
> On the LoongArch architecture, __builtin_{fabsq,copysignq} can
> be implemented with the instruction "bstrins.d", so that its
> optimization effect reaches the optimal value.
Why? If long double has binary128 format, you shouldn't need any of these
functions at all; if it doesn't, just the C23 _Float128 type name and f128
constant suffix, and associated built-in functions defined in
builtins.def, should suffice (and since we now have _FloatN support for
C++, C++ no longer provides a reason for adding __float128 either).
__float128 is a legacy type name and feature and shouldn't be needed on
any new architectures, which can just use the standard type name from the
start.
--
Joseph S. Myers
jos...@codesourcery.com
