RE: enabling float128 support in clang?
- Reply: Brooks Davis : "Re: enabling float128 support in clang?"
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Date: Mon, 03 Oct 2022 20:36:55 UTC
Brooks Davis <brooks_at_freebsd.org> wrote on Date: Mon, 03 Oct 2022 18:43:10 UTC : > TL;DR: Is there a reason not to enable float128 support in clang for > x86? > > Due to a build breakage with the flang runtime, I recently noticed that > unlike most other OSes we don't support float128 in clang. It's enable > in modern GCC and other OSes have it enable in clang: > - Hakiu 2018: https://reviews.llvm.org/D54901 > - Solaris 2018: https://reviews.llvm.org/D41240 > - WASM 2019: https://reviews.llvm.org/D57154 > - Dragonfly 2021: https://reviews.llvm.org/D111760 > - OpenBSD (history hard to find...) > > Is there a known reason not to enable this? > > Patch to enable below (I'm a bit skeptical of the __FLOAT128__ part as > GCC doesn't define it...) > > -- Brooks > > diff --git a/clang/lib/Basic/Targets/OSTargets.h b/clang/lib/Basic/Targets/OSTargets.h > index c75f7d9fbafe..ea95f40e81a0 100644 > --- a/clang/lib/Basic/Targets/OSTargets.h > +++ b/clang/lib/Basic/Targets/OSTargets.h > @@ -232,6 +232,9 @@ protected: > // setting this to 1 is conforming even if all the basic source > // character literals have the same encoding as char and wchar_t. > Builder.defineMacro("__STDC_MB_MIGHT_NEQ_WC__", "1"); > + > + if (this->HasFloat128) > + Builder.defineMacro("__FLOAT128__"); > } > > public: > @@ -241,6 +244,7 @@ public: > default: > case llvm::Triple::x86: > case llvm::Triple::x86_64: > + this->HasFloat128 = true; > this->MCountName = ".mcount"; > break; > case llvm::Triple::mips: > > See: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=238129 for some past exchanges on this. From comment #3: QUOTE of Dimitry Andric: As mentioned on the mailing list, it is not a matter of just "enabling" float128. Somebody has to step up and write a BSD licensed quadmath.h, to start with. END QUOTE === Mark Millard marklmi at yahoo.com