Re: enabling float128 support in clang?
- In reply to: Brooks Davis : "Re: enabling float128 support in clang?"
- Go to: [ bottom of page ] [ top of archives ] [ this month ]
Date: Tue, 04 Oct 2022 16:05:21 UTC
On Tue, Oct 04, 2022 at 03:57:39PM +0000, Brooks Davis wrote: > On Tue, Oct 04, 2022 at 04:02:05PM +0100, Alexander Richardson wrote: > > On Mon, 3 Oct 2022 at 19:43, Brooks Davis <email@example.com> wrote: > > > > > > 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: > > > > > > > I think this makes sense and may even motivate me to try and get the > > necessary library calls merged to compiler-rt > > (https://reviews.llvm.org/D98261). > > Sounds good. I'll submit a review. https://reviews.llvm.org/D98261 -- Brooks